Supramolecular hydrogels for wound repair and hemostasis

Shaowen Zhuo ^a, Yongping Liang ^a, Zhengying Wu ^a, Xin Zhao *^a, Yong Han *^ab and Baolin Guo *^abc
aState Key Laboratory for Mechanical Behavior of Materials, and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an, 710049, China. E-mail: zhaoxinbio@mail.xjtu.edu.cn; yonghan@mail.xjtu.edu.cn; baoling@mail.xjtu.edu.cn
^bDepartment of Orthopaedics, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, 710061, China
^cKey Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, 710049, China

First published on 27th October 2023

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Shaowen Zhuo

Shaowen Zhuo received his bachelor's degree from Xi’an University of Science and Technology in 2022. He is now a master's student at Xi’an Jiaotong University under the supervision of Assoc. Prof. Xin Zhao. His research interests include biomedical polymer and hydrogel wound dressing. He is currently working on supramolecular hydrogel dressings.

Xin Zhao

Xin Zhao received his PhD degree in materials science and engineering from Xi’an Jiaotong University in 2018 under the supervision of Prof. Peter X. Ma and Prof. Baolin Guo. He is currently working as an associate professor in the School of Materials Science and Engineering at Xi’an Jiaotong University. His research focuses on biomedical polymers including biomedical polymer synthesis and modification, design and development of biodegradable electroactive polymers, multifunctional biomedical hydrogels, cryogels and elastomers, and their applications for hemostasis, skin wound healing, and skeletal muscle tissue engineering.

Yong Han

Yong Han is a full professor at Xi’an Jiaotong University. He received his PhD degree in materials science and engineering from Northwestern Polytechnical University in 1995. His research interest is focused on biological functional modification of biometals, and biomedical and biomimetic materials. He was awarded the first prize of Shaanxi Provincial Science and Technology in 2006 and the second prize of Shaanxi Provincial Science and Technology in 2010. He was also honored with “Cross-Century Excellent Talents” by the Ministry of Education of China in 2001 and was recognized as the Special Allowance Expert of State Council of China in 2005.

Baolin Guo

Baolin Guo received his PhD degree from the Department of Fiber and Polymer Technology in 2011 at the Royal Institute of Technology (KTH) under the supervision of Professor Ann-Christine Albertsson. He is a professor at the Frontier Institute of Science and Technology (FIST), Xi’an Jiaotong University. His research focuses on biomedical polymers including degradable conductive polymers for tissue engineering application, multifunctional hydrogels for wound healing, rapid hemostasis materials, tissue regeneration, adhesives, human motion sensing devices and controlled drug delivery systems.

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Wider impact Over the past few years, supramolecular hydrogels have gained increasing attention in the field of hemostasis and wound repair due to their unique cross-linking and high designability, making them significantly different from traditional chemical hydrogels. However, the relationship between the network design of supramolecular hydrogel dressings and their unique biomedical functions, as well as the status and future trends of supramolecular hydrogel dressings, has not been systematically summarized. In this review, we provide a comprehensive summary of the main cross-linking methods and their cross-linking principles, and elaborate the relationship between various network structures and the properties of supramolecular hydrogels. Additionally, we summarize the functions of supramolecular hydrogels in promoting hemostasis and wound repair, and discuss the methods for realizing each specific function. At the end of the paper, we put forward the current challenges and feasible countermeasures related to supramolecular hydrogels, and forecast the future development trends of supramolecular hydrogels, encompassing network design, wound healing and hemostatic applications. We hope that this review will help researchers to gain a deeper understanding of supramolecular hydrogels and their applications in hemostasis and wound repair, paving the way for the emergence of better supramolecular hydrogel dressings in the future.

1 Introduction

The skin is one of the most vital organs of the human body, which can make direct contact with the external environment, detect external stimuli, regulate body temperature, and protect the body from external damages. As a result, skin is one of the most vulnerable tissues. Hemostasis, inflammation, proliferation, and remodeling are the four stages of skin wound healing.¹ Excessive bleeding can lead to symptoms of anemia and insufficient blood volume in patients, or hemorrhagic shock and even death in severe cases such as car accidents, on the battlefield, operation or in patients with blood clotting disorders. Timely hemostasis is necessary, as it can prevent the occurrence of shock and enable the progression to the next stage of wound healing.^2,3 The inflammation, proliferation, and remodeling are also important parts of the wound healing process. Although most common skin injuries can heal, various factors may cause a wide range of wound healing problems (including producing scar tissue and hindering the regeneration of appendages),^4–7 such as excessive inflammation, burns, full-thickness skin defects, infection and diabetic wounds, which lead to difficulties in wound repair. Therefore, it is necessary to develop wound dressings to facilitate the wound healing process including hemostasis and subsequent high quality wound repair.

Ideal wound dressings should satisfy the following requirements to accelerate wound healing: good biocompatibility and moisture retention, adequate mechanical strength, and suitable biochemical properties.^8,9 Hydrogels are widely used as soft materials that can absorb large amounts of water while maintaining their integrity. Hydrogels have high water content and good flexibility and possess a number of properties similar to those of soft tissues in the human body. Hydrogels are often biocompatible and can be designed to show a good anti-adhesion effect against proteins in body fluids. In addition, hydrogels can be easily designed to show responsiveness to various stimuli. These properties enable hydrogels to be used in critical biomedical applications such as use as adhesives, dressings, drug/cell delivery systems, and scaffolds.^10,11 Thus, hydrogels are the most competitive dressing materials and there has been an increasing use of hydrogels as wound dressings in recent years.^12–15

Chemically cross-linked hydrogels with permanent covalent bonds are relatively stable, possessing high stiffness and resistance to rapid degradation. However, when the hydrogel networks are broken, their 3D structures are irreversibly broken.^16–18 In contrast, supramolecular hydrogels are formed through reversible non-covalent interactions (hydrogen bonds, electrostatic interactions, hydrophobic interactions, host–guest interactions, metal ligand coordination or other interactions) between macromolecules and/or small molecules. These non-covalent interactions are usually reversible and can respond to external stimuli. When the external environment changes or artificial stimuli occur, the non-covalent bonds will respond by breaking or recombining, showing the properties of reversible expansion, gel–sol transformation, injectable capacity under environmental stimulation, self-healing, shape memory or other properties.¹⁹ Moreover, they are biocompatible and easily degradable. More importantly, these reversible properties provide the foundation for the application of supramolecular hydrogels as delivery systems and tissue engineering scaffolds.^20–22 Therefore, supramolecular hydrogels have gained popularity in the field of wound dressings, and nowadays a variety of functions (antibacterial properties, tissue adhesion, anti-inflammatory function, antioxidation, and functions of cell control) are introduced in supramolecular hydrogels, leading to the development of more multi-functional supramolecular hydrogel dressings.

Recently, research on supramolecular hydrogels has gained significant momentum, and the number of reviews on supramolecular hydrogels and related fields has also been increasing year by year. These reviews mostly focus on the introduction of different kinds of supramolecular interactions,²³ comparisons between supramolecular hydrogels and covalent macromolecular hydrogels,²⁴ recent technologies of various characterization methods²⁵ and so on. However, there has never been a thorough analysis of supramolecular hydrogels for hemostasis and wound repair. In this review, we discuss the cross-linking interactions and network structures of supramolecular hydrogels in detail, and focus on their applications in wound repair and hemostasis. We have outlined the specific functions of supramolecular hydrogels that have emerged over the last decade in wound repair and hemostasis, and highlighted their structural features, and the underlying mechanisms that enable hydrogels to achieve these functions. Specifically, the functions related to promoting wound repair are divided into antibacterial activity, tissue adhesion, substance delivery, anti-inflammatory and antioxidant functions, control of cell behaviors, pro-angiogenesis function and other functions. We subsequently classified the functions of hemostasis into physical hemostasis and coagulation promotion. In addition, the design of supramolecular hydrogel dressings and the challenges they face in wound repair and hemostasis are discussed, and more detailed prospects are presented to stimulate further research in this field.

2 Cross-linking and characteristics of supramolecular hydrogels

The 3D structure of hydrogel is formed by cross-linking the polymer chains (one or more). The effect of one or more non-covalent cross-linking interactions on the properties and even the functions of supramolecular hydrogels cannot be ignored. In this section, the cross-linking methods and properties of supramolecular hydrogels will be described in six parts (hydrogen bonds, electrostatic interactions, hydrophobic interactions, host–guest interactions, metal ligand coordination and other interactions). Table 1 summarizes supramolecular hydrogels with different cross-linking interactions and their characteristics.

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2.1 Hydrogen bonds

Hydrogen bonding is a widely studied supramolecular interaction with reversibility, directionality and sensitivity.⁸⁷ It widely exists between hydrogen atoms of different groups, such as hydroxyl, amino, amide, and strong electronegative atoms with lone pair electrons (such as O, N, and F).^23,87 The hydrogen atom will acquire a positive charge when bonding with the extremely electronegative atoms mentioned above, while the electronegative atom will have a negative charge.^23,88 Hydrogen bonding is crucial to many chemical systems and biological processes in nature, and it is also an important driving force for the construction of hydrogels.⁸⁷ Although a single hydrogen bond is weaker than a single covalent or ionic bond, the concerted hydrogen bond interactions can improve the cross-linking strength,³³ and their collective properties can promote the formation of hydrogels, especially supramolecular hydrogels.^23,87,89

Reversible cross-linking can be established between different polymer chains through hydrogen bonds. The hydrogen bonds dissociate at high temperatures while recombine at low temperatures.^88,89 Thus, hydrogen bonds can be used in the preparation of self-healing hydrogels. For example, the hydroxyl groups on polyvinyl alcohol (PVA) can form intermolecular hydrogen bonds, leading to the formation of self-healing hydrogels following repeated freezing–thawing operations.^89,90 Zhao et al.⁹¹ prepared a self-healing supramolecular hydrogel through hydrogen bonds between tertiary amide groups in polyvinylpyrrolidone (PVP) and phenol hydroxyl groups in gallic acid (GA) (Fig. 1A(a)). The presence of hydrogen bonds imparts the hydrogel with good tensile properties and injectability (Fig. 1A(b) and (c)). Hydrogen bonds can also be combined with other supramolecular interactions to prepare hydrogels with multiple cross-linking interactions or multi-networks. For example, we previously developed a heat shrinkable hydrogel by combining hydrogen bonds and host–guest interaction. In our hydrogel, the dual non-covalent cross-linking strategy, especially the hydrogen bonds, imparts it with good elasticity and self-healing properties.⁹² The similar synergistic strategies of multi-interaction will be demonstrated in more detail later.

Self-healing speed and self-healing efficiency are also important parameters of hydrogen bond-based self-healing hydrogels. Numerous studies have been conducted to study the self-healing properties of hydrogels based on these two parameters. Wang et al.⁹³ prepared a supramolecular hydrogel (Fig. 1B(a) and (c)) via hydrogen bonds between phenol hydroxyl groups on TA and carbonyl, hydroxyl and amino groups of hydrogel chains. The water in the hydrogel network can improve the fluidity of TA molecules and unsaturated hydrogen bonds, thus greatly improving the speed of self-healing (indicates a healing efficacy of 95%) (Fig. 1B(b)). Zhao et al.⁹⁴ prepared semi-interpenetrating polymer network hydrogels using sodium polyacrylamide (PAM) and alginate (SA). Based on the hydrogen bonds between PAM and SA molecules, the hydrogel had a rare self-healing ratio of 99% at room temperature.

In the field of hydrogels, the stimuli-responsive property has been a hot topic, because this property is closely related to many applications of hydrogels. Hydrogen bonds in supramolecular hydrogels can act as thermo-triggered regulators of mechanical behaviors, thus imparting shape memory properties to the hydrogels.^88,95,96 For example, Zhu et al.⁹⁷ prepared a fluorescent hydrogel with good shape memory properties and toughness. The dense and strong hydrogen bonds between carboxylic acid and imidazole groups make the hydrogel glassy at room temperature with moderate water content. In addition, hydrogen-bonded supramolecular hydrogels with stimuli-responsive expansion properties have also been reported. For example, Xu et al.⁵⁴ prepared a polysaccharide supramolecular hydrogel with self-healing and dual-responsive swelling properties by adding hymexazol into a mixed solution of alginate and carboxymethyl chitosan. Results showed that the increasing concentration of PBS could delay the water adsorption of hydrogels. Moreover, the swelling of the hydrogel increased with the pH value in a 0.1 M PBS solution.

Hydrogen bonds can also achieve adjustable self-healing performance and shape adaptivity by responding to external stimuli. Our team designed an injectable DN (double network) hydrogel, which consisted of catechol-Fe³⁺ coordination cross-linked poly(glycerol sebacate)-co-poly(ethylene glycol)-g-catechol (PEGSD) and quadruple hydrogen bonds cross-linked ureido-pyrimidinone modified gelatin (GTU). The tests confirmed the good self-healing efficiency of the hydrogels, partly due to quadruple hydrogen bonds between UPy motifs from GTU. Apart from injectability and self-adaptability, the quadruple hydrogen bonds and Fe³⁺-catechol coordination can also respond to heat (resulting in decreased cross-linking density) and NIR irradiation (with the rapidly rising temperature, fluidity of the hydrogel network increased rapidly, thereby significantly fastening the self-healing property)⁵² (Fig. 1C).

Hydrogen bonds can also be used as a method of strengthening hydrogel systems to endow hydrogels with a variety of other properties at the same time. For example, natural polymer TA can have hydrogen bond interaction with various polymers, such as PVA, polyethylene glycol (PEG) and gelatin.^44,98,99 Hydrogen bonds can also drive specific phase separation processes. Kamakshi Bankoti et al.¹⁰⁰ prepared a macroporous hydrogel scaffold under room temperature drying conditions. The intermolecular and intramolecular hydrogen bonds between chitosan and polyurethane diol dispersion (PUDs) are used to induce the phase separation process in the system. They studied the effects of phase separation on scaffold's degradation and mechanical properties, and concluded that it was suitable for wound healing (showing increased wound contraction, higher collagen synthesis and vascularization).^100,101 The applications of supramolecular hydrogels in wound repair can be found in Section 4.

In conclusion, since the mechanical properties of supramolecular hydrogels cross-linked by a single hydrogen bond are poor, the majority of research has concentrated on their exceptional reversible properties, such as self-healing, shape memory, and stimulus response. In contrast, supramolecular hydrogels cross-linked by multiple hydrogen bonds have better mechanical properties and can be combined with other non-covalent interactions. The theory of their reversible properties needs further study.

2.2 Electrostatic interaction

Electrostatic interaction is a force resulting from electrostatic attraction between ions or groups with opposite charges. Although electrostatic interaction is the reason for the formation of chemical bonds such as ionic bonds and metal ion coordination bonds, as a kind of non-covalent interaction, its bond energy is quite different from that of some common chemical bonds. Ions can interact with dipoles (polar molecules or groups), or induce nonpolar molecules to become polarized (induced dipoles). The electrostatic attraction between oppositely charged monomers, the interaction between cations (such as protonated amines) and anions (such as carboxylates and sulfates) in polymers, and the interaction between charged polymers and oppositely charged ions can all be driving forces for the formation of hydrogels.^23,89

The electrostatic interactions between polycations and polyanions can be used to form hydrogels.¹⁰² Numerous studies have shown that chitosan (CS), a positively charged natural cationic polymer, can form polyelectrolyte complexes with negatively charged polymers like polysaccharides (such as hyaluronic acid), proteins (such as gelatin) and synthetic polymers (such as polyacrylic acid).^23,103 For example, Zhang et al.¹⁰⁴ constructed a hydrogel using polycation CS, polyanion γ-PGA and heparin, and loaded superoxide dismutase (SOD) in the hydrogel to impart it with antioxidant properties. The hydrogel shows a good and connected porous sponge structure, which is conducive to the transfer of nutrients and the elimination of cell metabolites. With the increase in heparin content, the electrostatic interaction and cross-linking degree increased while the porosity of materials reduced.^102,104 Similarly, Lai et al.⁶⁴ developed a biodegradable polyelectrolyte hydrogel through the electrostatic interaction between CS (positively charged) and carmellose (negatively charged). Electrostatic interactions made the hydrogel preparation process simpler and more convenient by allowing the mixing of the two polymer solutions before application (Fig. 2A).

The researchers also explored the methods to improve the preparation of electrostatic interaction cross-linked hydrogels. Generally, the self-assembly of low-molecular-weight hydrogelators is triggered by a sol–gel process. External stimuli (such as temperature, pH, solvent change and chemical reactions) are able to adjust their solubility. Due to their weak solubility in water, peptides are typically induced to undergo self-assembly by first dissolving them in dimethyl sulfoxide (DMSO), followed by a subsequent dilution step in water and a change in pH, or alternatively, by heating the solution to enhance its solubility and subsequently cooling it. Miryam et al.⁵⁹ introduced a new preparation strategy of supramolecular hydrogel in their work, where they triggered and controlled the self-assembly of Fmoc FFpY peptides through direct electrostatic interaction with polycations, thus avoiding the dephosphorylation of peptides (Fig. 2B). Compared with the Fmoc FFpY hydrogel induced by enzymatic dephosphorylation, the obtained hydrogel showed enhanced mechanical properties on a large scale.

The phenolic group in polyphenols is partially ionized when the pH is higher than pK_a, resulting in a large number of negatively charged groups.¹⁰⁵ Based on this principle, polyphenols and cationic polymers (such as poly(dimethyldiallylamide) (PDDA)) and PNIPAm can be physically self-assembled in a layer-by-layer fashion to prepare supramolecular hydrogels or engineering scaffolds.^106,107 This process is the assembly of molecules with opposite charges on the substrate through electrostatic interactions between their surfaces.¹⁰⁸ The number of relevant studies in this field still accounts for a small proportion in the entire field of supramolecular hydrogel dressings. Although the preparation process is relatively simple, the conditions for selecting raw materials are quite strict: they must have a certain charge and good biocompatibility. In addition, charged polymers are sensitive to the surrounding environment (e.g., pH and ions), so reaction conditions are a key factor to consider.^109,110 Finally, a thorough assessment of the effect of electrical charge on the wound and its surrounding tissues is necessary to help understand the potential effects that these dressings face during actual use. With further research, more mature supramolecular hydrogel dressings based on electrostatic interactions will be developed. The application of electrostatic interaction cross-linked supramolecular hydrogels in hemostasis and wound healing is discussed Sections 5 and 6.

2.3 Hydrophobic interaction

Hydrophobic interaction plays a crucial role in the process of biological structures’ formation (such as the tertiary structure of proteins). The strength of this interaction surpasses that of hydrogen bonds and van der Waals interactions. The non-covalent hydrophobic interaction between non-polar hydrophobic groups can be used to drive the reversible hydrogel network.^23,111 For instance, copolymerization of acrylamide with n-alkyl acrylamide or n-alkyl methacrylate having alkyl chains ranging from 4 to 12 carbon atoms yields a tough hydrogel.^112,113

The hydrogel network formed through hydrophobic interactions typically consists of both hydrophobic and hydrophilic components. The amphiphilic molecular chain folds in water in such a way that the hydrophobic regions become the core while polar groups are exposed to surrounding water. When the minimum gelling concentration is reached, the molecules aggregate and form micelles, finally leading the formation of a hydrogel.^114,115 To this end, the commonly used micelle self-assembly technique can be used to incorporate hydrophobic sequences into amphiphilic polymer micelles. For example, our group prepared an injectable micellar-reinforced hydrogel with self-healing properties. The cross-linking agent PF127-CHO can self-assemble into micelles, and then cross-link with quaternary ammonium chitosan (QCS), resulting in a double-cross-linked hydrogel through dynamic Schiff base bonds and micellar cross-linking.¹¹⁶ Besides, the hydrophobic domains’ size, number and geometry will affect the mechanical properties of hydrophobic interaction cross-linked hydrogels, and their properties can also be modified by adding surfactants or salts. For instance, the water solubility of stearyl methacrylate (C18M) and alkyl acrylate (C22) is relatively low. However, their copolymerization with acrylamide in a micelle solution can be facilitated by the introduction of salt.^112,114

The reestablishment of hydrophobic interaction contributes to the exceptional self-healing performance of these hydrogels.^115,117 For example, Lei et al.⁶⁸ prepared a hydrogel based on silk fibroin through hydrophobic interaction (Fig. 3A(a)). The hydrogel achieved self-healing performance through reversible hydrophobic interaction between C18M and regenerated silk fibroin (RSF) at room temperature without external stimulation. The results of mechanical tests and rheological measurements showed that the hydrophobic interaction, acting as sacrificial bonds in the system, broke before the alginate–Ca²⁺ ion network under an external load, dissipating a lot of energy, and enhancing the mechanical elongation, strength and toughness of the hydrogel. In addition, due to the existence of hydrophobic interaction, the hydrogel can also quickly restore its structure after injection (Fig. 3A(b) and (c)).⁸⁹ However, the degradation rate of the hydrogel will decrease with the increase in C18M concentration, which may be an obstacle to the degradation process of the hydrogel.

Recently, Zhang et al.¹¹⁸ reported an injectable and self-healing hydrogel cross-linked by hydrophobic interactions (Fig. 3B(a) and (b)). The o-nitribenzyl ester group is cleaved under UV irradiation with the hydrophobic domain transforming into a hydrophilic one, leading to the effective release of doxycycline (DOX).^89,118 Both examples mentioned above are based on strong hydrophobic interactions, but weak hydrophobic interactions can also be applied to hydrogel structures. Jing et al.⁶⁷ prepared a PEG-DPCA supramolecular hydrogel. As a structure directing agent and therapeutic agent, DPCA (dihydrophenonthrolin-4-one-3-carboxylic acid) exhibits reversible weak hydrophobic interactions between its domains, which enables the hydrogel to flow under external shear stress, and fully recover to the gelled state immediately after the stress is relieved.^67,119

In addition, hydrogels formed through hydrophobic interactions usually exhibit a negative thermal response behavior (the rise of temperature leads to the hydrogel formation process). Generally speaking, the hydrophilic groups of macromolecules will undergo solvation by water molecules below the phase transition temperature, establishing hydrogen bonds with the surrounding water molecules. When the solution is heated, the mobility of water molecules increases, which destroys the solvated polymer chains and further promotes the formation of hydrogels.^89,120,121

In conclusion, hydrophobic interaction is an intermolecular interaction that occurs universally in the human body, and supramolecular hydrogels cross-linked by this reversible interaction can have injectable or self-healing properties. Besides, the hydrophobic domain in hydrogels based on hydrophobic interactions can be used to load drugs or active substances and it will be discussed in Section 4.1.3.

2.4 Host–guest interaction

The host–guest interaction is realized through the mutual recognition of “host” and “guest” molecules. It is based on the formation of a selective inclusion complex between the cavities of host molecules and smaller guest molecules (such as adamantine).^23,87 The shape and size complementarity between the host cavity and the guest molecules is crucial in this interaction. In this way, the host can pair with a variety of guest molecules which not only show a degree of inertness, but also respond to stimuli. In the hydrogel structure, the formation of the host–guest structure is relatively easy, which provides greater repeatability for the hydrogel performance. The reversible nature of host–guest interactions imparts hydrogels with the self-healing and shear thinning properties.^122,123

The host group encompasses a diverse array of naturally derived and synthesized macrocycles, as well as their derivatives. Cyclodextrin (CD) is the most prominent representative of hosts; it has a series of water-soluble and low-toxicity cyclic oligomers with 6, 7 and 8 truncated glucose units, which are called α-CDs, β-CDs and γ-CDs, respectively.^23,124 CDs have hydrophilic outer shells and relatively hydrophobic inner cavities, and the hydrophobic inner cavity can form inclusion complexes with various types of guests²³ like adamantane, azobenzene, ferrocene, cholesterol and polyethylene glycol.^103,125 Besides, CD units can also be grafted onto other polymer chains, such as alginate, HA and PEG. The guest molecule is subsequently linked to another polymer chain, thereby facilitating the formation of supramolecular hydrogel.^123,126 For example, Li et al.⁷⁵ developed a new strategy for the preparation of hydrogels: developing convertible nanoparticles through the self-assembly of hydrophobic and proton sensitive host materials (HCD) and hydrophilic guest macromolecules (8PEG-Ada). Hydrophilic host molecules released from hydrolyzed nanoparticles under acidic conditions can spontaneously assemble with guest molecules through enhanced host–guest interactions, thus producing hydrogels (Fig. 4A(a)). It is noteworthy that orally administered transformable nanoparticles can effectively mitigate ethanol or drug-induced gastric injury in mice by forming an in situ hydrogel barrier (Fig. 4A(b)). As mentioned in the first three sections of this chapter, supramolecular interactions can exist in hydrogels as standalone interaction segments, or they can be combined with a variety of other supramolecular interactions to achieve synergistic effects. Moreover, self-healing, injectable, good mechanical properties and other properties are usually associated with many functions, and the host–guest supramolecular hydrogels described in this section are no exception. Previously, our group developed a series of self-healing and injectable supramolecular hydrogels by utilizing quaternized chitosan-graft-cyclodextrin (QCS–CD), quaternized chitosan-graft-adamantane (QCS–AD), and graphene oxide-graft-cyclodextrin (GO–CD) as building blocks. This approach combines the excellent antibacterial activity of QCS with the photothermal properties of reduced graphene oxide (rGO) (Fig. 4B(c)). The hydrogels exhibit rapid recovery within 14 seconds, owing to a diverse range of dynamic non-covalent interactions including host–guest interaction and hydrogen bonding among QCS–CD, QCS–AD, and GO–CD (Fig. 4B(b)).⁷² In addition, we also prepared a supramolecular hydrogel, which is composed of silk fibroin (SF), acryloyl-β-cyclodextrin (Ac-CD) and 2-hydroxyethyl acrylate through photopolymerization. Host–guest interactions and the hydrophobic β-sheet configuration are used to achieve a dual cross-linked hydrogel with good mechanical properties, rapid self-healing, injectability and good biocompatibility, which is conducive to wound healing (Fig. 5A(a) and (b)). It is worth noting that the self-healing process of our hydrogels can be completed quickly without any additional rest time, which makes them highly competitive among other physical hydrogels, because it usually takes several minutes or hours for traditional physical hydrogels to restore their original properties.¹²⁷

As an indispensable cross-linking medium in traditional covalent hydrogel networks, chemical cross-linking agents are generally difficult to use in the cross-linking process of supramolecular hydrogels.¹²⁸ In recent years, the emergence of a new type of cross-linking agent, the supramolecular cross-linking agent, has paved the way for scientific researchers, and has been gradually applied in the development of supramolecular hydrogels.¹²⁹ Yang et al.⁶⁹ prepared a self-healing supramolecular hydrogel by cross-linking acrylamide with a cross-linking agent assembled from poly(β-cyclodextrin)nanogel and azo phenylacrylamide. Photoisomerization of azobenzene can change its relationship with β-cyclodextrins, so that the cross-linking density and rheological properties of hydrogels can be adjusted by external light stimulation. It is also worth mentioning that damaged hydrogels lose their self-healing ability under ultraviolet irradiation, but can restore their self-healing behavior under visible light irradiation. The switchable self-healing properties are innovative, combining the properties of supramolecular networks with the concept of stimulus response.^69,127,130 Similarly, Zhou et al.⁷⁷ prepared a supramolecular hydrogel with self-healing properties and injectability by using a “supramolecular cross-linker” method (Fig. 5B(a)). The star supramolecular cross-linking agent is formed through the host–guest interaction between octa-cyclodextrin polyhedral oligomeric silsesquioxane (OCDPOSS) and acrylamide-modified adamantane (Ad-AAm). Subsequently, the host–guest interaction in the cross-linking agent became the actual cross-linking mechanism for hydrogels by means of co-polymerization. The multivalent host–guest interactions in the hydrogel improves its ductility, rapid self-healing and injectability. Simultaneously, the incorporation of rigid polyhedral oligomeric silsesquioxane as a supramolecular cross-linker endows supramolecular hydrogels with remarkable mechanical properties (Fig. 5B(b)).

In essence, supramolecular cross-linkers function as “intermediaries” in non-covalent cross-linking, combining the concept of “cross-linkers” in chemical hydrogels with non-covalent interactions. The emergence of supramolecular cross-linkers mitigates the adverse effects of toxic cross-linkers to a great extent, and offers a fresh approach for the creation of supramolecular hydrogels.

Thanks to the stability of the main part of the host–guest structure, its excellent molecular recognition ability and the ease of binding with guest molecules, researchers have utilized host–guest interactions to prepare hydrogels with self-healing, adhesion, and excellent biocompatibility, which have found widespread application in the field of wound dressings. However, many challenges and unmet needs remain. Most host–guest supramolecular hydrogels are produced at the laboratory level. The synthetic routes and post-processing procedures of materials are usually quite complex, and the reproducibility of experimental steps is poor, which greatly hinders their clinical conversion.^131,132 On the other hand, the in vivo long-term toxicity of various host or guest chemical agents in supramolecular hydrogels is also a key issue that needs attention at this stage and is closely related to dressing removal (avoiding mechanical removal of dressing) and application safety (preventing the accumulation of toxic components over time).¹³³ On the basis of the summary of previous research results and in-depth future studies, the application of host–guest supramolecular hydrogels in wound repair and hemostasis can be constantly improved by optimizing the structural design ideas, identifying and investigating potential problems.

2.5 Metal–ligand coordination

Chelation is a special interaction, which is based on two or more independent binding sites of a central atom on the same ligand. This chemical entity is called a chelate, and this interaction is called chelation interaction.¹³⁴ In the coordination bond, multiple donor groups (ligands) may participate in the process of bonding with the central metal ion. Because it offers the full structure of metalloproteins and the catalytic centers of many enzymes, coordination chemistry is essential to biological systems. The strength of coordination bonds varies widely, and it can be equal to or even higher than that of covalent bonds, depending on the type of ligand and the properties of metal ions.¹³⁴ But at the same time, metal coordination bonds are dynamic and reversible compared with covalent bonds. Various organic or inorganic ligands can combine with metal ions to form linear, branched or star-shaped complexes.^23,134 Compared with other non-covalent bonds¹³⁵ or dynamic covalent bonds, metal ligand coordination binding is unique in that biomaterials prepared through this interaction can have multiple wound healing functions when introducing inorganic particles and ions with inherent physical and chemical properties (such as antibacterial and anti-inflammatory function).^136,137 The function of promoting wound repair associated with metal coordination will be discussed in detail in Sections 4 and 5.

Hydrogels based on the coordination between metal ions and ligands are mainly obtained by functionalizing the polymer skeleton through chelating ligands.^134,138 There are many kinds of ligands used to prepare supramolecular adhesion hydrogels, such as iron ion and catechol ligands.¹³⁹ The complex is found in the adhesion protein of mussels, and it provides strong adhesion for different wet surfaces. For example, our group prepared a DN supramolecular hydrogel under physiological conditions, and endowed it with functions such as resistance to drug-resistant bacteria and promotion of skin repair. The first network of hydrogels is formed by catechol–Fe³⁺ coordination cross-linking. In addition to dynamic cross-linking, the network can also provide a variety of functions such as stimulus response, photothermal ability, tissue adhesion and free radical scavenging ability.⁵²

Some modified products of chitosan, such as quaternary ammonium chitosan (QCS) and carboxymethyl chitosan (CMCS), are often used as matrix substances to construct metal coordination bonds. For instance, our group has previously developed an injectable and self-healing Mg-QCS/PF composite hydrogel capable of sustaining the release of Mg²⁺. Within the hydrogel structure, the hydroxyl groups and amino groups on the QCS main chain can form metal coordination bonds with divalent magnesium ions. The self-healing properties of QCS/PF hydrogels enhance the safety profile for their application in tendon sheath repair. Furthermore, it is noteworthy that this hydrogel exhibits improved stability at the tendon–bone interface due to its adhesive characteristics.^116,140 CMCS has abundant coordination groups and groups which can generate hydrogen bonds. It has a class of naturally occurring ligands that can coordinate with metal ions, and has significant potential in various fields. For example, in the research conducted by Cao et al.,⁸⁶ Fe³⁺ and Al³⁺ can form coordination bonds with CMCS that is uniformly dispersed in the alkali/urea aqueous solution for an ultrafine gelation process (Fig. 6A(a)). Due to the dynamic and reversible properties of metal coordination bonds, hydrogels have self-healing, adaptive and thermal response capabilities (Fig. 6A(b)).⁸⁶ In addition, owing to a series of excellent characteristics of metal ligand coordination, it is often applied in multi-cross-linked and multi-network supramolecular hydrogels. Yan et al.¹⁴¹ presented the concept of multiple metal ions participating in coordination (Fig. 6B(a)). They successfully prepared a DN supramolecular hydrogel through strong coordination interaction between CMCS and various metal ions (Cu²⁺, Zn²⁺, Ni²⁺, Co²⁺, Fe³⁺ and Cr³⁺) (Fig. 6B(b)). Hydrogen bonds and metal coordination interaction are functionally independent and reversible, which makes the programming of hydrogels multifunctional, including the pH regulated shape memory behavior and multi-stage self-healing properties. Wu et al.¹⁴² prepared a tough double non-covalent cross-linking network hydrogel (Fig. 6C(a)). The rigid CS-ionic network is used as the first network while the pectin network cross-linked by Fe³⁺ is used as the second network of the hydrogel. The experimental results demonstrate the hydrogel's exceptional toughness (1.04–11.20 MJ m⁻³) and adjustable mechanical properties (tensile strength: 0.97–1.61 MPa, elongation: 133–1346%, elastic modulus: 0.30–2.20 MPa) (Fig. 6C(b)). Zhang et al.¹⁴³ thought that in situ polymerization of conductive precursors into a polymer matrix can be a simple and effective method to improve the uniformity of silly putty-like materials. Consequently, a series of supramolecular hydrogels exhibiting excellent self-healing capabilities and photothermal conversion properties were synthesized through the utilization of metal–ligand interactions and hydrogen bonds. The incorporation of coordination bonds between Fe³⁺ and phytate polyvinyl alcohol (PPVA) imparts unique rheological characteristics to the hydrogels, including shear thinning behavior (Fig. 6D(a) and (b)).

Metal ligand-based supramolecular hydrogel dressings are still in their infancy. Due to the presence of metal ions and reversible coordination, these hydrogels can exhibit inherent antibacterial properties, electrical conductivity, and the ability to deliver active substances. Although they have been used as wound dressings or hemostatic materials, they also face many challenges. For example, the toxicity of metal ions should be considered when introducing them, and the commonly used metal ions are usually more toxic. We believe that following are the possible solutions to this problem: (1) change their forms (such as transforming them into metal nanoparticles), which will reduce the toxicity of metal ions in hydrogels and (2) select less toxic metal ions or biologically active metal ions (such as Mg²⁺ and Zn²⁺).¹⁴⁴ On the other hand, when designing hydrogels, researchers mainly use natural polymers (such as gelatin and hyaluronic acid) or biocompatible synthetic polymers (such as polyethylene glycol). However, predicting the biocompatibility following the introduction of chelating ligands poses challenges due to the involvement of macromolecules and essential metal ions in biochemical reactions within the body, and their coordination with ligands may potentially impact endogenous biochemical processes.¹⁴⁵ Therefore, for application in wound repair and hemostasis, the supramolecular hydrogels based on metal ligand coordination still have a long way to go and need further in-depth study.

2.6 Other interactions

In addition to the five common non-covalent cross-linking interactions described above, several uncommon non-covalent interactions have also been used in the cross-linking strategies of supramolecular hydrogels. Cation–π interaction is a non-covalent interaction arising from the mutual attraction between a cation and an aromatic system, and it is stronger than other π interactions (such as π–π interactions), so we can consider this interaction as a new method to control the polymer region and stereoselectivity. Many studies have proved this feature, and it exhibits synergistic effects with some substances, which is particularly important for the structural design of hydrogels with self-healing and injectable properties.^146–148 For example, inspired by barnacle bone cement protein, Ni et al.¹⁴⁹ combined cationic structure modified polyphosphazene with polyvinyl alcohol to prepare a series of dynamic viscous hydrogels. The cation–π interaction in the hydrogel further enhances the inherent interfacial toughness and cohesion of polymer chains, enabling stable adhesion to various wet tissue surfaces. In addition, π–π stacking (existing in the poly(N,N-dimethylethylenediamine-g-3-bromomethylphenylboronic acid)phosphazene chain) and cation–π interactions also enable the hydrogel to undergo rapid self-repair when damaged.

Protein–protein interaction generally refers to the specific contact between proteins through molecular docking in a specific biological system. It can be divided into two types: direct contact between protein molecules, and complexation among proteins and other intermediates. It is worth noting that the stability of protein is not the same at different pH values due to its pH charge dependent ionizable groups, which makes it a key factor to consider in practical applications.^150–153

In general, hydrogels cross-linked by multiple hydrogen bonds have mechanical properties comparable to those of covalent cross-linked hydrogels. Most supramolecular hydrogels constructed through hydrogen bonds have self-healing characteristics and some of them can also acquire shape memory properties; electrostatic interactions can be used to prepare self-healing supramolecular hydrogels, achieve drug delivery functions and improve the cross-linking degree of hydrogels; the hydrophobic domain in hydrogels based on hydrophobic interactions can be used to load drugs or active substances. Supramolecular hydrogels based on hydrophobic interactions can exhibit self-healing, stimulus response and other relative characteristics. They can also be used to enhance the mechanical properties of hydrogels, such as mechanical elongation, strength and toughness; the supramolecular hydrogel prepared via host–guest interaction has the characteristics of self-healing and shear thinning, which can also be used to increase the cross-link density of the hydrogel and correspondingly improve some mechanical properties; metal ligand coordination can be used to fabricate self-healing and stimuli sensitive supramolecular hydrogels, and can combine hydrogels with other excellent properties, such as building drug controlled release systems according to different intrinsic properties of various coordination bonds.

With advancements in research on supramolecular hydrogels, researchers have gained a deeper understanding of existing non-covalent cross-linking methods, and more and more non-covalent interactions will be introduced into the structure of supramolecular hydrogels. We expect that future work will facilitate the design of better supramolecular hydrogels. Some properties of hydrogels (rheological properties and mechanical properties) will be improved by regulating the non-covalent force and the cross-linking structure of hydrogels, and these hydrogels can be endowed with more intelligence.

3 Network structures of supramolecular hydrogels

It is well known that the structure of a material determines its properties, which is also suitable for hydrogels. The network structure design of a hydrogel affects a series of properties, so different properties of hydrogels are attributed to different types of network structure. This section will commence with an exploration of the network design of supramolecular hydrogels, aiming to elucidate the intricate relationship between the network structures and the properties exhibited by these hydrogels. We divide supramolecular hydrogel network structures into single, double and triple network structures, and they are described and discussed in detail, aiming to stimulate further thinking among readers. Table 2 lists three different network types of supramolecular hydrogels.

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3.1 Single network supramolecular hydrogels

A hydrogel which is connected by a cross-linking agent or relies on only one cross-linking interaction and has one single 3D network is called a single cross-linked single network hydrogel.¹⁷³ When the cross-linking in these hydrogels is based on noncovalent interactions, we call them single cross-linked single network supramolecular hydrogels in the review. Compared with traditional chemically cross-linked hydrogels, single cross-linked single network supramolecular hydrogels exhibit superior performance in some aspects (such as self-healing, injectability, shape memory properties and stimulus responsiveness). For example, supramolecular hydrogels prepared by Jing et al.⁶⁷ through hydrophobic interactions promote tissue regeneration while possessing many attractive properties: simple injection, shear thinning and high drug-carrying. However, because of their single cross-linking mode and network structure, non-covalent cross-linked hydrogels may also exhibit disadvantages (poor mechanical properties). With the introduction of the concept of dual networks and multi-networks, and the development of multifunctional, multi-crosslinked and composite hydrogels, some defects of single cross-linked single network supramolecular hydrogels can be addressed.

When macromolecules are connected by two or more than two cross-linking interactions (or cross-linking agents), the network structure is called a multi-cross-linked network structure.¹⁷³ A double cross-linked single polymer supramolecular network is mainly a single network structure containing two different, dynamic and noncovalent cross-linking interactions. This allows them to compensate multiple stimuli, and provides better mechanical properties than single cross-linked polymers. Even so, their mechanical properties can still be improved a lot, which will be discussed in comparison with other structures later. Double cross-linked single network supramolecular hydrogels can be constructed through any combination which consists of two kinds of supramolecular interactions, and the two types of noncovalent cross-linking interactions may exhibit sensitivity to two different stimuli.^173,174 For example, Song and his colleagues¹⁵⁴ developed a self-healing cordycepin (CY)/CS supramolecular hydrogel dressing, which was prepared through hydrogen bonds and electrostatic interactions without any cross-linking agents. The hydrogel has an appropriate swelling ratio and self-healing properties, and can fill irregularly shaped wound defects without the need for preforming, due to the network's synergy between hydrogen bonds and electrostatic interactions. Similarly, Azadikhah et al.¹⁶⁰ prepared a double cross-linked supramolecular hydrogel by using the freeze–thaw method based on hydrogen bonds and metal coordination. TA molecules act as a cross-linking agent by establishing multiple hydrogen bonds between polymer chains and coordinating with Fe³⁺ to further connect them (Fig. 7A(a) and (b)). The hydrogel has a double cross-linked network structure, which endows it with good mechanical properties, injectability, self-healing and shear thinning properties.

In view of the limitations of silk fibroin hydrogel, such as long gelling time, high temperature and lack of self-healing, our team prepared a supramolecular hydrogel using 2-hydroxyethyl acrylate, acryloyl-β-cyclodextrin (Ac-CD) and SF. Unlike other methods of grafting CD onto SF through complex steps, this method can integrate the advantages of SF, Ac-CD and Cur into one system by simply modifying the original SF and CD. Ac-CD was selected as a host molecule while the aromatic amino acids of SF was selected as a guest molecule, and the second polymer skeleton was formed by the polymerization of Ac-CD and 2-hydroxyethyl acrylate (HEA) (Fig. 7B(a)). Double cross-linked hydrogels through host–guest interactions and a hydrophobic β-sheet configuration (hydrophobic interaction) exhibit long-term stability, rapid self-healing properties (Fig. 7B(b)), injectability and good biocompatibility, which was conducive to its application as a wound dressing.¹⁴

A multi-cross-linked single supramolecular network is usually a single network structure formed by more than two different non-covalent cross-linking interactions. The concept of multi-cross-linking is based on single cross-linking and double cross-linking, so that the types of cross-linking in the structure of multi-cross-linked networks are relatively more complex, which indirectly leads to the complexity and flexibility of the synergies between these cross-linking modes.¹⁷⁵ For example, Qi et al.⁵⁶ prepared a tough supramolecular hydrogel (Fig. 8A(a)) by modifying hydrophilic poly(acrylic acid) (PAA) with a little of hydrophobic lauryl methacrylate (LMA) in the presence of cetyltrimethylammonium bromide (CTAB). Due to the synergistic effects of electrostatic and hydrophobic interactions between CTAB and the P(AA-co-LMA) copolymer, the hydrogel exhibits exceptional resistance to swelling with a water content of 58.5 wt%. Additionally, it demonstrates remarkable tensile strength (approximately 1.6 MPa), high stretchability (>900%), and rapid self-recovery at room temperature (around 3 minutes at 100% strain) (Fig. 8A(b)). Wang et al.¹⁷⁶ prepared SPU-PAA/Zn self-healing hydrogel films (Fig. 8B(a)). The synergistic effect of coordination interaction (between sulfonate groups of SPU and Zn²⁺, carboxylic acid groups of PAA and Zn²⁺) and hydrogen bonds (between carboxylic acid groups of PAA and urea as well as urethane groups of SPU) in the network and the enhancement effect of hydrophobic domains formed in situ greatly improve the mechanical properties of the hydrogel. Meanwhile, these multiple non-covalent cross-linkages also impart it with self-healing and elastic properties (Fig. 8B(b)). Deng et al.¹⁶³ developed a supramolecular hydrogel with antibacterial properties using Al³⁺ and alginate–dopamine (Alg-DA) chains to cross-link with the copolymer chains of acrylamide and acrylic acid (PAM) through triple dynamic noncovalent interactions (hydrogen bonds, metal coordination, and electrostatic interaction). It is worth noting that the hydrogel can be easily recycled in a pollution-free manner, thanks to the synergy of three non-covalent interactions and setting it apart from other hydrogels with a similar structure. Furthermore, the hydrogel exhibits remarkable advantages in terms of cellular and tissue affinity as compared to other hard and antibacterial hydrogels, which is typically harmful to cell growth, owing to the presence of Alg-DA, so that it has high application potential in repairing soft tissue and preventing bacterial infection of wounds. The application of multi-cross-linked single network hydrogels in wound repair and hemostasis will be discussed in Chapters 4 and 5.

3.2 Double network supramolecular hydrogels

The traditional double network (DN) hydrogel consists of interpenetrating networks (IPNs) synthesized and infiltrated by two different polymer components in turn to form the whole system.^177,178 The first network is a highly cross-linked polyelectrolyte that serves as a rigid support to maintain its shape, while the second network is a loosely cross-linked flexible neutral polymer used as a filler to absorb external stress. Therefore, DN hydrogel showed both rigidity and softness.^177,179 Under conditions of large deformation, the rigid network dissipates energy through cross-linked fracture, while the flexible network remains relatively intact, which endows the hydrogel with the ability to recover from deformation to a certain extent. Therefore, the combination of these two different types of networks enhances the mechanical properties, and the resulting hydrogels also show different types of mechanical response properties.^180–182 Compared with DN hydrogels synthesized using two covalent cross-linking networks,^178,181,183 the DN hydrogels prepared with partial or complete non-covalent cross-linking exhibit greater toughness.^178,184 The rupture of the non-covalent bonds absorbs mechanical energy, improve toughness, and the broken bond can also be restored to rebuild the structure of the hydrogel.^185,186

Although biomedical applications require high strength, high toughness and self-healing properties, traditional concepts hinder the possibility of coexistence of these different properties in DN hydrogels. Moreover, the use of toxic initiators and acrylamide-based monomers is not feasible. In addition, when considering the operation of hydrogel in tissue engineering, the injectability of DN hydrogel is also an important factor affecting the performance of hydrogel.¹⁸⁷ Different from the multi-cross-linked single network supramolecular hydrogels introduced in the previous section, the two networks in DN supramolecular hydrogels can not only synergistically enhance the performance of hydrogels, but also exist independently, each dominating different performance of hydrogels and being endowed with corresponding functions.¹⁸⁸ For example, Xia et al.¹⁶⁹ fabricated a DN multi-functional supramolecular hydrogel for wearable strain sensors (Fig. 9A(a)). The polyacrylamide (PAAm) network is cross-linked by hydrophobic interactions, and the CS network is cross-linked by the electrostatic interaction of carboxyl-functionalized multi-walled carbon nanotubes (c-MWCNTs). The interconnection between these two networks is further reinforced through physical entanglement and the formation of hydrogen bonds. These cross-links work together to endow the hydrogel with excellent stretch and puncture resistance. In the CS network, the presence of CS endows hydrogels with enhanced self-adhesion behavior, and the introduction of c-MWCNT endows the hydrogels with superior strain-sensitive conductivity (Fig. 9A(b)). Similarly, Zhao et al.¹⁶⁵ reported a DN supramolecular hydrogel with injectability and self-healing properties (Fig. 9B(a) and (b)). When the temperature is above the critical gel temperature, the heat responsive polymer segment drives dehydration and the hydrophobic interaction, causing the polymer chain to become entangled with the first network. At the same time, non-covalent interactions between benzaldehyde groups will be formed, including hydrogen bonds, hydrophobic interactions and π–π interactions as the second network. When the benzaldehyde content increases from 0 to 8.2 mol%, the critical gel temperature of the hydrogel decreases significantly from 35.5 °C to 19.9 °C, while concurrently exhibiting a substantial increase in the storage modulus from 21 Pa to 1411 Pa, which indicates that the critical gel temperature and storage modulus of hydrogels are only controlled by the second network in the structure. In order to enhance the therapeutic effect of hydrogels on damaged tissues, Dong et al.¹⁵⁶ fabricated a series of composite hydrogels based on hydroxybutyl chitosan (HBC) and methacrylate sulfonated betaine with heat sensitivity, self-healing properties, and antibacterial activity (Fig. 9C(a)). The methacrylate sulfonated betaine network and the hydrophobic interaction cross-linking HBC network are cross-linked by electrostatic interaction to form a fully non-covalently cross-linked double network structure. The existence of the methacrylate sulfonated betaine network can promote the sol–gel transition of HBC. The HBC network has good killing activities against very few bacteria adhering to the surface of the material. The synergistic effect between anti-protein adhesion ability of the methacrylate sulfonated betaine network and the bactericidal ability of the HBC network makes hydrogels contributes to the good synergistic antibacterial performance of hydrogels. In addition, hydrogels do not need contain any cross-linking agents (Fig. 9C(b)).

Supramolecular double-network structures are also commonly used by researchers as basic structures to better enshrine the corresponding functions of hydrogels. DN supramolecular hydrogel sensors are a good example. Zhang et al.¹⁶⁶ fabricated a supramolecular hydrogel of poly(sulfobetaine-co-acrylicacid)/chitosan-citrate (P(SBMA-co-AAc)/CS-Cit) through the utilization of electrostatic interaction and hydrogen bonds between polymer chains (Fig. 9D(a)). The hydrogel exhibits high tensile strength, transparency, fatigue resistance, self-adhesive and good self-healing performance (Fig. 9D(b)). The self-healing efficiency reaches an impressive 95.4%. Furthermore, the hydrogel exhibits high sensitivity to a wide range of strains, making it suitable for use as a strain sensor capable of detecting joint movements such as bending and swallowing.

Thermosensitive hydrogels have always been the key objects for the functionalization of supramolecular hydrogels, especially multi-network supramolecular hydrogels, because of their characteristic of responding to external temperature changes. However, the majority of temperature-sensitive hydrogels reported to date are based on synthetic amphiphilic copolymers. Nevertheless, these synthesized copolymers lack biological activity, while agarose hydrogel exhibits a high melting temperature and chitosan can only be dissolved in acidic solvents. Moreover, physical gelatin hydrogel is unstable at body temperature and demonstrates low strength and poor stability similar to other single network supramolecular hydrogels. These problems greatly hinder the application of sports-related skin tissue healing.^189,190 In view of the above restrictions, our team utilized poly(glycerol sebacate)-co-poly(ethylene glycol)-g-catechol (PEGSD) and ureido pyrimidinone-hexamethylene diisocyanate (UPy-HDI) modified gelatin (GTU) as raw materials in 2020. By exploiting the catechol–Fe³⁺ coordination between PEGSD and Fe³⁺, along with the quadrupole hydrogen bonds of GTU, we successfully fabricated a supramolecular DN hydrogel exhibiting rapid shape adaptability, swift self-healing, and responsiveness to near-infrared/pH stimuli. As a kind of synthetic branched macromolecule, PEGSD can endow hydrogel with good flexibility, while the catechol groups on it can coordinate with Fe³⁺, resulting in dynamic cross-linking, NIR/pH-responsiveness, photothermal capacity, tissue adhesiveness and free radical scavenging. The gelatin (GT) network can promote tissue regeneration, and the UPy groups on the GT backbone can provide the second non-covalent network. Furthermore, the hydrogen bonds and the catechol–Fe³⁺ coordination can respond to photothermal and/or acidity. When exposed to NIR radiation and/or the acid solution wash, the hydrogel dressing can be easily removed.⁵²

Overall, after the mechanical properties of DN supramolecular hydrogels are enhanced, a variety of functions can be incorporated into them. In contrast to previous research, our work has endowed the hydrogel with a number of excellent reversible properties (on-demand removable tissue adhesion, dual stimulation response, rapid shape adaptation and self-healing) and multiple functions of promoting wound-healing (antibacterial, antioxidant, and angiogenesis promotion function), all while satisfying the high strength of the hydrogel network.

3.3 Triple network supramolecular hydrogels

Triple network hydrogels are a kind of multi-network hydrogel. They are similar to DN hydrogels, but show a more complex relationship among their networks. In previous studies, multi-network technology has been widely used to prepare hydrogels with excellent performance.^171,191 A variety of non-covalent interactions described in Chapter 2 can be introduced into the structure to construct triple network compound hydrogels. For example, Dai et al.¹⁹² designed a triple network hydrogel with physical and chemical double cross-linking. The first non-covalent network is constructed by utilizing the hydrogen bonds and related entanglement between the hydroxyl groups of PVA chain as the cross-linking point. Then, the PVA chain reacts with borax to form reversible diol-borax coordination bonds, forming the second network. Finally, the PVA crystal domain generated through the freeze–thaw cycle is used to form the third network. The experimental results show that the triple cross-linked network structure provides reliable and stable recovery performance and self-healing ability without any external stimulation.^192,193 Moreover, it is still difficult to achieve a shape memory hydrogel with multi-networks, multi-stimuli response and multiple shape memory effects with three-dimensional deformation at the same time. Wang et al.¹⁹⁴ developed a simple method to prepare a triple-network SMH. Their hydrogel consists of a stable chemically cross-linked PVA network, a reversible ion cross-linked CMCS–Fe³⁺ network and a hydrogen bonded PVA network. The shape memory behavior triggered by Fe³⁺, heat and near-infrared light was realized by using the coordination interaction between CMCS and Fe³⁺ and the stable temporary shape of reversible hydrogen bonds formed by PVA-OH.

However, due to the existence of chemical cross-linking in the structure, although the composite triple network hydrogels listed above have better mechanical properties and stability, their dynamic properties such as self-healing effects and injectivity may be weakened. Because chemical cross-linking networks are more likely to interact with the surrounding material, the bonds formed tend to be strong. The emergence of triple network supramolecular hydrogels provides a feasible solution to this problem.

Triple network supramolecular hydrogels add a new network to the foundation of DN supramolecular hydrogels, enhancing their designability, but the relationships and interactions between networks become more complex at the same time. Thanks to the strength and stability of the triple network itself, the triple network supramolecular hydrogels can even have the obvious advantages of single network and DN supramolecular hydrogels in some aspects without the need for any reinforcement means. For example, Pan et al.¹⁷² utilized Al³⁺ and carboxymethyl chitosan nanoparticles to cross-link PAA chains via metal coordination interaction, hydrogen bonds, and electrostatic interaction, resulting in the preparation of supramolecular hydrogels with noncytotoxic properties (Fig. 10(a) and (b)). Benefiting from the strong triple noncovalent cross-linking network and the dynamic nature of non-covalent bonds, the hydrogel shows ideal mechanical properties (Fig. 10(d)) (a breaking strength of 190.9 kPa and a breaking elongation of 1930%) and excellent self-healing properties (Fig. 10(c)) (a stress healing efficiency of 92.9% and a strain of 98.8%, 25 °C, healing for 24 h), and will not be significantly disturbed by surface aging or erosion (such as acid, alkali and salt solutions). What is striking is that due to the complete non-covalent cross-linking structure, the prepared hydrogel is also easily recycled in a pollution-free manner. Similarly, Jing et al.¹⁷¹ synthesized a triple network supramolecular hydrogel. The first network comprises a PAA-Fe³⁺ hydrogel, which is formed through metal coordination between carboxyl groups and Fe³⁺. The second and third networks consist of a gelatin hydrogel and PVA hydrogel, respectively, formed via hydrogen bonds. The non-covalent cross-linking networks can provide PAA-Fe³⁺/gelatin/PVA with good extensibility and shape recovery properties (Fig. 11(a)). Compared with single network and DN hydrogels, PAA-Fe³⁺/gelatin/PVA triple network hydrogels have better toughness, strength and recovery capacity, and their mechanical properties can be dynamically changed by adjusting their composition (Fig. 11(b)). The triple network supramolecular hydrogel exhibits excellent self-healing performance, with a remarkable healing efficiency exceeding 95% (Fig. 11(c) and (d)).

At this point, we can sum up the traits of various network structures found in supramolecular hydrogels and the connections between them as follows. Single network supramolecular hydrogels typically have poor mechanical characteristics, but these characteristics can be improved. Most single network supramolecular hydrogels have very good reversible properties due to their relatively weak cross-linking. Multi-cross-linked single network hydrogels, on the other hand, have cross-linking combinations that are more varied and flexible, allowing them to respond to various stimuli while also having better mechanical properties. The mechanical properties of DN hydrogels have been somewhat enhanced (double three-dimensional structure) compared to single network supramolecular hydrogels. The designability of the structure has been greatly enhanced by the ability of the two networks to either work together synergistically or separately. Finally, triple network supramolecular hydrogels are among the best in terms of mechanical properties, designability and reversibility; however, the relationships and interactions between the networks have grown more complex, raising the bar for research in cross-linking, network design, and raw material selection.

4 Application of supramolecular hydrogels in wound repair and hemostasis

4.1 Application of supramolecular hydrogels in wound repair

The situation of the wound and its surroundings is very complex, and the wound healing process is affected by many internal and external factors.⁸ As a unique member of the hydrogel family, supramolecular hydrogels have shown unprecedented potential and advantages in the field of wound dressings. In this section, the application of supramolecular hydrogels in wound healing will be discussed in detail from six aspects: antibacterial ability (Table 3), tissue adhesion (Table 4), substance delivery, anti-inflammatory and antioxidant function, function of cell control, angiogenesis promotion (Table 5) and other functions. Specifically, starting from the mechanism behind each function, we will classify and discuss the common function implementation methods, and then evaluate and summarize them.

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4.2 Application of supramolecular hydrogels in hemostasis

Hemostasis is the first step of wound healing and it is a self-repairing mechanism through which the body performs blood coagulation and platelet aggregation to prevent bleeding due to vascular injury or microvascular injury, such as vasoconstriction, platelet aggregation, coagulation, and fibrinolysis. Besides, abnormal platelet count, coagulation factor dysfunction, vascular wall function problems and other common factors can affect the normal physiological hemostasis process. Therefore, the development of wound dressings with hemostatic functions is quite important to prevent the rapid bleeding. Our group has conducted many explorations in hemostatic hydrogels and other hemostatic biomaterials,^283,284 including a systematic review of hydrogels for wound healing and hemostasis.⁸ In these articles, we systematically elaborated the whole process of wound repair and the specific repair mechanism at each stage, and objectively analyzed the design ideas, hemostatic principles and application limitations of hemostatic hydrogels from a variety of clear perspectives.

Different from our previous reviews mentioned above, this section mainly reviews the application of supramolecular hydrogels in hemostasis. On the premise of reasonable classification of hemostatic function, we analyzed the hemostatic mechanism of various hemostatic supramolecular hydrogels/hydrogel dressings. In short, the two main methods of obtaining and promoting hemostasis for supramolecular hydrogels are physical plugging and coagulation promotion. The two types of physical blocking hemostasis are achieved through hydrogel adhesion and hydrogel expansion, respectively. The three mechanisms of promoting coagulation are controlling the behavior of associated cells (such as platelets and blood cells), starting the coagulation process in vivo and interacting with coagulation factors. The more in-depth branches of the hemostatic concepts of physical plugging and coagulation promotion will be covered in detail in this section, along with assessment of earlier works. Table 6 lists a series of supramolecular hydrogels for hemostasis.

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4.3 Application strategies and removal of supramolecular hydrogels

5 Conclusions and prospect

5.1 Conclusions

Supramolecular hydrogels based on single or variety of non-covalent interactions (including hydrogen bonds, hydrophobic interaction, electrostatic interaction, metal ligand coordination and host–guest interaction) have many characteristics that are worthy of in-depth study. Because of these reversible non-covalent interactions, supramolecular hydrogels themselves have many properties closely related to the field of wound healing, including but not limited to self-healing, tissue adhesion and sensitivity to stimulation. These unique properties provide more possibilities for the application of supramolecular hydrogel dressings. In recent years, these hydrogels have demonstrated some excellent performances which can meet the various needs of wound repair, such as antibacterial properties, substance delivery, anti-inflammatory and antioxidant functions. Researchers have further promoted the development of future supramolecular hydrogel dressings by constantly innovating and combining raw materials, supramolecular cross-linking methods and enhancement means to meet more diverse and stringent requirements in the future. In this paper, several main cross-linking methods of supramolecular hydrogels are described in detail first, including some innovative and practical high-quality research work in the whole process from preliminary discussions, material selection to hydrogel preparation and characterization, which laid a solid foundation for further research studies and innovations in the field of supramolecular hydrogel dressings. Second, we systematically classified and summarized the network structures of supramolecular hydrogels. This review mainly introduces the applications of supramolecular hydrogel dressings in wound repair and hemostasis. Specifically, we have strictly divided the functions of hydrogels into promoting wound repair and hemostasis, and systematically described hydrogel cross-linking strategies, structural characteristics and the mechanism of action for each function, aiming to present a more comprehensive overview of the applications of supramolecular hydrogel dressings in the above two aspects for readers. In addition, we also present the future prospects of supramolecular hydrogels in structure (cross-linking strategies and network design) and the above two applications (wound repair and hemostasis).

5.2 Prospect

In the future, supramolecular hydrogels will play a significant role in the market with their unique dynamically non-covalent cross-linking characteristics and various biomedical applications (Fig. 25). However, although a series of excellent properties of supramolecular hydrogel dressings have gradually been recognized by researchers, the use of these materials still has limitations that cannot be ignored in many aspects, such as the cross-linking strategy (the selection conditions of cross-linking interactions and the rationality of various cross-linking interaction combinations), hydrogel network design (relationships between networks and hydrogel properties, complex relationships among multiple networks) and multiple functions (the way of function realization, the mutual interference between various functions). We believe that with the continuous adoption of new preparation methods and the reasonable integration of various strategies, supramolecular hydrogels with more novel functions and better performance will be designed and prepared in the future.

Abbreviation

AAm:	Acrylamide
Ac-CD:	Acryloyl-β-cyclodextrin
ACG:	N-Acryloyl-2-glycine
AD:	Adamantane
ADS:	Andrias davidianus skin secretion
ADxHA:	Adamantane-functionalized hyaluronic acids
AG:	Agarose
ALD-CD:	Monoaldehyde β-CD
ALG:	Alginate
AMPs:	Antimicrobial peptides
ANFs:	Aramid nanofibers
AT:	Aniline tetramer
BetP:	Betamethasone phosphate
bFGF:	Basic fibroblast growth factor
BSA:	Bovine serum albumin
C22:	Alkyl acrylate
CAT:	Catalase
CATNFC:	Cationized nanofibrillated cellulose
CB[6]:	Cucurbit[6]uril
CB[8]:	Cucurbit[8]uril
CCS-PCA:	Catechol-modified carboxymethyl chitosan
β-CD:	β-Cyclodextrin
CDA:	c-di-AMP
CEs:	Casein micelles
CM:	Carmellose
C18M:	Stearyl methacrylate
CMA:	Carboxymethyl agarose
CMCS:	Carboxymethyl chitosan
c-MWCNTs:	Carboxyl-functionalized multi-walled carbon nanotubes
CS:	Chitosan
CTAB:	Cetyltrimethylammonium bromide
CUR:	Curdlan
CY:	Cordycepin
3D:	Three-dimensional
DA:	Dopamine
DAP:	2,6-Diaminopurine
DEX:	Dexamethasone
Dexp:	Dexamethasone sodium phosphate
DMSO:	Dimethyl sulfoxide
DN:	Double network
DNSA:	3,5-Dinitrosalicylic acid
DOX:	Doxycycline
DPCA:	Dihydrophenonthrolin-4-one-3-carboxylic acid
DS:	Diclofenac sodium
DTPA:	Diethylene triamine pentaacetic acid
ECM:	Extracellular matrix
EDA-CD:	Mono-(6-ethylenediamine-6-deoxy)-β-cyclodextrin
EGF:	Epidermal growth factor
2-FA:	2-Amino-2′-fluoro-2′-deoxyadenosine
f-BNNS:	Boron nitrogen nanosheet
FGG-EA:	Tripeptide Phe-Gly-Gly ester derivative
GA:	Gallic acid
GelMA:	Gelatin methacrylate
GO:	Graphene oxide
GT:	Gelatin
GTU:	Ureido-pyrimidinone modified gelatin
GW:	Glycerol–water
HA:	Hyaluronic acid
HBC:	Hydroxybutyl chitosan
HC:	Highly cross-linked
HEC:	Hydroxyethyl cellulose
HS:	Heparin sodium
Hy:	Hymexazol
iGx:	Poly(ionized isocyanoethyl methacrylate-glutamine)
iLEM-GLn:	Fully ionized isocyanoethyl methacrylate-glutamine
LbL:	Layer-by-layer
LDC:	Lidocaine hydrochloride
LMA:	Lauryl methacrylate
MC:	Methylcellulose
MET:	Metformin
MPEG-g-PEAD:	MPEG-grafted poly(ethylene argininylaspartate diglyceride)
MRSA:	Methicillin-resistant Staphylococcus aureus
NIR:	Near infrared
NPs:	Nanoparticles
OA:	Orotic acid
OCDPOSS:	Octa-cyclodextrin polyhedral oligomeric silsesquioxane
PA:	Protocatechualdehyde
PAA:	Poly(acrylic acid)
P(AAm-co-SMA):	Poly(acrylamide-co-stearyl methacrylate)
PAANa:	Poly(sodium acrylate)
PAASP:	Poly-N-acryloyl aspartic acid
PACG:	Poly(N-acryloyl 2-glycine)
PAH:	Polyallylamine
PAM:	Polyacrylamide
PANI:	Polyaniline
PDDA:	Poly(dimethyldiallylamide)
PDGF:	Platelet-derived growth factor
PEG:	Polyethylene glycol
PEGSD:	Poly(glycerol sebacate)-co-poly(ethylene glycol)-g-catechol
PF127-CHO:	Benzaldehyde-terminated Pluronic®F127
PGA:	Polyglycolic acido
PHEAA:	Poly(N-hydroxyethyl acrylamide)
PHMG:	Poly(hexamethylene guanidine)
PL-CAT:	Catechol groups modified ε-polylysine
PMI:	Imidazolidinyl urea reinforced polyurethane
PNCB:	Pinocembrin
PNIPAM:	Poly(N-isopropylacrylamide)
PPP:	Poly(D,L-lactide)–poly(ethylene glycol)–poly(D,L-lactide)
PPVA:	Phytate polyvinyl alcohol
PPy:	Polypyrrole
PSBMA:	Poly 3-[2-(methacryloyloxy)ethyl][(dimethyl)-ammonio]-1-propanesulfonate
PTX:	Paclitaxel
PUD:	Polyurethane diol dispersion
PVA:	Polyvinyl alcohol
PVP:	Polyvinylpyrrolidone
QACs:	Quaternary ammonium compounds
QCS:	Quaternized chitosan
QUE:	Quercetin
RGD:	Tri-peptide Arg-Gly-Asp
rGO:	Reduced graphene oxide
ROS:	Reactive oxygen species
RSF:	Regenerated silk fibroin
SA-DFA:	Deferoxamine grafted alginate
SEM:	Scanning electron microscope
SF:	Silk fibroin
SOD:	Superoxide dismutase
SPU:	Sulfonate-containing polyurethane
TA:	Tannic acid
UPy:	Ureido-pyrimidinone
UV:	Ultraviolet light
VEGF:	Vascular endothelial growth factor

Author contributions

Shaowen Zhuo: investigation, methodology, visualization, writing – original draft, and software. Yongping Liang: writing – review and editing and validation. Zhengying Wu: writing – original draft. Xin Zhao: resources, supervision, writing – review and editing, and validation. Yong Han: resources, supervision, writing – review and editing, and validation. Baolin Guo: resources, supervision, writing – review and editing, and validation.

Conflicts of interest

There are no conflicts to declare.

Acknowledgements

This work was jointly supported by the National Natural Science Foundation of China (grant numbers: 51971171, 52273149, 52003216 and 82272155), the Key Research and Development Program of Shaanxi (2023-YBSF-150), the Project of Supporting Young Talents in Shaanxi University Science and Technology Association (20200404), and the China Postdoctoral Science Foundation (2022M712506).

References

1. S. Enoch and D. J. Leaper, Surgery, 2008, 26, 31–37 Search PubMed.
2. C. L. Baum and C. J. Arpey, Dermatol. Surg., 2005, 31, 674–686 CrossRef CAS.
3. S. Smyth, R. McEver, A. Weyrich, C. Morrell, M. Hoffman, G. Arepally, P. French, H. Dauerman, R. Becker and D. Bhatt, J. Thromb. Haemostasis, 2009, 7, 1759–1766 CrossRef CAS PubMed.
4. Y. Huang, X. Zhao, Z. Zhang, Y. Liang, Z. Yin, B. Chen, L. Bai, Y. Han and B. Guo, Chem. Mater., 2020, 32, 6595–6610 CrossRef CAS.
5. Y. Yang, Y. Liang, J. Chen, X. Duan and B. Guo, Bioact. Mater., 2022, 8, 341–354 CAS.
6. Y. Liang, M. Li, Y. Yang, L. Qiao, H. Xu and B. Guo, ACS Nano, 2022, 16, 3194–3207 CrossRef CAS PubMed.
7. A. Maleki, J. He, S. Bochani, V. Nosrati, M.-A. Shahbazi and B. Guo, ACS Nano, 2021, 15, 18895–18930 CrossRef CAS PubMed.
8. Y. Liang, J. He and B. Guo, ACS Nano, 2021, 15, 12687–12722 CrossRef CAS PubMed.
9. H. Hu and F. J. Xu, Biomater. Sci., 2020, 8, 2084–2101 RSC.
10. J. Zhao, X. Zhao, B. Guo and P. X. Ma, Biomacromolecules, 2014, 15, 3246–3252 CrossRef CAS PubMed.
11. L. Wang, Y. Wu, T. Hu, P. X. Ma and B. Guo, Acta Biomater., 2019, 96, 175–187 CrossRef CAS PubMed.
12. Y. Huang, L. Bai, Y. Yang, Z. Yin and B. Guo, J. Colloid Interface Sci., 2022, 608, 2278–2289 CrossRef CAS PubMed.
13. J. He, Z. Zhang, Y. Yang, F. Ren, J. Li, S. Zhu, F. Ma, R. Wu, Y. Lv, G. He, B. Guo and D. Chu, Nano-Micro Lett., 2021, 13, 1–17 CrossRef.
14. R. Yu, Y. Yang, J. He, M. Li and B. Guo, Chem. Eng. J., 2021, 417, 128278 CrossRef CAS.
15. M. Li, Y. Liang, Y. Liang, G. Pan and B. Guo, Chem. Eng. J., 2022, 427, 132039 CrossRef CAS.
16. X. Zhao, Y. Liang, B. Guo, Z. Yin, D. Zhu and Y. Han, Chem. Eng. J., 2021, 403, 126329 CrossRef CAS.
17. Y. Ren, X. Zhao, X. Liang, P. X. Ma and B. Guo, Int. J. Biol. Macromol., 2017, 105, 1079–1087 CrossRef CAS PubMed.
18. J. Qu, Y. Liang, M. Shi, B. Guo, Y. Gao and Z. Yin, Int. J. Biol. Macromol., 2019, 140, 255–264 CrossRef CAS.
19. R. J. Dong, Y. Pang, Y. Su and X. Y. Zhu, Biomater. Sci., 2015, 3, 937–954 RSC.
20. S. Bernhard and M. W. Tibbitt, Adv. Drug Delivery Rev., 2021, 171, 240–256 CrossRef CAS.
21. T. Kakuta, Y. Takashima, M. Nakahata, M. Otsubo, H. Yamaguchi and A. Harada, Adv. Mater., 2013, 25, 2849–2853 CrossRef CAS PubMed.
22. L. Voorhaar and R. Hoogenboom, Chem. Soc. Rev., 2016, 45, 4013–4031 RSC.
23. J. Skopinska-Wisniewska, S. De la Flor and J. Kozlowska, Int. J. Mol. Sci., 2021, 22, 7402 CrossRef CAS.
24. R. Eelkema and A. Pich, Adv. Mater., 2020, 32, 1906012 CrossRef CAS.
25. B. R. Denzer, R. J. Kulchar, R. B. Huang and J. Patterson, Gels, 2021, 7, 158 CrossRef CAS PubMed.
26. F.-M. Cui, Z.-J. Wu, R. Zhao, Q. Chen, Z.-Y. Liu, Y. Zhao, H.-B. Yan, G.-L. Shen, Y. Tu, D.-H. Zhou, J. Diwu, J. Hou, L. Hu and G.-J. Wang, Macromol. Biosci., 2021, 21, 2000399 CrossRef CAS.
27. J. Xu, H. Wang, L. Jiang, Y. Tao, Y. Song, S. Yu, T. Wang and N. Feng, Macromol. Mater. Eng., 2021, 306, 2100286 CrossRef CAS.
28. G. Xu, Y. Xiao, L. Cheng, R. Zhou, H. Xu, Y. Chai and M. Lang, J. Polym. Sci., Part B: Polym. Phys., 2017, 55, 856–865 CrossRef CAS.
29. Z. Chen, X. Zhang, J. Liang, Y. Ji, Y. Zhou and H. Fang, Int. J. Mol. Sci., 2021, 22, 7610 CrossRef CAS PubMed.
30. H. Yu, Q. Xiao, G. Qi, F. Chen, B. Tu, S. Zhang, Y. Li, Y. Chen, H. Yu and P. Duan, Front. Bioeng. Biotechnol., 2022, 10, 855013 CrossRef PubMed.
31. W. L. Xue, R. Yang, S. Liu, Y. J. Pu, P. H. Wang, W. J. Zhang, X. Y. Tan and B. Chi, Biomater. Sci., 2022, 10, 2417–2427 RSC.
32. D. Zhang, Z. Xu, H. Li, C. Fan, C. Cui, T. Wu, M. Xiao, Y. Yang, J. Yang and W. Liu, Biomater. Sci., 2020, 8, 1455–1463 RSC.
33. Z. Wang, Y. Zhang, Y. Yin, J. Liu, P. Li, Y. Zhao, D. Bai, H. Zhao, X. Han and Q. Chen, Adv. Mater., 2022, 34, 2108300 CrossRef CAS.
34. W.-C. Huang, R. Ying, W. Wang, Y. Guo, Y. He, X. Mo, C. Xue and X. Mao, Adv. Funct. Mater., 2020, 30, 2000644 CrossRef CAS.
35. F. Gao, Y. Zhang, Y. Li, B. Xu, Z. Cao and W. Liu, ACS Appl. Mater. Interfaces, 2016, 8, 8956–8966 CrossRef CAS.
36. Y. Q. Guo, X. L. An and Z. J. Fan, J. Mech. Behav. Biomed. Mater., 2021, 118, 104452 CrossRef CAS PubMed.
37. Y. Li, R. Z. Fu, C. H. Zhu and D. D. Fan, Colloids Surf., B, 2021, 205, 111869 CrossRef CAS PubMed.
38. J. Wang, X. Liu, Y. Wang, M. An and Y. Fan, Int. J. Biol. Macromol., 2022, 211, 678–688 CrossRef CAS.
39. X. Jin, Q. Fu, Z. Gu, Z. Zhang and H. Lv, Int. J. Biol. Macromol., 2021, 184, 787–796 CrossRef CAS.
40. Y. Deng, X. Yang, X. Zhang, H. Cao, L. Mao, M. Yuan and W. Liao, Int. J. Biol. Macromol., 2020, 160, 1242–1251 CrossRef CAS.
41. S. Bi, J. Pang, L. Huang, M. Sun, X. Cheng and X. Chen, Int. J. Biol. Macromol., 2020, 146, 99–109 CrossRef CAS PubMed.
42. Y. Huang, F. Shi, L. Wang, Y. Yang, B. M. Khan, K. L. Cheong and Y. Liu, Int. J. Biol. Macromol., 2019, 132, 729–737 CrossRef CAS.
43. J. Long, A. E. Etxeberria, A. V. Nand, C. R. Bunt, S. Ray and A. Seyfoddin, Mater. Sci. Eng.: C, 2019, 104, 109873 CrossRef CAS.
44. M. Teng, Z. Li, X. Wu, Z. Zhang, Z. Lu, K. Wu and J. Guo, Colloids Surf., B, 2022, 214, 112479 CrossRef CAS PubMed.
45. Y. X. Yang, X. D. Zhao, J. Yu, X. X. Chen, R. Y. Wang, M. Y. Zhang, Q. Zhang, Y. F. Zhang, S. Wang and Y. L. Cheng, Bioact. Mater., 2021, 6, 3962–3975 CAS.
46. F. Gao, Z. Y. Xu, Q. F. Liang, H. F. Li, L. Q. Peng, M. M. Wu, X. L. Zhao, X. Cui, C. S. Ruan and W. G. Liu, Adv. Sci., 2019, 6, 1900867 CrossRef.
47. S. Cao, X. Tong, K. Dai and Q. Xu, J. Mater. Chem. A, 2019, 7, 8204–8209 RSC.
48. H. Deng, Z. Yu, S. Chen, L. Fei, Q. Sha, N. Zhou, Z. Chen and C. Xu, Carbohydr. Polym., 2020, 230, 115565 CrossRef CAS.
49. J. Luo, J. Yang, X. Zheng, X. Ke, Y. Chen, H. Tan and J. Li, Adv. Healthcare Mater., 2020, 9, 1901423 CrossRef CAS.
50. C. Chen, X. Yang, S.-J. Li, C. Zhang, Y.-N. Ma, Y.-X. Ma, P. Gao, S.-Z. Gao and X.-J. Huang, Green Chem., 2021, 23, 1794–1804 RSC.
51. X. Song, Z. Zhang, Z. Shen, J. Zheng, X. Liu, Y. Ni, J. Quan, X. Li, G. Hu and Y. Zhang, ACS Appl. Mater. Interfaces, 2021, 13, 56881–56891 CrossRef CAS.
52. X. Zhao, Y. P. Liang, Y. Huang, J. H. He, Y. Han and B. L. Guo, Adv. Funct. Mater., 2020, 30, 1910748 CrossRef CAS.
53. M. M. Zhang, R. L. Zhang, H. Chen, X. F. Zhang, Y. L. Zhang, H. N. Liu, C. Li, Y. H. Chen, Q. Zeng and G. Z. Huang, ACS Appl. Mater. Interfaces, 2023, 6486–6498,  DOI:10.1021/acsami.2c19997,.
54. C. Xu, L. Cao, C. Cao, H. Chen, H. Zhang, Y. Li and Q. Huang, Chem. Eng. J., 2023, 452, 139195 CrossRef CAS.
55. Y. Y. Yang, G. Y. Feng, J. F. Wang, R. T. Zhang, S. L. Zhong, J. Wang and X. J. Cui, Int. J. Biol. Macromol., 2023, 227, 1038–1047 CrossRef CAS PubMed.
56. C. Y. Qi, Z. X. Dong, Y. K. Huang, J. B. Xu and C. H. Lei, ACS Appl. Mater. Interfaces, 2022, 30385–30397,  DOI:10.1021/acsami.2c06395,.
57. J. Hu, R. Chen, Z. L. Li, F. Z. Wu, Y. H. Yang, Y. Yang, X. K. Li and J. Xiao, Appl. Mater. Today, 2022, 29, 101586 CrossRef.
58. W. J. Yang, R. Zhang, X. Guo, R. X. Ma, Z. Y. Liu, T. Wang and L. H. Wang, J. Mater. Chem. A, 2022, 10, 23649–23665 RSC.
59. M. Criado-Gonzalez, D. Wagner, J. R. Fores, C. Blanck, M. Schmutz, A. Chaumont, M. Rabineau, J. B. Schlenoff, G. Fleith, J. Combet, P. Schaaf, L. Jierry and F. Boulmedais, Chem. Mater., 2020, 32, 1946–1956 CrossRef CAS.
60. X. Hu, L. Yan, Y. Wang and M. Xu, Chem. Eng. J., 2020, 388, 124189 CrossRef CAS.
61. Y. Zhou, H. Li, J. Liu, Y. Xu, Y. Wang, H. Ren and X. Li, Polym. Adv. Technol., 2019, 30, 143–152 CrossRef CAS.
62. Y. Zhu, Q. Luo, H. Zhang, Q. Cai, X. Li, Z. Shen and W. Zhu, Biomater. Sci., 2020, 8, 1394–1404 RSC.
63. K. Ravishankar, M. Venkatesan, R. P. Desingh, A. Mahalingam, B. Sadhasivam, R. Subramaniyam and R. Dhamodharan, Mater. Sci. Eng.: C, 2019, 102, 447–457 CrossRef CAS PubMed.
64. W.-F. Lai, C. Hu, G. Deng, K.-H. Lui, X. Wang, T.-H. Tsoi, S. Wang and W.-T. Wong, Int. J. Pharm., 2019, 566, 101–110 CrossRef CAS.
65. Y. L. Fang, S. S. Huang, X. Gong, J. A. King, Y. Q. Wang, J. C. Zhang, X. Y. Yang, Q. Wang, Y. B. Zhang, G. X. Zhai and L. Ye, Acta Biomater., 2023, 158, 239–251 CrossRef CAS.
66. T. Sangfai, V. Tantishaiyakul, N. Hirun and L. Li, AAPS PharmSciTech, 2017, 18, 605–616 CrossRef CAS PubMed.
67. J. Cheng, D. Amin, J. Latona, E. Heber-Katz and P. B. Messersmith, ACS Nano, 2019, 13, 5493–5501 CrossRef CAS.
68. L. Meng, C. Shao, C. Cui, F. Xu, J. Lei and J. Yang, ACS Appl. Mater. Interfaces, 2020, 12, 1628–1639 CrossRef CAS.
69. Q. F. Yang, P. Wang, C. Z. Zhao, W. Q. Wang, J. F. Yang and Q. Liu, Macromol. Rapid Commun., 2017, 38, 1600741 CrossRef.
70. W. Xu, Q. Song, J.-F. Xu, M. J. Serpe and X. Zhang, ACS Appl. Mater. Interfaces, 2017, 9, 11368–11372 CrossRef CAS.
71. D. Y. Zhu, X. J. Chen, Z. P. Hong, L. Y. Zhang, L. Zhang, J. W. Guo, M. Z. Rong and M. Q. Zhang, ACS Appl. Mater. Interfaces, 2020, 12, 22534–22542 CrossRef CAS.
72. B. Zhang, J. He, M. Shi, Y. Liang and B. Guo, Chem. Eng. J., 2020, 400, 125994 CrossRef CAS.
73. B. H. Yu, A. Y. Zhan, Q. Liu, H. Ye, X. Q. Huang, Y. Shu, Y. Yang and H. Z. Liu, Int. J. Pharm., 2020, 578, 119075 CrossRef CAS.
74. Y. Wu, B. Guo and P. X. Ma, ACS Macro Lett., 2014, 3, 1145–1150 CrossRef CAS PubMed.
75. Z. Li, G. Li, J. Xu, C. Li, S. Han, C. Zhang, P. Wu, Y. Lin, C. Wang, J. Zhang and X. Li, Adv. Mater., 2022, 34, 2109178 CrossRef CAS.
76. X. Song, Z. Zhang, J. Zhu, Y. Wen, F. Zhao, L. Lei, P.-T. Nhan, B. C. Khoo and J. Li, Biomacromolecules, 2020, 21, 1516–1527 CrossRef CAS PubMed.
77. Y. Zhou, Y. Zhang, Z. Dai, F. Jiang, J. Tian and W. Zhang, Biomater. Sci., 2020, 8, 3359–3369 RSC.
78. B. Pourbadiei, S. Y. Adlsadabad, N. Rahbariasr and A. Pourjavadi, Carbohydr. Polym., 2023, 313, 120667 CrossRef CAS PubMed.
79. Y. Rong, R. Liu, P. Jin, C. Liu, X. Wang, L. Fang, L. Chen, W. Wu and C. Yang, J. Mater. Chem. A, 2023, 11, 5895–5901 RSC.
80. S. H. Jeong, S. A. Cheong, T. Y. Kim, H. Choi and S. K. Hahn, ACS Appl. Mater. Interfaces, 2023, 16471–16481,  DOI:10.1021/acsami.3c00191,.
81. X. F. Yang, B. G. Yang, Y. R. Deng, X. Xie, Y. W. Qi, G. Q. Yan, X. Peng, P. C. Zhao and L. M. Bian, Adv. Mater., 2023, 2300636,  DOI:10.1002/adma.202300636.
82. P. Ren, L. Yang, D. Wei, M. Liang, L. Xu, T. Zhang, W. Hu, Z. Zhang and Q. Zhang, Int. J. Biol. Macromol., 2023, 242, 124885 CrossRef CAS.
83. Q. Wang, X.-F. Wang, W.-Q. Sun, R.-L. Lin, M.-F. Ye and J.-X. Liu, ACS Appl. Mater. Interfaces, 2023, 15, 2479–2485 CrossRef CAS PubMed.
84. X. Ke, S. Tang, H. Wang, Y. Cai, Z. Dong, M. Li, J. Yang, X. Xu, J. Luo and J. Li, ACS Appl. Mater. Interfaces, 2022, 14, 53546–53557 CrossRef CAS.
85. L. Shi, Y. Zhao, Q. Xie, C. Fan, J. Hilborn, J. Dai and D. A. Ossipov, Adv. Healthcare Mater., 2018, 7, 1700973 CrossRef PubMed.
86. J. Cao, P. Wu, Q. Cheng, C. He, Y. Chen and J. Zhou, ACS Appl. Mater. Interfaces, 2021, 13, 24095–24105 CrossRef CAS.
87. W. C. Mai, Q. P. Yu, C. P. Han, F. Y. Kang and B. H. Li, Adv. Funct. Mater., 2020, 30, 1909912 CrossRef CAS.
88. Z. L. Li, R. Yu and B. L. Guo, ACS Appl. Bio Mater., 2021, 4, 5926–5943 CrossRef CAS PubMed.
89. L. L. Cai, S. Liu, J. W. Guo and Y. G. Jia, Acta Biomater., 2020, 113, 84–100 CrossRef CAS PubMed.
90. H. J. Zhang, H. S. Xia and Y. Zhao, ACS Macro Lett., 2012, 1, 1233–1236 CrossRef CAS.
91. M. Zhao, Z. Tang, X. Zhang, Z. Li, H. Xiao, M. Zhang, K. Liu, Y. Ni, L. Huang, L. Chen and H. Wu, Compos. Sci. Technol., 2020, 198, 108294 CrossRef CAS.
92. R. Yu, M. Li, Z. Li, G. Pan, Y. Liang and B. Guo, Adv. Healthcare Mater., 2022, 11, 2102749 CrossRef CAS.
93. J. Wang, F. Tang, Y. Wang, Q. P. Lu, S. Q. Liu and L. D. Li, ACS Appl. Mater. Interfaces, 2020, 12, 1558–1566 CrossRef CAS.
94. D. W. Zhao, M. Feng, L. Zhang, B. He, X. Y. Chen and J. Sun, Carbohydr. Polym., 2021, 256, 117580 CrossRef CAS.
95. J. Chen, R. N. Dong, J. Ge, B. L. Guo and P. X. Ma, ACS Appl. Mater. Interfaces, 2015, 7, 28273–28285 CrossRef CAS.
96. Z. X. Deng, Y. Guo, X. Zhao, L. C. Li, R. N. Dong, B. L. Guo and P. X. Ma, Acta Biomater., 2016, 46, 234–244 CrossRef CAS PubMed.
97. C. N. Zhu, T. W. Bai, H. Wang, J. Ling, F. H. Huang, W. Hong, Q. Zheng and Z. L. Wu, Adv. Mater., 2021, 33, 2102023 CrossRef CAS PubMed.
98. J. S. Guo, W. Sun, J. P. Kim, X. L. Lu, Q. Y. Li, M. Lin, O. Mrowczynski, E. B. Rizk, J. G. Cheng, G. Y. Qian and J. Yang, Acta Biomater., 2018, 72, 35–44 CrossRef CAS.
99. J. S. Guo, X. G. Tian, D. H. Xie, K. Rahn, E. Gerhard, M. L. Kuzma, D. F. Zhou, C. Dong, X. C. Bai, Z. H. Lu and J. Yang, Adv. Funct. Mater., 2020, 30, 2002438 CrossRef CAS.
100. K. Bankoti, A. P. Rameshbabu, S. Datta, P. P. Maity, P. Goswami, P. Datta, S. K. Ghosh, A. Mitra and S. Dhara, Mater. Sci. Eng.: C, 2017, 81, 133–143 CrossRef CAS PubMed.
101. J. Zhao, G. X. Luo, J. Wu and H. S. Xia, ACS Appl. Mater. Interfaces, 2013, 5, 2040–2046 CrossRef CAS.
102. R. Shukla, S. K. Kashaw, A. P. Jain and S. Lodhi, Int. J. Biol. Macromol., 2016, 91, 1110–1119 CrossRef CAS.
103. S. Uman, A. Dhand and J. A. Burdick, J. Appl. Polym. Sci., 2020, 137, 48668 CrossRef CAS.
104. L. Zhang, Y. Ma, X. Pan, S. Chen, H. Zhuang and S. Wang, Carbohydr. Polym., 2018, 180, 168–174 CrossRef CAS PubMed.
105. L. Liu, H. C. Shi, H. Yu, R. T. Zhou, J. H. Yin and S. F. Luan, Biomater. Sci., 2019, 7, 5035–5043 RSC.
106. Z. M. Wang, C. Li, J. L. Xu, K. F. Wang, X. Lu, H. P. Zhang, S. X. Qu, G. M. Zhen and F. Z. Ren, Chem. Mater., 2015, 27, 848–856 CrossRef CAS.
107. X. X. Shi, P. Yang, X. F. Peng, C. H. Huang, Q. Y. Qian, B. Wang, J. L. He, X. H. Liu, Y. W. Li and T. R. Kuang, Polymer, 2019, 170, 65–75 CrossRef CAS.
108. X. Q. Zhang, Z. Li, P. Yang, G. G. Duan, X. H. Liu, Z. P. Gu and Y. W. Li, Mater. Horiz., 2021, 8, 145–167 RSC.
109. X. Lin and M. W. Grinstaff, Isr. J. Chem., 2013, 53, 498–510 CrossRef CAS.
110. A. Hildebrandt, D. Miesel and H. Lang, Coord. Chem. Rev., 2018, 371, 56–66 CrossRef CAS.
111. T. Rossow and S. Seiffert, Adv. Polym. Sci., 2015, 268, 1–46 CrossRef CAS.
112. M. Sahin, S. Schlogl, G. Kalinka, J. P. Wang, B. Kaynak, I. Muhlbacher, W. Ziegler, W. Kern and H. Grutzmacher, Polymer, 2018, 141, 221–231 CrossRef CAS.
113. D. C. Tuncaboylu, M. Sahin, A. Argun, W. Oppermann and O. Okay, Macromolecules, 2012, 45, 1991–2000 CrossRef CAS.
114. R. Fredrick, A. Podder, A. Viswanathan and S. Bhuniya, J. Appl. Polym. Sci., 2019, 136, 47665 CrossRef.
115. T. Maeda, Bioengineering, 2019, 6, 107 CrossRef CAS PubMed.
116. J. Qu, X. Zhao, Y. Liang, T. Zhang, P. X. Ma and B. Guo, Biomaterials, 2018, 183, 185–199 CrossRef CAS PubMed.
117. S. Talebian, M. Mehrali, N. Taebnia, C. P. Pennisi, F. B. Kadumudi, J. Foroughi, M. Hasany, M. Nikkhah, M. Akbari, G. Orive and A. Dolatshahi-Pirouz, Adv. Sci., 2019, 6, 1801664 CrossRef.
118. D. L. Zhao, Q. Tang, Q. Zhou, K. Peng, H. Y. Yang and X. Y. Zhang, Soft Matter, 2018, 14, 7420–7428 RSC.
119. J. M. Leferovich, K. Bedelbaeva, S. Samulewicz, X. M. Zhang, D. Zwas, E. B. Lankford and E. Heber-Katz, Proc. Natl. Acad. Sci. U. S. A., 2001, 98, 9830–9835 CrossRef CAS PubMed.
120. M. Mihajlovic, M. Staropoli, M. S. Appavou, H. M. Wyss, W. Pyckhout-Hintzen and R. P. Sijbesma, Macromolecules, 2017, 50, 3333–3346 CrossRef CAS PubMed.
121. Y. Deng, I. Hussain, M. M. Kang, K. W. Li, F. Yao, S. L. Liu and G. D. Fu, Chem. Eng. J., 2018, 353, 900–910 CrossRef CAS.
122. S. M. Mantooth, B. G. Munoz-Robles and M. J. Webber, Macromol. Biosci., 2019, 19, 1800281 CrossRef.
123. G. Sinawang, M. Osaki, Y. Takashima, H. Yamaguchi and A. Harada, Polym. J., 2020, 52, 839–859 CrossRef CAS.
124. J. Szejtli, Chem. Rev., 1998, 98, 1743–1753 CrossRef CAS PubMed.
125. J. Hoque, N. Sangaj and S. Varghese, Macromol. Biosci., 2019, 19, 1800259 CrossRef PubMed.
126. Y. X. Yan, Y. Zhang, Y. Chen and Y. Liu, ACS Appl. Polym. Mater., 2020, 2, 5641–5645 CrossRef CAS.
127. R. Yu, Y. T. Yang, J. H. He, M. Li and B. L. Guo, Chem. Eng. J., 2021, 417, 128278 CrossRef CAS.
128. W. E. Hennink and C. F. van Nostrum, Adv. Drug Delivery Rev., 2012, 64, 223–236 CrossRef.
129. K. Wei, X. Chen, R. Li, Q. Feng and L. Bian, Chem. Mater., 2017, 29, 8604–8610 CrossRef CAS.
130. M. M. Zhang, D. H. Xu, X. Z. Yan, J. Z. Chen, S. Y. Dong, B. Zheng and F. H. Huang, Angew. Chem., Int. Ed., 2012, 51, 7011–7015 CrossRef CAS PubMed.
131. L. Gomez-Tatay and J. M. Hernandez-Andreu, Crit. Rev. Environ. Sci. Technol., 2019, 49, 1587–1621 CrossRef.
132. Y. Yuan, T. Q. Nie, Y. F. Fang, X. R. You, H. Huang and J. Wu, J. Mater. Chem. B, 2022, 10, 2077–2096 RSC.
133. G. H. Fang, X. W. Yang, S. M. Chen, Q. X. Wang, A. W. Zhang and B. Tang, Coord. Chem. Rev., 2022, 454, 214352 CrossRef CAS.
134. L. Y. Shi, P. H. Ding, Y. Z. Wang, Y. Zhang, D. Ossipov and J. Hilborn, Macromol. Rapid Commun., 2019, 40, 1800837 CrossRef.
135. Z. X. Deng, Y. Guo, X. Zhao, P. X. Ma and B. L. Guo, Chem. Mater., 2018, 30, 1729–1742 CrossRef CAS.
136. D. Mozhdehi, S. Ayala, O. R. Cromwell and Z. B. Guan, J. Am. Chem. Soc., 2014, 136, 16128–16131 CrossRef CAS PubMed.
137. S. C. Grindy, R. Learsch, D. Mozhdehi, J. Cheng, D. G. Barrett, Z. B. Guan, P. B. Messersmith and N. Holten-Andersen, Nat. Mater., 2015, 14, 1210–1216 CrossRef CAS.
138. E. Degtyar, M. J. Harrington, Y. Politi and P. Fratzl, Angew. Chem., Int. Ed., 2014, 53, 12026–12044 CrossRef CAS PubMed.
139. H. Chang, C. X. Li, R. L. Huang, R. X. Su, W. Qi and Z. M. He, J. Mater. Chem. B, 2019, 7, 2899–2910 RSC.
140. B. Chen, Y. Liang, L. Bai, M. Xu, J. Zhang, B. Guo and Z. Yin, Chem. Eng. J., 2020, 396, 125335 CrossRef CAS.
141. K. Yan, F. Xu, C. Wang, Y. Li, Y. Chen, X. Li, Z. Lu and D. Wang, Biomater. Sci., 2020, 8, 3193–3201 RSC.
142. X. Wu, H. Sun, Z. Qin, P. Che, X. Yi, Q. Yu, H. Zhang, X. Sun, F. Yao and J. Li, Int. J. Biol. Macromol., 2020, 149, 707–716 CrossRef CAS.
143. S. Zhang, B. Xu, X. Lu, L. Wang, Y. Li, N. Ma, H. Wei, X. Zhang and G. Wang, J. Mater. Chem. C, 2020, 8, 6763–6770 RSC.
144. X. Zhang, Y. H. Tang, P. Y. Wang, Y. Y. Wang, T. T. Wu, T. Li, S. Huang, J. Zhang, H. L. Wang, S. M. Ma, L. L. Wang and W. L. Xu, New J. Chem., 2022, 46, 13838–13855 RSC.
145. L. Shi, P. Ding, Y. Wang, Y. Zhang, D. Ossipov and J. Hilborn, Macromol. Rapid Commun., 2019, 40, 1800837 CrossRef PubMed.
146. H. Geng, P. Zhang, Q. Peng, J. Cui, J. Hao and H. Zeng, Acc. Chem. Res., 2022, 55, 1171–1182 CrossRef CAS PubMed.
147. D. A. Dougherty, Science, 1996, 271, 163–168 CrossRef CAS PubMed.
148. B. Qi, X. Guo, Y. Gao, D. Li, J. Luo, H. Li, S. A. Eghtesadi, C. He, C. Duan and T. Liu, J. Am. Chem. Soc., 2017, 139, 12020–12026 CrossRef CAS PubMed.
149. Z. Ni, H. Yu, L. Wang, X. Liu, D. Shen, X. Chen, J. Liu, N. Wang, Y. Huang and Y. Sheng, Adv. Healthcare Mater., 2022, 11, 2101421 CrossRef CAS PubMed.
150. S. A. Munim and Z. A. Raza, J. Porous Mater., 2019, 26, 881–901 CrossRef CAS.
151. Z. Tang, H. He, L. Zhu, Z. Liu, J. Yang, G. Qin, J. Wu, Y. Tang, D. Zhang, Q. Chen and J. Zheng, Adv. Sci., 2022, 9, 2102557 CrossRef CAS PubMed.
152. J. De Las Rivas and C. Fontanillo, Briefings Funct. Genomics, 2012, 11, 489–496 CrossRef CAS.
153. N. Davari, N. Bakhtiary, M. Khajehmohammadi, S. Sarkari, H. Tolabi, F. Ghorbani and B. Ghalandari, Polymers, 2022, 14, 986 CrossRef CAS.
154. R. Song, J. Zheng, Y. Liu, Y. Tan, Z. Yang, X. Song, S. Yang, R. Fan, Y. Zhang and Y. Wang, Int. J. Biol. Macromol., 2019, 134, 91–99 CrossRef CAS PubMed.
155. Y. Yu, P. Li, C. Zhu, N. Ning, S. Zhang and G. J. Vancso, Adv. Funct. Mater., 2019, 29, 1904402 CrossRef.
156. X. Dong, F. Yao, L. Jiang, L. Liang, H. Sun, S. He, M. Shi, Z. Guo, Q. Yu and M. Yao, J. Mater. Chem. B, 2022, 10, 2215–2229 RSC.
157. M. Shu, S. Long, Y. Huang, D. Li, H. Li and X. Li, Soft Matter, 2019, 15, 7686–7694 RSC.
158. Z. Zhai, K. Xu, L. Mei, C. Wu, J. Liu, Z. Liu, L. Wan and W. Zhong, Soft Matter, 2019, 15, 8603–8610 RSC.
159. X. Ding, J. Gao, H. Awada and Y. Wang, J. Mater. Chem. B, 2016, 4, 1175–1185 RSC.
160. F. Azadikhah and A. R. Karimi, React. Funct. Polym., 2022, 173, 105212 CrossRef CAS.
161. Z. Qin, X. Yu, H. Wu, J. Li, H. Lv and X. Yang, Biomacromolecules, 2019, 20, 3399–3407 CrossRef CAS.
162. J. Chen, R. An, L. Han, X. Wang, Y. Zhang, L. Shi and R. Ran, Mater. Sci. Eng.: C, 2019, 99, 460–467 CrossRef CAS PubMed.
163. X. Deng, B. Huang, Q. Wang, W. Wu, P. Coates, F. Sefat, C. Lu, W. Zhang and X. Zhang, ACS Sustainable Chem. Eng., 2021, 9, 3070–3082 CrossRef CAS.
164. H. Q. Gao, M. C. Chen, Y. Liu, D. D. Zhang, J. J. Shen, N. Ni, Z. M. Tang, Y. H. Ju, X. C. Dai, A. Zhuang, Z. Y. Wang, Q. Chen, X. Q. Fan, Z. Liu and P. Gu, Adv. Mater., 2023, 35, 2204994 CrossRef CAS.
165. J. Zhao, Y.-Y. Peng, J. Wang, D. Diaz-Dussan, W. Tian, W. Duan, L. Kong, X. Hao and R. Narain, Biomacromolecules, 2022, 23, 2552–2561 CrossRef CAS.
166. J. Zhang, L. Chen, B. Shen, Y. Wang, P. Peng, F. Tang and J. Feng, Mater. Sci. Eng.: C, 2020, 117, 111298 CrossRef CAS.
167. S. Tang, J. Yang, L. Lin, K. Peng, Y. Chen, S. Jin and W. Yao, Chem. Eng. J., 2020, 393, 124728 CrossRef CAS.
168. C. Shao, L. Meng, C. Cui and J. Yang, J. Mater. Chem. C, 2019, 7, 15208–15218 RSC.
169. S. Xia, S. Song, F. Jia and G. Gao, J. Mater. Chem. B, 2019, 7, 4638–4648 RSC.
170. R. Xu, S. Ma, P. Lin, B. Yu, F. Zhou and W. Liu, ACS Appl. Mater. Interfaces, 2018, 10, 7593–7601 CrossRef CAS.
171. Z. Jing, Q. Zhang, Y.-Q. Liang, Z. Zhang, P. Hong and Y. Li, Polym. Int., 2019, 68, 1710–1721 CrossRef CAS.
172. J. Pan, Y. Jin, S. Lai, L. Shi, W. Fan and Y. Shen, Chem. Eng. J., 2019, 370, 1228–1238 CrossRef CAS.
173. M. Rodin, J. Li and D. Kuckling, Chem. Soc. Rev., 2021, 50, 8147–8177 RSC.
174. H. W. Zhou, M. Zhang, J. C. Cao, B. Yan, W. Yang, X. L. Jin, A. J. Ma, W. X. Chen, X. B. Ding, G. Zhang and C. Y. Luo, Macromol. Mater. Eng., 2017, 302, 1600352 CrossRef.
175. B. Wu, S. Zhao, X. Yang, L. Zhou, Y. Ma, H. Zhang, W. Li and H. Wang, ACS Nano, 2022, 16, 4126–4138 CrossRef CAS.
176. Y. Wang, X. Fang, S. Li, H. Pan and J. Sun, ACS Appl. Mater. Interfaces, 2021, 15, 25082–25090 CrossRef PubMed.
177. L. Q. Li, P. W. Wu, F. Yu and J. Ma, J. Mater. Chem. A, 2022, 10, 9215–9247 RSC.
178. H. Xin, Gels, 2022, 8, 247 CrossRef CAS PubMed.
179. Y. Tanaka, J. P. Gong and Y. Osada, Prog. Polym. Sci., 2005, 30, 1–9 CrossRef CAS.
180. A. A. Aldana, S. Houben, L. Moroni, M. B. Baker and L. M. Pitet, ACS Biomater. Sci. Eng., 2021, 7, 4077–4101 CrossRef CAS.
181. X. H. Wang, F. Song, D. Qian, Y. D. He, W. C. Nie, X. L. Wang and Y. Z. Wang, Chem. Eng. J., 2018, 349, 588–594 CrossRef CAS.
182. J. P. Gong, Science, 2014, 344, 161–162 CrossRef CAS.
183. R. E. Webber, C. Creton, H. R. Brown and J. P. Gong, Macromolecules, 2007, 40, 2919–2927 CrossRef CAS.
184. H. C. Yu, C. Y. Li, M. Du, Y. H. Song, Z. L. Wu and Q. Zheng, Macromolecules, 2019, 52, 629–638 CrossRef CAS.
185. L. Y. Zhao, Q. F. Zheng, Y. X. Liu, S. Wang, J. Wang and X. F. Liu, Eur. Polym. J., 2020, 124, 109474 CrossRef CAS.
186. S. E. Bakarich, G. C. Pidcock, P. Balding, L. Stevens, P. Calvert and M. I. H. Panhuis, Soft Matter, 2012, 8, 9985–9988 RSC.
187. M. Sabzi, N. Samadi, F. Abbasi, G. R. Mandavinia and M. Babaahmadi, Mater. Sci. Eng.: C, 2017, 74, 374–381 CrossRef CAS PubMed.
188. B. L. Guo, Y. P. Liang and R. A. Dong, Nat. Protoc., 2023, 18, 3322–3354,  DOI:10.1038/s41596-023-00878-9.
189. W. Ha, X. B. Zhao, K. Jiang, Y. Kang, J. Chen, B. J. Li and Y. P. Shi, Chem. Commun., 2016, 52, 14384–14387 RSC.
190. G. C. Qing, X. X. Zhao, N. Q. Gong, J. Chen, X. L. Li, Y. L. Gan, Y. C. Wang, Z. Zhang, Y. X. Zhang, W. S. Guo, Y. Luo and X. J. Liang, Nat. Commun., 2019, 10, 4336 CrossRef PubMed.
191. Q. Chen, H. Chen, L. Zhu and J. Zheng, Macromol. Chem. Phys., 2016, 217, 1022–1036 CrossRef CAS.
192. S. P. Dai, S. Wang, X. Dong, X. Z. Xu, X. T. Cao, Y. W. Chen, X. S. Zhou, J. N. Ding and N. Y. Yuan, J. Mater. Chem. C, 2019, 7, 14581–14587 RSC.
193. J. Y. Sun, X. H. Zhao, W. R. K. Illeperuma, O. Chaudhuri, K. H. Oh, D. J. Mooney, J. J. Vlassak and Z. G. Suo, Nature, 2012, 489, 133–136 CrossRef CAS.
194. Y. Q. Wang, Y. Zhu, J. H. Wang, X. N. Li, X. G. Wu, Y. X. Qin and W. Y. Chen, Compos. Sci. Technol., 2021, 206, 108653 CrossRef CAS.
195. H. Huang, W. Gong, X. Wang, W. He, Y. Hou and J. Hu, Adv. Healthcare Mater., 2022, 2102476 CrossRef CAS PubMed.
196. X.-C. Wang, H.-B. Huang, W. Gong, W.-Y. He, X. Li, Y. Xu, X.-J. Gong and J.-N. Hu, Biomacromolecules, 2022, 23, 1680–1692 CrossRef CAS.
197. F. R. Diniz, R. C. A. Maia, L. R. M. de Andrade, L. N. Andrade, M. Vinicius Chaud, C. F. da Silva, C. B. Corrêa, R. L. C. de Albuquerque Junior, L. Pereira da Costa and S. R. Shin, Nanomaterials, 2020, 10, 390 CrossRef CAS PubMed.
198. Y.-R. Gao, W.-X. Zhang, Y.-N. Wei, Y. Li, T. Fei, Y. Shu and J.-H. Wang, Biomater. Sci., 2022, 10, 1041–1052 RSC.
199. R. Yu, M. Li, Z. Li, G. Pan, Y. Liang and B. Guo, Adv. Healthcare Mater., 2022, 2102749 CrossRef CAS PubMed.
200. R. Yu, Z. Li, G. Pan and B. Guo, Sci. China: Chem., 2022, 65, 2238–2251 CrossRef CAS.
201. F. Song, J. Zhang, J. Lu, Y. Cheng, Y. Tao, C. Shao and H. Wang, Int. J. Biol. Macromol., 2021, 189, 183–193 CrossRef CAS.
202. W. Feng and Z. Wang, Carbohydr. Polym., 2022, 294, 119824 CrossRef CAS.
203. K. Wei, X. Chen, P. Zhao, Q. Feng, B. Yang, R. Li, Z.-Y. Zhang and L. Bian, ACS Appl. Mater. Interfaces, 2019, 11, 16328–16335 CrossRef CAS PubMed.
204. X. Zhang, J. Feng, W. Feng, B. Xu, K. Zhang, G. Ma, Y. Li, M. Yang and F.-J. Xu, ACS Appl. Mater. Interfaces, 2022, 14, 31737–31750 CrossRef CAS PubMed.
205. J. Huang, W. Wang, J. Yu, X. Yu, Q. Zheng, F. Peng, Z. He, W. Zhao, Z. Zhang and X. Li, Colloids Surf., B, 2017, 159, 241–250 CrossRef CAS PubMed.
206. J. Wang, L. Feng, Q. Yu, Y. Chen and Y. Liu, Biomacromolecules, 2021, 22, 534–539 CrossRef CAS PubMed.
207. H. Zhang, K. Liu, Y. Gong, W. Zhu, J. Zhu, F. Pan, Y. Chao, Z. Xiao, Y. Liu, X. Wang, Z. Liu, Y. Yang and Q. Chen, Biomaterials, 2022, 287, 121673 CrossRef CAS.
208. X. Wang, B. Wu, Y. Zhang, X. Dou, C. Zhao and C. Feng, Acta Biomater., 2022, 153, 204–215 CrossRef CAS PubMed.
209. C. Zhang, H. Huang, J. M. Chen, T. T. Zuo, Q. H. Ou, G. F. Ruan, J. He and C. H. Ding, ACS Appl. Mater. Interfaces, 2023, 15, 16369–16379 CrossRef CAS PubMed.
210. J. Xu, K. N. Wang, Y. Y. Li, Y. Li, B. X. Li, H. Q. Luo, H. L. Shi, X. R. Guan, T. Zhang, Y. X. Sun, F. Chen, H. C. He, J. W. Zhang, L. Cai, W. X. Song, J. Wu and X. K. Li, Chem. Eng. J., 2023, 454, 140027 CrossRef CAS.
211. F. Wang, H. Su, Z. Wang, C. F. Anderson, X. Sun, H. Wang, P. Laffont, J. Hanes and H. Cui, ACS Nano, 2023, 17, 10651–10664 CrossRef CAS.
212. S. Chen, Z. Li, C. Zhang, X. Wu, W. Wang, Q. Huang, W. Chen, J. Shi and D. Yuan, Small, 2023, 19, 2301063,  DOI:10.1002/smll.202301063.
213. K. Park, J. I. Dawson, R. O. C. Oreffo, Y.-H. Kim and J. Hong, Biomacromolecules, 2020, 21, 2096–2103 CrossRef CAS.
214. D. Wang, Y. Hu, L. Zhang, H. Cai, Y. Wang and Y. Zhang, Acta Biomater., 2023, 164, 111–123 CrossRef CAS PubMed.
215. Z. Y. Li, L. D. Cao, C. C. Yang, T. N. Liu, H. Zhao, X. B. Luo and Q. M. Chen, ACS Appl. Mater. Interfaces, 2022, 14, 36379–36394 CrossRef CAS.
216. G. M. Fernandes-Cunha, S. H. Jeong, C. M. Logan, P. Le, D. Mundy, F. Chen, K. M. Chen, M. Kim, G.-H. Lee and K.-S. Na, Ocular Surf., 2022, 23, 148–161 CrossRef.
217. Y. Hu, Z. Zhang, Y. Li, X. Ding, D. Li, C. Shen and F. J. Xu, Macromol. Rapid Commun., 2018, 39, 1800069 CrossRef PubMed.
218. W. D. Wu, S. J. Jia, H. L. Xu, Z. H. Gao, Z. Y. Wang, B. T. Lu, Y. X. Ai, Y. J. Liu, R. F. Liu, T. Yang, R. J. Luo, C. P. Hu, L. B. Kong, D. G. Huang, L. Yan, Z. M. Yang, L. Zhu and D. J. Hao, ACS Nano, 2023, 17, 3818–3837 CrossRef CAS PubMed.
219. K. Jian, C. Yang, T. Li, X. Wu, J. Shen, J. Wei, Z. Yang, D. Yuan, M. Zhao and J. Shi, J. Nanobiotechnol., 2022, 20, 201 CrossRef CAS PubMed.
220. S. Bochani, A. Kalantari-Hesari, F. Haghi, V. Alinezhad, H. Bagheri, P. Makvandi, M.-A. Shahbazi, A. Salimi, I. Hirata and V. Mattoli, ACS Appl. Bio Mater., 2022, 5, 4435–4453 CrossRef CAS PubMed.
221. T. Takei, R. Yoshihara, S. Danjo, Y. Fukuhara, C. Evans, R. Tomimatsu, Y. Ohzuno and M. Yoshida, Int. J. Biol. Macromol., 2020, 149, 140–147 CrossRef CAS PubMed.
222. X. Zhao, H. Wu, B. Guo, R. Dong, Y. Qiu and P. X. Ma, Biomaterials, 2017, 122, 34–47 CrossRef CAS.
223. L. P. Qiao, Y. P. Liang, J. Y. Chen, Y. Huang, S. A. Alsareii, A. M. Alamri, F. A. Harraz and B. L. Guo, Bioact. Mater., 2023, 30, 129–141 CAS.
224. Y. Xu, H. Chen, Y. Fang and J. Wu, Adv. Healthcare Mater., 2022, 11, 2200494 CrossRef CAS PubMed.
225. Y. Yu, R. Tian, Y. Zhao, X. Qin, L. Hu, J.-J. Zou, Y.-W. Yang and J. Tian, Adv. Healthcare Mater., 2022, 2201651,  DOI:10.1002/adhm.202201651.
226. J. He, Z. Li, J. Wang, T. Li, J. Chen, X. Duan and B. Guo, Composites, Part B, 2023, 266, 110985 CrossRef CAS.
227. X. Zhao, B. Guo, H. Wu, Y. Liang and P. X. Ma, Nat. Commun., 2018, 9, 2784 CrossRef.
228. A. Sionkowska, B. Kaczmarek, M. Gnatowska and J. Kowalonek, J. Photochem. Photobiol., B, 2015, 148, 333–339 CrossRef CAS.
229. X. Zhao, P. Li, B. Guo and P. X. Ma, Acta Biomater., 2015, 26, 236–248 CrossRef CAS PubMed.
230. B. Jia, G. W. Li, E. R. Cao, J. L. Luo, X. Zhao and H. Y. Huang, Mater. Today Bio, 2023, 19, 100582 CrossRef CAS.
231. H. L. Tan, R. Ma, C. C. Lin, Z. W. Liu and T. T. Tang, Int. J. Mol. Sci., 2013, 14, 1854–1869 CrossRef CAS.
232. K. Y. Zhang, Q. Feng, Z. W. Fang, L. Gu and L. M. Bian, Chem. Rev., 2021, 121, 11149–11193 CrossRef CAS.
233. S. Saini, N. Belgacem, J. Mendes, G. Elegir and J. Bras, ACS Appl. Mater. Interfaces, 2015, 7, 18076–18085 CrossRef CAS PubMed.
234. T. Ikeda, H. Hirayama, H. Yamaguchi, S. Tazuke and M. Watanabe, Antimicrob. Agents Chemother., 1986, 30, 132–136 CrossRef CAS.
235. J. W. He, E. Soderling, P. K. Vallittu and L. V. J. Lassila, J. Biomater. Sci., Polym. Ed., 2013, 24, 565–573 CrossRef CAS PubMed.
236. X. He, Y. F. Ding, W. J. Xie, R. Y. Sun, N. C. Hunt, J. Song, X. X. Sun, C. Peng, Q. H. Zeng, Y. N. Tan and Y. Liu, ACS Biomater. Sci. Eng., 2019, 5, 4726–4738 CrossRef CAS.
237. A. Gopal, V. Kant, A. Gopalakrishnan, S. K. Tandan and D. Kumar, Eur. J. Pharmacol., 2014, 731, 8–19 CrossRef CAS PubMed.
238. H. Qiu, F. Pu, Z. W. Liu, X. M. Liu, K. Dong, C. Q. Liu, J. S. Ren and X. G. Qu, Nano Res., 2020, 13, 496–502 CrossRef CAS.
239. M.-C. Wu, A. R. Deokar, J.-H. Liao, P.-Y. Shih and Y.-C. Ling, ACS Nano, 2013, 7, 1281–1290 CrossRef CAS PubMed.
240. Accounts of Chemical ResearchOcular Surface D. Hu, H. Li, B. Wang, Z. Ye, W. Lei, F. Jia, Q. Jin, K.-F. Ren and J. Ji, ACS Nano, 2017, 11, 9330–9339 CrossRef CAS PubMed.
241. Y. Liang, Z. Li, Y. Huang, R. Yu and B. Guo, ACS Nano, 2021, 15, 7078–7093 CrossRef CAS PubMed.
242. X. He, Z. Li, J. Li, D. Mishra, Y. Ren, I. Gates, J. Hu and Q. Lu, Small, 2021, 17, 2103521 CrossRef CAS.
243. X. Peng, Y. Li, T. Li, Y. Li, Y. Deng, X. Xie, Y. Wang, G. Li and L. Bian, Adv. Sci., 2022, 9, 2203890 CrossRef CAS.
244. L. W. Zhang, M. Liu, Y. J. Zhang and R. J. Pei, Biomacromolecules, 2020, 21, 3966–3983 CrossRef CAS PubMed.
245. X. L. Ma, Q. Bian, J. Y. Hu and J. Q. Gao, J. Controlled Release, 2022, 345, 292–305 CrossRef CAS.
246. J. He, M. Shi, Y. Liang and B. Guo, Chem. Eng. J., 2020, 394, 124888 CrossRef CAS.
247. Y. Liang, X. Zhao, T. Hu, B. Chen, Z. Yin, P. X. Ma and B. Guo, Small, 2019, 15, 1900046 CrossRef.
248. J. W. Yang, R. B. Bai, B. H. Chen and Z. G. Suo, Adv. Funct. Mater., 2020, 30, 1901693 CrossRef CAS.
249. J. Yu, Y. Qin, Y. Yang, X. Zhao, Z. Zhang, Q. Zhang, Y. Su, Y. Zhang and Y. Cheng, Bioact. Mater., 2023, 19, 703–716 CAS.
250. Y. Q. Liang, H. R. Xu, Z. L. Li, A. D. Zhangji and B. L. Guo, Nano-Micro Lett., 2022, 14, 185 CrossRef CAS.
251. B.-L. Guo and Q.-Y. Gao, Carbohydr. Res., 2007, 342, 2416–2422 CrossRef CAS PubMed.
252. R. Dong, X. Zhao, B. Guo and P. X. Ma, ACS Appl. Mater. Interfaces, 2016, 8, 17138–17150 CrossRef CAS PubMed.
253. L. Zhang, L. Wang, B. Guo and P. X. Ma, Carbohydr. Polym., 2014, 103, 110–118 CrossRef CAS PubMed.
254. M. J. Webber and E. T. Pashuck, Adv. Drug Delivery Rev., 2021, 172, 275–295 CrossRef CAS PubMed.
255. P. Liu, W. Lin, R. Wieduwild, R. Towers, A. K. Thomas, M. Guenther, S. Butdayev, M. Wobus, M. Bornhaeuser and Y. Zhang, Chem. Mater., 2021, 33, 2756–2768 CrossRef CAS.
256. Z. Y. Sun, C. J. Song, C. Wang, Y. Q. Hu and J. H. Wu, Mol. Pharm., 2020, 17, 373–391 CAS.
257. L. J. Lei, Y. J. Bai, X. Y. Qin, J. Liu, W. Huang and Q. Z. Lv, Gels, 2022, 8, 301 CrossRef CAS PubMed.
258. N. M. Sangeetha and U. Maitra, Chem. Soc. Rev., 2005, 34, 821–836 RSC.
259. M. R. Saboktakin and R. M. Tabatabaei, Int. J. Biol. Macromol., 2015, 75, 426–436 CrossRef CAS PubMed.
260. Y. Hu, Z. Y. Zhang, Y. Li, X. K. Ding, D. W. Li, C. N. Shen and F. J. Xu, Macromol. Rapid Commun., 2018, 39, 1800069 CrossRef PubMed.
261. C. Laomeephol, M. Guedes, H. Ferreira, R. L. Reis, S. Kanokpanont, S. Damrongsakkul and N. M. Neves, J. Tissue Eng. Regener. Med., 2020, 14, 160–172 CrossRef CAS PubMed.
262. J. He, Y. Liang, M. Shi and B. Guo, Chem. Eng. J., 2020, 385, 123464 CrossRef CAS.
263. M. Li, J. Chen, M. Shi, H. Zhang, P. X. Ma and B. Guo, Chem. Eng. J., 2019, 375, 121999 CrossRef CAS.
264. C. Huang, L. L. Dong, B. H. Zhao, Y. F. Lu, S. R. Huang, Z. Q. Yuan, G. X. Luo, Y. Xu and W. Qian, Clin. Transl. Med., 2022, 12, e1094 CrossRef CAS PubMed.
265. C. Dunnill, T. Patton, J. Brennan, J. Barrett, M. Dryden, J. Cooke, D. Leaper and N. T. Georgopoulos, Int. Wound J., 2017, 14, 89–96 CrossRef PubMed.
266. L. L. Deng, C. Z. Du, P. Y. Song, T. Y. Chen, S. L. Rui, D. G. Armstrong and W. Q. Deng, Oxid. Med. Cell. Longevity, 2021, 2021, 8852759 Search PubMed.
267. W. Q. Zhang, L. Chen, Y. Xiong, A. C. Panayi, A. Abududilibaier, Y. Q. Hu, C. Y. Yu, W. Zhou, Y. Sun, M. F. Liu, H. Xue, L. C. Hu, C. C. Yan, X. D. Xie, Z. Lin, F. Q. Cao, B. B. Mi and G. H. Liu, Front. Bioeng. Biotechnol., 2021, 9, 707479 CrossRef PubMed.
268. U. S. Srinivas, B. W. Q. Tan, B. A. Vellayappan and A. D. Jeyasekharan, Redox Biol., 2019, 25, 101084 CrossRef CAS PubMed.
269. J. Qu, X. Zhao, Y. Liang, Y. Xu, P. X. Ma and B. Guo, Chem. Eng. J., 2019, 362, 548–560 CrossRef CAS.
270. S. Guo, M. Yao, D. Zhang, Y. He, R. Chang, Y. Ren and F. Guan, Adv. Healthcare Mater., 2022, 11, 2101808 CrossRef CAS.
271. M. T. Shi, R. A. Dong, J. Hu and B. L. Guo, Chem. Eng. J., 2023, 457, 141110 CrossRef CAS.
272. L. Wang, T. Li, Z. H. Wang, J. D. Hou, S. T. Liu, Q. Yang, L. Yu, W. H. Guo, Y. J. Wang, B. L. Guo, W. H. Huang and Y. B. Wu, Biomaterials, 2022, 285, 121537 CrossRef CAS PubMed.
273. Z. Wei, E. Volkova, M. R. Blatchley and S. Gerecht, Adv. Drug Delivery Rev., 2019, 149, 95–106 CrossRef.
274. Z. Xing, C. Zhao, S. Wu, C. Zhang, H. Liu and Y. Fan, Biomaterials, 2021, 274, 120872 CrossRef CAS PubMed.
275. R. Chapla and J. L. West, PRGB, 2021, 3, 012002 Search PubMed.
276. H. Stratesteffen, M. Koepf, F. Kreimendahl, A. Blaeser, S. Jockenhoevel and H. Fischer, Biofabrication, 2017, 9, 045002 CrossRef.
277. A. E. Haggerty, I. Maldonado-Lasuncion and M. Oudega, Biomed. Mater., 2018, 13, 044105 CrossRef.
278. Z. Wan, J. He, Y. Yang, T. Chong, J. Wang, B. Guo and L. Xue, Acta Biomater., 2022, 152, 157–170 CrossRef CAS.
279. Z. Li, L. Liu and Y. Chen, Acta Biomater., 2020, 110, 119–128 CrossRef CAS PubMed.
280. C. Cui, T. Wu, X. Chen, Y. Liu, Y. Li, Z. Xu, C. Fan and W. Liu, Adv. Funct. Mater., 2020, 30, 2005689 CrossRef CAS.
281. Y. Yang, X. Liu, Y. Li, Y. Wang, C. Bao, Y. Chen, Q. Lin and L. Zhu, Acta Biomater., 2017, 62, 199–209 CrossRef CAS PubMed.
282. M. P. Diamond, S. D. Wexner, G. S. diZereg, M. Korell, O. Zmora, H. Van Goor and M. Kamar, Surg. Innov., 2010, 17, 183–188 CrossRef PubMed.
283. B. Guo, R. Dong, Y. Bang and M. Li, Nat. Rev. Chem., 2021, 5, 773–791 CrossRef CAS PubMed.
284. Y. T. Yang, Y. Z. Du, J. Zhang, H. L. Zhang and B. L. Guo, Adv. Fiber Mater., 2022, 4, 1027–1057 CrossRef CAS.
285. H. Liu, S. Qin, J. Liu, C. Zhou, Y. Zhu, Y. Yuan, D. A. Fu, Q. Lv, Y. Song, M. Zou, Z. Wang and L. Wang, Adv. Funct. Mater., 2022, 32, 2201108 CrossRef CAS.
286. M. Zhang, P. Lin, X. Song, K. Chen, Y. Yang, Y. Xu, Q. Zhang, Y. Wu, Y. Zhang and Y. Cheng, J. Polym. Sci., 2022, 60, 1511–1520 CrossRef CAS.
287. T. Ito, S. Yamaguchi, D. Soga, T. Yoshimoto and Y. Koyama, Gels, 2022, 8, 462 CrossRef CAS PubMed.
288. S. Yao, Y. Zhao, Y. Xu, B. Jin, M. Wang, C. Yu, Z. Guo, S. Jiang, R. Tang, X. Fang and S. Fan, Adv. Healthcare Mater., 2022, 11, 2200516 CrossRef CAS.
289. Y. Shou, J. Zhang, S. Yan, P. Xia, P. Xu, G. Li, K. Zhang and J. Yin, ACS Biomater. Sci. Eng., 2020, 6, 3619–3629 CrossRef CAS PubMed.
290. X. Wang, Y. Guo, J. Li, M. You, Y. Yu, J. Yang, G. Qin and Q. Chen, ACS Appl. Mater. Interfaces, 2022, 14, 36166–36177 CrossRef CAS PubMed.
291. S. Guo, Y. Ren, R. Chang, Y. He, D. Zhang, F. Guan and M. Yao, ACS Appl. Mater. Interfaces, 2022, 14, 34455–34469 CrossRef CAS PubMed.
292. Y. Liu, Y. Li, H. Shang, W. Zhong, Q. Wang, K. Mequanint, C. Zhu, M. Xing and H. Wei, iScience, 2022, 25, 105106 CrossRef CAS PubMed.
293. Z. Man, L. Sidi, Y. Xubo, Z. Jin and H. Xin, Int. J. Biol. Macromol., 2021, 191, 714–726 CrossRef CAS PubMed.
294. S. Wang, F. Wang, K. Shi, J. Yuan, W. Sun, J. Yang, Y. Chen, D. Zhang and L. Che, Composites, Part B, 2022, 241, 110010 CrossRef CAS.
295. N. K. Preman, S. E. S. Priya, A. Prabhu, S. B. Shaikh, C. Vipin, R. R. Barki, Y. P. Bhandary, P. D. Rekha and R. P. Johnson, J. Mater. Chem. B, 2020, 8, 8585–8598 RSC.
296. Q. Q. Tang, C. W. Chen, Y. G. Jiang, J. J. Huang, Y. Liu, N. M. Peter, G. S. Gu, X. W. Wu, Y. Zhao and J. N. Ren, J. Mater. Chem. B, 2020, 8, 5756–5764 RSC.
297. I. Bano, M. Arshad, T. Yasin, M. A. Ghauri and M. Younus, Int. J. Biol. Macromol., 2017, 102, 380–383 CrossRef CAS PubMed.
298. Z. Ma, G. Bao and J. Li, Adv. Mater., 2021, 33, 2007663 CrossRef CAS PubMed.
299. S. Jin, S. Kim, D. S. Kim, D. Son and M. Shin, Adv. Funct. Mater., 2022, 32, 2110320 CrossRef CAS.
300. T. L. Landsman, T. Touchet, S. M. Hasan, C. Smith, B. Russell, J. Rivera, D. J. Maitland and E. Cosgriff-Hernandez, Acta Biomater., 2017, 47, 91–99 CrossRef CAS PubMed.
301. Y.-F. Zhao, J.-Y. Zhao, W.-Z. Hu, K. Ma, Y. Chao, P.-J. Sun, X.-B. Fu and H. Zhang, J. Mater. Chem. B, 2019, 7, 1855–1866 RSC.
302. F. I. Broekema, W. van Oeveren, A. Boerendonk, P. K. Sharma and R. R. M. Bos, Bio-Med. Mater. Eng., 2016, 27, 149–159 CAS.
303. X. Chen, C. Cui, Y. Liu, C. Fan, M. Xiao, D. Zhang, Z. Xu, Y. Li, J. Yang and W. Liu, Biomater. Sci., 2020, 8, 3760–3771 RSC.
304. M. Zhang, J. Yu, K. Shen, R. Wang, J. Du, X. Zhao, Y. Yang, K. Xu, Q. Zhang, Y. Zhang and Y. Cheng, Chem. Mater., 2021, 33, 6453–6463 CrossRef CAS.
305. S. R. Van Tomme, G. Storm and W. E. Hennink, Int. J. Pharm., 2008, 355, 1–18 CrossRef CAS PubMed.
306. Z. Y. Wan, J. H. He, Y. T. Yang, T. Chong, J. X. Wang, B. L. Guo and L. Xue, Acta Biomater., 2022, 152, 157–170 CrossRef CAS PubMed.
307. M. Zawani and M. B. Fauzi, Biomedicines, 2021, 9, 527 CrossRef CAS PubMed.
308. H. D. N. Tran, K. D. Park, Y. C. Ching, C. Huynh and D. H. Nguyen, J. Ind. Eng. Chem., 2020, 89, 58–82 CrossRef CAS.
309. Z. Sheikh, P. J. Brooks, O. Barzilay, N. Fine and M. Glogauer, Materials, 2015, 8, 5671–5701 CrossRef CAS PubMed.
310. M. D. Konieczynska, J. C. Villa-Camacho, C. Ghobril, M. Perez-Viloria, K. M. Tevis, W. A. Blessing, A. Nazarian, E. K. Rodriguez and M. W. Grinstaff, Angew. Chem., Int. Ed., 2016, 55, 9984–9987 CrossRef CAS PubMed.
311. M. Grosjean, L. Gangolphe and B. Nottelet, Adv. Funct. Mater., 2023, 33, 2205315 CrossRef CAS.
312. M. Li, G. Pan, Y. Yang and B. Guo, Nano Today, 2023, 48, 101720 CrossRef CAS.
313. R. Dong, H. Zhang and B. Guo, Natl. Sci. Rev., 2022, 9, nwac162 CrossRef CAS PubMed.
314. D. Liu, H. Zhou, Y. Zhao, C. Huyan, Z. Wang, H. Torun, Z. Guo, S. Dai, B. B. Xu and F. Chen, Small, 2022, 18, 2203258 CrossRef CAS PubMed.
315. B. Guo, L. Glavas and A.-C. Albertsson, Prog. Polym. Sci., 2013, 38, 1263–1286 CrossRef CAS.
316. Z. Deng, Y. Guo, X. Zhao, P. X. Ma and B. Guo, Chem. Mater., 2018, 30, 1729–1742 CrossRef CAS.
317. Y. P. Liang, L. P. Qiao, B. W. Qiao and B. L. Guo, Chem. Sci., 2023, 14, 3091–3116 RSC.
318. Z. Deng, T. Hu, Q. Lei, J. He, P. X. Ma and B. Guo, ACS Appl. Mater. Interfaces, 2019, 11, 6796–6808 CrossRef CAS PubMed.
319. Y. Liang, X. Zhao, P. X. Ma, B. Guo, Y. Du and X. Han, J. Colloid Interface Sci., 2019, 536, 224–234 CrossRef CAS PubMed.
320. J. Qu, X. Zhao, P. X. Ma and B. Guo, Acta Biomater., 2017, 58, 168–180 CrossRef CAS PubMed.
321. Y. T. Yang, M. Li, G. Y. Pan, J. Y. Chen and B. L. Guo, Adv. Funct. Mater., 2023, 33, 2214089 CrossRef CAS.
322. R. Dong and B. Guo, Nano Today, 2021, 41, 101290 CrossRef CAS.
323. B. Guo and P. X. Ma, Biomacromolecules, 2018, 19, 1764–1782 CrossRef CAS PubMed.
324. R. Dong, P. X. Ma and B. Guo, Biomaterials, 2020, 229, 119584 CrossRef CAS PubMed.

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