Preparation and characterization of a dual cross-linking injectable hydrogel based on sodium alginate and chitosan quaternary ammonium salt

Effect of sodium alginate block type on the physicochemical properties and curcumin release behavior of quaternized chitosan-oxidized sodium alginate Schiff base hydrogels

Controlling bioactive ingredients release by modulating the 3D network structure of cross-linked hydrogels is important for functional food development. Hereby, oxidized sodium alginate (OSA) with varying aldehyde contents was formed by periodate oxidation of sodium alginate (SA) with different β-d-mannuronic acid (M) and α-l-guluronic acid (G) ratios (M/G = 1:2, 1:1, and 2:1) and its structure was characterized. Moreover, hydrogels were prepared via Schiff base and electrostatic interactions between quaternized chitosan (QCS) and OSA. The properties of hydrogels such as microstructure, thermal stability, swelling and controlled release were investigated. The results showed that OSA with M/G = 1:2 had the highest content of aldehyde groups, and the hydrogel formed by it and QCS had higher thermal stability and a denser network structure with the lowest equilibrium swelling rate, which could better control the release of curcumin. Additionally, it had good self-healing and can recover rapidly after the rupture of its network structure.

Fabrication and characterization of physically crosslinked alginate/chitosan-based hydrogel loaded with neomycin for the treatment of skin infections caused by Staphylococcus aureus

Staphylococcus aureus is a pathogen widely involved in wound infection due to its ability to release several virulence factors that impair the skin healing process, as well as its mechanism of drug resistance. Herein, sodium alginate and chitosan were combined to produce a hydrogel for topical delivery of neomycin to combat S. aureus associated with skin complications. The hydrogel was formulated by combining sodium alginate (50 mg/mL) and chitosan (50 mg/mL) solutions in a ratio of 9:1 (HBase). Neomycin was added to HBase to achieve a concentration of 0.4 mg/mL (HNeo). The incorporation of neomycin into the product was confirmed by scanning electron microscopy, FTIR and TGA analysis. The hydrogels produced are homogeneous, have a high swelling capacity, and show biocompatibility using erythrocytes and fibroblasts as models. The formulations showed physicochemical and pharmacological stability for 60 days at 4 ± 2 °C. HNeo totally inhibited the growth of S. aureus after 4 h. The antimicrobial effects were confirmed using ex vivo (porcine skin) and in vivo (murine) wound infection models. Furthermore, the HNeo-treated mice showed lower severity scores than those treated with HBase. Taken together, the obtained results present a new low-cost bioproduct with promising applications in treating infected wounds.

Advances in enhancing the mechanical properties of biopolymer hydrogels via multi-strategic approaches

The limited mechanical properties of biopolymer-based hydrogels have hindered their widespread applications in biomedicine and tissue engineering. In recent years, researchers have shown significant interest in developing novel approaches to enhance the mechanical performance of hydrogels. This review focuses on key strategies for enhancing mechanical properties of hydrogels, including dual-crosslinking, double networks, and nanocomposite hydrogels, with a comprehensive analysis of their underlying mechanisms, benefits, and limitations. It also introduces the classic application scenarios of biopolymer-based hydrogels and the direction of future research efforts, including wound dressings and tissue engineering based on 3D bioprinting. This review is expected to deepen the understanding of the structure-mechanical performance-function relationship of hydrogels and guide the further study of their biomedical applications.

Multifunctional polysaccharide/metal/polyphenol double-crosslinked hydrogel for infected wound

Bacterial-infected wounds present a significant challenge in the medical field, posing a severe threat to public health. Traditional wound dressings have limited efficacy in treating bacterial-infected wounds, and antibiotics suffer from cytotoxicity and drug resistance. Consequently, an urgent requirement exists for developing multifunctional wound dressings capable of providing superior antimicrobial activity and expediting wound repair. In recent years, chitosan-based natural polysaccharide hydrogels have garnered attention for their biocompatibility, antimicrobial properties, and ability to aid in hemostasis. This study presents the development of a multi-functional, bi-dynamic network hydrogel for the treatment of wounds infected with bacteria. The hydrogel consists of a backbone of chitosan grafted with chlorogenic acid (CA-ECS), oxidized pullulan polysaccharides (OP), and zinc ions (Zn2+). The CA-ECS/OP/Zn2+ hydrogel displayed strong adhesion, good injectability, and high mechanical strength and was biodegradable and biocompatible. Furthermore, adding Zn2+ and CA enhanced the hydrogel's mechanical properties and antioxidant and antimicrobial activities. In a rat model of full-thickness skin wounds infected with S. aureus, the CA-ECS/OP/Zn2+ hydrogel demonstrated great anti-inflammatory, angiogenic, and folliculogenic properties, resulting in accelerated wound healing. The CA-ECS/OP/Zn2+ hydrogel has great potential for treating bacterial-infected wounds.

Collagen fibril-like injectable hydrogels from self-assembled nanoparticles for promoting wound healing

Soft hydrogels are excellent candidate materials for repairing various tissue defects, yet the mechanical strength, anti-swelling properties, and biocompatibility of many soft hydrogels need to be improved. Herein, inspired by the nanostructure of collagen fibrils, we developed a strategy toward achieving a soft but tough, anti-swelling nanofibrillar hydrogel by combining the self-assembly and chemical crosslinking of nanoparticles. Specifically, the collagen fibril-like injectable hydrogel was subtly designed and fabricated by self-assembling methylacrylyl hydroxypropyl chitosan (HM) with laponite (LAP) to form nanoparticles, followed by the inter-nanoparticle bonding through photo-crosslinking. The assembly mechanism of nanoparticles was elucidated by both experimental and simulation techniques. Due to the unique structure of the crosslinked nanoparticles, the nanocomposite hydrogels exhibited low stiffness (G'< 2 kPa), high compressive strength (709 kPa), and anti-swelling (swelling ratio of 1.07 in PBS) properties. Additionally, by harnessing the photo-crosslinking ability of the nanoparticles, the nanocomposite hydrogels were processed as microgels, which can be three-dimensionally (3D) printed into complex shapes. Furthermore, we demonstrated that these nanocomposite hydrogels are highly biocompatible, biodegradability, and can effectively promote fibroblast migration and accelerate blood vessel formation during wound healing. This work presents a promising approach to develop biomimetic, nanofibrillar soft hydrogels for regenerative medicine applications.

A chitosan derivative/phytic acid polyelectrolyte complex endowing polyvinyl alcohol film with high barrier, flame-retardant, and antibacterial effects

Films with high barrier, flame-retardant, and antibacterial properties are beneficial in terms of food and logistics safety. Herein, a polyelectrolyte complex (PEC) of N-(2-hydroxyl)-propyl-3-trimethylammonium chitosan chloride (HTCC, chitosan derivative) and phytic acid (PA) was successfully prepared and then incorporated into a polyvinyl alcohol (PVA) matrix to fabricate a composite film with satisfactory barrier, fire-retardant, and antibacterial properties. The influence of HTCC/PA (HTPA) on the structural, physical and functional properties of the PVA matrix was investigated. Compared with the PVA film, PVA-HTPA6 film exhibited 3.38 times of flexibility and 83.33 % and 80.64 % of water vapor permeability and oxygen permeability, respectively. Benefiting from HTPA, the PVA-HTPA6 film exhibited outstanding flame-retardant capacity, with a high LOI value (33.30 %) and immediate self-extinguishing behaviour. Furthermore, the HTPA endowed the films with excellent antibacterial properties. Compared with other films, the PVA-HTPA6 film effectively maintained the quality of pork during storage at 4 °C for 9 days. Our findings indicate that the films are promising for packaging and logistics safety with oil-containing foods.

Poly(ethylene glycol) Methyl Ether Acrylate-Grafted Chitosan-Based Micro- and Nanoparticles as a Drug Delivery System for Antibiotics

Nanotechnology is the science of creating materials at the nanoscale by using various devices, structures, and systems that are often inspired by nature. Micro- and nanoparticles (MPs, NPs) are examples of such materials that have unique properties and can be used as carriers for delivering drugs for different biomedical applications. Chitosan (CS) is a natural polysaccharide that has been widely studied, but it has a problem with low water solubility at neutral or basic pH, which limits its processability. The goal of this work was to use a chemically modified CS with poly(ethylene glycol) methyl ether acrylate (PEGA) to prepare CS micronic and submicronic particles (MPs/NPs) that can deliver different types of antibiotics, respectively, levofloxacin (LEV) and Ciprofloxacin (CIP). The particle preparation procedure employed a double crosslinking method, ionic followed by a covalent, in a water/oil emulsion. The studied process parameters were the precursor concentration, stirring speeds, and amount of ionic crosslinking agent. MPs/NPs were characterized by FT-IR, SEM, light scattering granulometry, and Zeta potential. MPs/NPs were also tested for their water uptake capacity in acidic and neutral pH conditions, and the results showed that they had a pH-dependent behavior. The MPs/NPs were then used to encapsulate two separate drugs, LEV and CIP, and they showed excellent drug loading and release capacity. The MPs/NPs were also found to be safe for cells and blood, which demonstrated their potential as suitable drug delivery systems for biomedical applications.

Quaternary-ammonium chitosan, a promising packaging material in the food industry

Quaternary-ammonium chitosan (QAC) is a polysaccharide with good water solubility, bacteriostasis, and biocompatibility. QAC is obtained by methylating or grafting the quaternary-ammonium group of chitosan and is an important compound in the food industry. Various QAC-based complexes have been prepared using reversible intermolecular interactions, such as electrostatic interactions, hydrogen bonding, metal coordination, host-guest interactions, and covalent bonding interactions consisting of Schiff base bonding and dynamic chemical bond cross-linking. In the food industry, QAC is often used as a substrate in film or coating for food preservation and as a carrier for active substances to improve the encapsulation efficiency and storage stability of functional food ingredients. In this review, we have assimilated the latest information on QAC to facilitate further discussions and future research. Advancement in research on QAC would contribute toward technology acceleration and its increased contribution to the field of food technology.

Fabrication and characterization of microwave-assisted synthesis of carbon dots crosslinked sodium alginate hydrogel films

In this study, potassium-incorporated carbon dots (K-CDs) and nitrogen-incorporated carbon dots (N-CDs) were composted using the microwave-assisted method, in which the carbon source is citric acid. Subsequently, the prepared CDs were added into sodium alginate (NaAlg)/CaCO3 to form a hydrogel film. The Ca2+ in the system is tend to be released in the presence of acidic CDs to promote the cross-linking of NaAlg. This study presents a NaAlg hydrogel film preparation process that requires no additional acid and is natural and environmentally friendly. Moreover, it gives the NaAlg hydrogel film excellent antioxidant and antimicrobial properties and also improves its mechanical properties and gel strength. The release behaviors of the CDs in the hydrogel films were also explored. The prepared CD-incorporated NaAlg hydrogel films have potential applications in medical, biological engineering, food preservation, and other fields owing to their functional properties.

Characterization of structural and functional properties of soy protein isolate and sodium alginate interpenetrating polymer network hydrogels

BACKGROUND

This study used enzymatic and Ca2+ cross-linking methods to prepare edible soy protein isolate (SPI) and sodium alginate (SA) interpenetrating polymer network hydrogels to overcome the disadvantages of traditional interpenetrating polymer network (IPN) hydrogels, such as poor performance, high toxicity, and inedibility. The influence of changes in SPI and SA mass ratio on the performance of SPI-SA IPN hydrogels was investigated.

RESULTS

Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure of the hydrogels. Texture profile analysis (TPA), rheological properties, swelling rate, and Cell Counting Kit-8 (CCK-8) were used to evaluate physical and chemical properties and safety. The results showed that, compared with SPI hydrogel, IPN hydrogels had better gel properties and structural stability. As the mass ratio of SPI-SA IPN changed from 1:0.2 to 1:1, the gel network structure of hydrogels also tended to be dense and uniform. The water retention and mechanical properties of these hydrogels, such as storage modulus (G'), loss modulus (G"), and gel hardness increased significantly and were greater than those of the SPI hydrogel. Cytotoxicity tests were also performed. The biocompatibility of these hydrogels was good.

CONCLUSIONS

This study proposes a new method to prepare food-grade IPN hydrogels with mechanical properties of SPI and SA, which may have strong potential for the development of new foods. © 2023 Society of Chemical Industry.

Double Network Physical Crosslinked Hydrogel for Healing Skin Wounds: New Formulation Based on Polysaccharides and Zn2

Developing convenient, efficient, and natural wound dressings remain the foremost strategy for treating skin wounds. Thus, we innovatively combined the semi-dissolved acidified sol-gel conversion method with the internal gelation method to fabricate SA (sodium alginate)/CS (chitosan)/Zn2+ physically cross-linked double network hydrogel and named it SA/CS/Zn2+ PDH. The characterization results demonstrated that increased Zn2+ content led to hydrogels with improved physical and chemical properties, such as rheology, water retention, and swelling capacity. Moreover, the hydrogels exhibited favorable antibacterial properties and biocompatibility. Notably, the establishment of an in vitro pro-healing wound model further confirmed that the hydrogel had a superior ability to repair wounds and promote skin regeneration. In future, as a natural biomaterial with antimicrobial properties, it has the potential to promote wound healing.

Preparation and Properties of Self-Cross-Linking Hydrogels Based on Chitosan Derivatives and Oxidized Sodium Alginate

A self-cross-linking and biocompatible hydrogel has wide application potential in the field of tissue engineering. In this work, an easily available, biodegradable, and resilient hydrogel was prepared using a self-cross-linking method. This hydrogel was composed of N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC) and oxidized sodium alginate (OSA). A stable and reversible cross-linking network was formed by the Schiff base self-cross-linked and hydrogen bonding. The addition of a shielding agent (NaCl) may weaken the intense electrostatic effect between HACC and OSA and solve the problem of flocculation caused by the rapid formation of ionic bonds, which provided an extended time for the Schiff base self-cross-linked reaction for forming a homogeneous hydrogel. Interestingly, the shortest time for the formation of the HACC/OSA hydrogel was within 74 s and the hydrogel had a uniform porous structure and enhanced mechanical properties. The HACC/OSA hydrogel withstood large compression deformation due to improved elasticity. What's more, this hydrogel possessed favorable swelling property, biodegradation, and water retention. The HACC/OSA hydrogels have great antibacterial properties against Staphylococcus aureus and Escherichia coli and demonstrated good cytocompatibility as well. The HACC/OSA hydrogels have a good sustained release effect on rhodamine (model drug). Thus, the obtained self-cross-linked HACC/OSA hydrogels in this study have potential applications in the field of biomedical carriers.

Visual Colorimetric Detection of Edible Oil Freshness for Peroxides Based on Nanocellulose

Traditional methods for evaluating the edibility of lipids involve the use of organic reagents and complex operations, which limit their routine use. In this study, nanocellulose was prepared from bamboo, and a colorimetric reading strategy based on nanocellulose composite hydrogels was explored to monitor the freshness of edible oils. The hydrogels acted as carriers for peroxide dyes that changed color according to the freshness of the oil, and color information was digitized using UV-vis and RGB analysis. The sensitivity and accuracy of the hydrogel were verified using H₂O₂, which showed a linear relationship between absorbance and H₂O₂ content in the range of 0-0.5 and 0.5-11 mmol/kg with R² of 0.9769 and 0.9899, respectively, while the chromatic parameter showed an exponential relationship with R² of 0.9626. Surprisingly, the freshness of all seven edible oil samples was correctly identified by the hydrogel, with linear correlation coefficients greater than 0.95 in the UV-vis method and exponential correlation coefficients greater than 0.92 in the RGB method. Additionally, a peroxide value color card was established, with an accuracy rate of 91.67%. This functional hydrogel is expected to be used as a household-type oil freshness indicator to meet the needs of general consumers.

Diversity of Bioinspired Hydrogels: From Structure to Applications

Hydrogels are three-dimensional networks with a variety of structures and functions that have a remarkable ability to absorb huge amounts of water or biological fluids. They can incorporate active compounds and release them in a controlled manner. Hydrogels can also be designed to be sensitive to external stimuli: temperature, pH, ionic strength, electrical or magnetic stimuli, specific molecules, etc. Alternative methods for the development of various hydrogels have been outlined in the literature over time. Some hydrogels are toxic and therefore are avoided when obtaining biomaterials, pharmaceuticals, or therapeutic products. Nature is a permanent source of inspiration for new structures and new functionalities of more and more competitive materials. Natural compounds present a series of physico-chemical and biological characteristics suitable for biomaterials, such as biocompatibility, antimicrobial properties, biodegradability, and nontoxicity. Thus, they can generate microenvironments comparable to the intracellular or extracellular matrices in the human body. This paper discusses the main advantages of the presence of biomolecules (polysaccharides, proteins, and polypeptides) in hydrogels. Structural aspects induced by natural compounds and their specific properties are emphasized. The most suitable applications will be highlighted, including drug delivery, self-healing materials for regenerative medicine, cell culture, wound dressings, 3D bioprinting, foods, etc.

The Development of a Polysaccharide-Based Hydrogel Encapsulating Tobramycin-Loaded Gelatine Microspheres as an Antibacterial System

Bacterial infection contributes to the bioburden of wounds, which is an essential factor in determining whether a wound can heal. Wound dressings with antibacterial properties that can promote wound-healing are highly desired for the treatment of chronic wound infections. Herein, we fabricated a simple polysaccharide-based hydrogel dressing encapsulating tobramycin-loaded gelatine microspheres with good antibacterial activity and biocompatibility. We first synthesised long-chain quaternary ammonium salts (QAS) by the reaction of tertiary amines with epichlorohydrin. The amino groups of carboxymethyl chitosan were then conjugated with QAS through the ring-opening reaction and QAS-modified chitosan (CMCS) was obtained. The antibacterial analysis showed that both QAS and CMCS could kill E. coli and S. aureus at relatively low concentrations. QAS with 16 carbon atoms has a MIC of 16 μg/mL for E. coli and 2 μg/mL for S. aureus. A series of formulations of tobramycin-loaded gelatine microspheres (TOB-G) were generated and the best formulation was selected by comparing the characters of the microspheres. The microsphere fabricated by 0.1 mL GTA was selected as the optimal candidate. We then used CMCS, TOB-G, and sodium alginate (SA) to prepare physically crosslinking hydrogels using CaCl2 and investigated the mechanical properties, antibacterial activity, and biocompatibility of the hydrogels. In summary, the hydrogel dressing we produced can be used as an ideal alternative for the management of bacteria-infected wounds.

Release of Bioactive Molecules from Graphene Oxide-Alginate Hybrid Hydrogels: Effect of Crosslinking Method

To investigate the influence of crosslinking methods on the releasing performance of hybrid hydrogels, we synthesized two systems consisting of Graphene oxide (GO) as a functional element and alginate as polymer counterpart by means of ionic gelation (physical method, HA−GOP) and radical polymerization (chemical method, HA−GOC). Formulations were optimized to maximize the GO content (2.0 and 1.15% for HA−GOP and HA−GOC, respectively) and Curcumin (CUR) was loaded as a model drug at 2.5, 5.0, and 7.5% (by weight). The physico-chemical characterization confirmed the homogeneous incorporation of GO within the polymer network and the enhanced thermal stability of hybrid vs. blank hydrogels. The determination of swelling profiles showed a higher swelling degree for HA−GOC and a marked pH responsivity due to the COOH functionalities. Moreover, the application of external voltages modified the water affinity of HA−GOC, while they accelerated the degradation of HA−GOP due to the disruption of the crosslinking points and the partial dissolution of alginate. The evaluation of release profiles, extensively analysed by the application of semi-empirical mathematical models, showed a sustained release from hybrid hydrogels, and the possibility to modulate the releasing amount and rate by electro-stimulation of HA−GOC.

Regeneration Approach to Enhance the Antimicrobial and Antioxidant Activities of Chitosan for Biomedical Applications

Owing to its biodegradability, non-toxicity, and biocompatibility, chitosan (Cs) is a ubiquitous biopolymer. However, applications of Cs are limited owing to the existence of strong inter- and intra-molecular hydrogen bonds within its network. To address this issue, we regenerated medium-molecular-weight Cs to enhance the physico-chemical and functional properties using a cationic approach. Accordingly, alkaline modification was employed to introduce an additional positive charge to the amine functional groups of Cs and moderately disintegrate the inter- and intra-hydrogen bonds. The chemical structure of Cs and regenerated chitosan (RCs) was confirmed through Fourier transform infrared and ¹H-NMR spectroscopy. RCs showed higher zeta potential value compared to Cs. Additionally, using X-ray diffraction, RCs exhibited low crystallinity, which can be attributed to the repulsive force caused by the positive surface charge and the destruction of hydrogen bonds. The RCs exhibited stronger antioxidant activity than Cs. Furthermore, the minimum inhibition concentrations (MICs) of RCs against Escherichia coli and Staphylococcus aureus were reduced by almost four times compared with those of Cs. The superior functional properties of RCs can be attributed to the formation of a polycationic structure after alkaline modification. Thus, RCs can be introduced as potent agents for various biomedical purposes.

Polysaccharides-Based Injectable Hydrogels: Preparation, Characteristics, and Biomedical Applications

Polysaccharides-based injectable hydrogels are a unique group of biodegradable and biocompatible materials that have shown great potential in the different biomedical fields. The biomolecules or cells can be simply blended with the hydrogel precursors with a high loading capacity by homogenous mixing. The different physical and chemical crosslinking approaches for preparing polysaccharide-based injectable hydrogels are reviewed. Additionally, the review highlights the recent work using polysaccharides-based injectable hydrogels as stimuli-responsive delivery vehicles for the controlled release of different therapeutic agents and viscoelastic matrix for cell encapsulation. Moreover, the application of polysaccharides-based injectable hydrogel in regenerative medicine as tissue scaffold and wound healing dressing is covered.

Preparation and properties of nano silica-based bioactive glass/apatite/sodium alginate composite hydrogel

In this paper, given the lack of osteogenic activity of sodium alginate (SA) hydrogel and to simulate the composition of natural bone, ionic-crosslinking NBG/n-HA/SA hydrogel scaffolds were prepared by using nano bioactive glass (NBG) and nano hydroxyapatite (n-HA) with high bioactivity as composite calcium sources and reinforcement phases, and D-gluconic acid δ-lactone (GDL) as the coagulant. The results showed that the mixture of the precursor forming the network had good injectability and plasticity. When the dosage of GDL was 0.75 g, the gelling time of the composite hydrogel could be regulated within 4-8 min, and the hydrogel had high compressive strength (170-220 kPa), as well. When the mass ratio of calcium source to SA was 1:1, the crosslinking network was relatively uniform with a considerable number of large pores around 40 μm in the structure. In the immersion experiment in vitro, it was found that the composite hydrogel could promote the deposition of bone-like apatite on the material's surface. Meanwhile, the cell experiments in vitro verified that the NBG/n-HA/SA composite hydrogel had good cytocompatibility without cytotoxicity. Moreover, the composite hydrogel could enhance the activity of ALP of mouse bone marrow mesenchymal stem cells, and thus, it had good osteogenic activity.

Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities

Hydrogels, as interconnected networks (polymer mesh; physically, chemically, or dynamic crosslinked networks) incorporating a high amount of water, present structural characteristics similar to soft natural tissue. They enable the diffusion of different molecules (ions, drugs, and grow factors) and have the ability to take over the action of external factors. Their nature provides a wide variety of raw materials and inspiration for functional soft matter obtained by complex mechanisms and hierarchical self-assembly. Over the last decade, many studies focused on developing innovative and high-performance materials, with new or improved functions, by mimicking biological structures at different length scales. Hydrogels with natural or synthetic origin can be engineered as bulk materials, micro- or nanoparticles, patches, membranes, supramolecular pathways, bio-inks, etc. The specific features of hydrogels make them suitable for a wide variety of applications, including tissue engineering scaffolds (repair/regeneration), wound healing, drug delivery carriers, bio-inks, soft robotics, sensors, actuators, catalysis, food safety, and hygiene products. This review is focused on recent advances in the field of bioinspired hydrogels that can serve as platforms for life-science applications. A brief outlook on the actual trends and future directions is also presented.

An injectable supramolecular nanofiber-reinforced chitosan hydrogel with antibacterial and anti-inflammatory properties as potential carriers for drug delivery

The inherent weak mechanical strength of chitosan physical cross-linking hydrogels (CS hydrogels) limits their applications in biomaterials. Hence, puerarin (PUE) as a self-assembly active small molecule in herbal was introduced in CS hydrogels to fabricate CS/PUE₁₈ composite hydrogels with interpenetrating network structure. The result of rheological measurement showed that storage modulus and loss modulus of CS/PUE₁₈ composite hydrogels were improved by three orders of magnitude, indicating that the introduction of PUE significantly reinforced CS hydrogels. The results of SEM and BET measurement demonstrated that macromolecular chains of CS intertwined with nanofibers of PUE, which caused the network structure of CS/PUE₁₈ composite hydrogels to become denser. XRD patterns and FT-IR spectra verified that the amino groups in CS formed hydrogen bonding with the hydroxyl groups in PUE. Degradation and swelling experiments showed that CS/PUE₁₈ composite hydrogels have pH sensitivity. Moreover, CS/PUE₁₈ composite hydrogels exhibited multi-functionality including injectability, thixotropy, cytocompatibility, antibacterial and anti-inflammatory properties. The release behavior of berberine chloride hydrate (BCH) and PUE from the resultant CS/PUE₁₈ composite hydrogels have pH dependence. These results revealed that injectable CS/PUE₁₈ composite hydrogels with dual antibacterial and anti-inflammatory properties could be potential delivery vehicles for sustained and controlled release.