Tendon-inspired hybrid hydrogel based on polyvinyl alcohol and gallic acid-lysozyme for promoting wound closure and healing.

Noninvasive wound closure remains a challenge in the field of wound healing. In this study, we report the development of a cross-linked P-GL hydrogel constructed from polyvinyl alcohol (PVA) and GL (a hydrogel consisting of gallic acid and lysozyme) that effectively promotes wound closure and healing. The P-GL hydrogel exhibited a unique lamellar and tendon-like fibrous network structure, providing good thermo-sensitivity and tissue adhesiveness up to 60 MPa, as well as retaining autonomous self-healing and acid resistance capacities. In addition, the P-GL hydrogel exhibited sustained release characteristics lasting >100 h, excellent biocompatibility both in vitro and in vivo, as well as good antibacterial activity and mechanical properties. The in vivo full-thickness skin wounds model revealed the positive wound closure and healing therapeutic effects of the P-GL hydrogels were confirmed, showing a promising potential as a noninvasive wound closure and healing bio-adhesive hydrogel.

Mucoadhesive Hydrogel with Anti-gastric Acid and Sustained-Release Functions for Amelioration of DSS-Induced Ulcerative Colitis.

Mucoadhesive hydrogels with multifunctional properties such as gastric acid resistance and sustained drug release in the intestinal tract are highly desirable for the oral treatment of inflammatory bowel diseases (IBDs). Polyphenols are proven to have great efficacies compared with the first-line drugs for IBD treatments. We recently reported that gallic acid (GA) was capable of forming a hydrogel. However, this hydrogel is prone to easy degradation and poor adhesion in vivo. To tackle this problem, the current study introduced sodium alginate (SA) to form a gallic acid/sodium alginate hybrid hydrogel (GAS). As expected, the GAS hydrogel showed excellent antiacid, mucoadhesive, and sustained degradation properties in the intestinal tract. In vitro studies demonstrated that the GAS hydrogel significantly alleviated ulcerative colitis (UC) in mice. The colonic length of the GAS group (7.75 ± 0.38 cm) was significantly longer than that of the UC group (6.12 ± 0.25 cm). The disease activity index (DAI) value of the UC group was (5.5 ± 0.57), which was markedly higher than that of the GAS group (2.5 ± 0.65). The GAS hydrogel also could inhibit the expression of inflammatory cytokines, regulating macrophage polarization and improving the intestinal mucosal barrier functions. All these results indicated that the GAS hydrogel was an ideal candidate for oral treatment of UC.

Construction of an antibacterial hydrogel based on diammonium glycyrrhizinate and gallic acid for bacterial- infected wound healing.

The current antibacterial wound dressings with antibiotic substances or metal bactericidal agents may lead to severe multidrug resistance and poor biocompatibilities. Herein, we report an inherent antibacterial hydrogel constructed by only two naturally small molecules gallic acid (GA) and diammonium glycyrrhizinate (DG) for promoting Staphylococcus aureus (S. aureus)-infected wound healing. The resultant GAD hydrogel can be fabricated by co-assembly of these two materials through simple steps. Thanks to the incorporation of GA and DG, GAD hydrogel enabled a strong mechanical performance and great self-healing property with a sustained-release of drugs into skin wounds. Moreover, the cell viability assays showed that GAD hydrogel had good cytocompatibility by promoting cell proliferation and migration. In addition, GAD hydrogel had broad antibacterial efficiency against both Gram-positive and Gram-negative bacteria. Taken together, GAD hydrogel is a promising dressing to accelerate bacterial-infected wound healing through reconstructing an intact and thick epidermis without antibiotics or cytokines.

Construction of a sustained-release hydrogel using gallic acid and lysozyme with antimicrobial properties for wound treatment.

The purpose of this study is to provide a new strategy for constructing a temperature-controlled hydrogel as a promising agent for wound healing using natural products through physical co-assembly. Herein, the temperature-controlled physically assembled hydrogel consisting of gallic acid and lysozyme (GL) could be co-assembled into a regular fibrous structure accompanied by strong blue fluorescence with three-dimensional networks at micron levels through hydrophobic interactions, π-π interactions and hydrogen bonding. This GL hydrogel has excellent temperature sensitivity and self-healing properties, as proved by cycle high-low temperature tests. In addition, it possesses stable rheological properties, great sustained release ability, and could realize the spatiotemporal delivery of gallic acid and lysozyme. Biocompatibility and antibacterial tests proved that this well-assembled GL hydrogel has no cytotoxicity but excellent antibacterial activity. Both in vitro and in vivo experiments demonstrated that the GL hydrogel has excellent anti-inflammation efficiency and promotes the healing of chronic wounds by suppressing the expression of pro-inflammatory related genes. Tests using an E. coli-infected wound model confirmed that the GL hydrogel could terminate the inflammatory phase early and ultimately promote the healing of wounds infected by E. coli. This study provides a promising strategy for the effective treatment of wounds through a physical self-assembled hydrogel.