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Photocrosslinked hydrogels show great potential as dressings for skin wound healing. However, most current hydrogels suffer from poor adhesion, toxic photoinitiators, and insufficient versatility. Therefore, developing novel hydrogel dressings with appropriate properties is of great importance to accelerate the wound healing process. In this study, we developed a polysaccharide-based dual-network hydrogel consisting of azide-functionalized carboxymethyl chitosan and o-nitrobenzyl-modified hyaluronic acid (CMC-AZ/HA-NB). The hydrogel showed excellent mechanical, tissue adhesion, and water retention properties. Controllable in situ photocrosslinking was carried out without photoinitiator, avoiding issues associated with the cytotoxicity of photoinitiators. An antibacterial agent-loaded hydrogel (CMC-AZ/HA-NB@D) showed enhanced antibacterial properties. In addition, the CMC-AZ/HA-NB@D hydrogel promoted collagen deposition and vascular formation, as well as reducing the expression of pro-inflammatory factors, thereby accelerating the wound healing process and improving skin regeneration. The present results highlight the promising potential of multifunctional photoinitiator-free polysaccharide hydrogels for application in wound dressings.

Hydrogel tissue adhesives that currently available are often fabricated by mixing two or more polymeric components. Single-component hydrogels afford injectability, strong and reversible adhesion remain a formidable challenge. This research describes the creation of the first single-component hyaluronic acid hydrogel adhesive-based on phenylboronic acid-diol ester linkages. Phenylboronic acid can not only serve as a cross-linker to form hydrogel, but also act as an adhesion site for glycosyl compounds found in biological cell membranes. The rheological and compressive tests for the hydrogel show that it has excellent self-healing properties, good injectability and strong compressive strength. Adhesion tests demonstrated that the hydrogel has significantly greater adhesion strength than commercial fibrin glue. These findings suggest that the rational design of hydrogel precursors facilitates the formation of single-component networks and multiple functionalities. In vivo studies further proved the hydrogel was an ideal bio-adhesive with biocompatibility, absorbed wound exudate and hemostasis, and accelerated wound closure.

Effective wound dressings are of great significance in preventing infections and promoting wound healing. However, most existing hydrogel dressings have an inadequacy in either mechanical performance, biological activities, or versatilities. Here we presented a double-network cross-linked polysaccharide-based hydrogel composed of collagen peptide-functionalized carboxymethyl chitosan (CS) and oxidized methacrylate sodium alginate (SA). The hydrogel possessed interconnected porous morphologies, suitable swelling ratios, excellent mechanical properties, and favorable biocompatibility. Meanwhile, the in vivo studies using a mouse full-thickness skin defect model showed that the double-network CS/SA hydrogel significantly accelerated wound healing by regulating the inflammatory process, promoting collagen deposition, and improving vascularization. Therefore, the functionalized double-network hydrogel should be a potential candidate as wound dressings.

An integrated gene nanovector capable of overcoming complicated physiological barriers in one vector is desirable to circumvent the challenges imposed by the intricate tumor microenvironment. Herein, a nuclear localization signals (NLS)-decorated element and an iRGD-functionalized element based on O-carboxymethyl chitosan were synthesized, mixed, and coated onto PEI/DNA to fabricate bacterium-mimicking sequentially targeted therapeutic nanocomplexes (STNPs) which were internalized through receptor-mediated endocytosis and other pathways and achieved nuclear translocation of DNA. The endo/lysosomal membrane disruption triggered by reactive oxygen species (ROS) after short-time illumination, together with the DNA nuclear translocation, evoked an enhanced gene expression. Alternatively, the excessive ROS from long-time irradiation induced apoptosis in tumor cells, bringing about greater anti-tumor efficacy owing to the integration of gene and photodynamic therapy. Overall, these results demonstrated bacterium-mimicking STNPs could be a potential candidate for tumor treatments.