Injectable, self-healing, antibacterial, and hemostatic N,O-carboxymethyl chitosan/oxidized chondroitin sulfate composite hydrogel for wound dressing.

Biodegradable and injectable hydrogels derived from natural polysaccharides have attracted extensive attention in biomedical applications due to their minimal invasiveness and ability to accommodate the irregular wound surfaces. In this work, we report the development of an in-situ-injectable, self-healing, antibacterial, hemostatic, and biocompatible hydrogel derived from the hybrid of N,O-carboxymethyl chitosan (N,O-CMC) and oxidized chondroitin sulfate (OCS), which did not require any chemical crosslinking. The N,O-CMC/OCS hydrogel could be readily produced under physiological conditions by varying the N,O-CMC-to-OCS ratio, relying on the Schiff base reaction between the -NH- functional groups of N,O-CMC and the -CHO functional groups of OCS. The results showed that the N,O-CMC2/OCS1 hydrogel had relatively long gelation time (133 s) and stable performances. The viability of NIH/3T3 cells and endothelial cells cultured with the N,O-CMC2/OCS1 hydrogel extract was roughly 85%, which demonstrated its low cell toxicity. Besides, the N,O-CMC2/OCS1 hydrogel revealed excellent antibacterial properties due to the inherent antibacterial ability of N,O-CMC. Importantly, the hydrogel tightly adhered to the biological tissue and demonstrated excellent in vivo hemostatic performance. Our work describing an injectable, self-healing, antibacterial, and hemostatic hydrogel derived from polysaccharides will likely hold good potential in serving as an enabling wound dressing material.