Covalent and biodegradable chitosan-cellulose hydrogel dressing containing microspheres for drug delivery and wound healing

The purpose of this study is to prepare polysaccharide-based hydrogel dressing integrated with microspheres which has excellent self-healing ability and sustained antibacterial function for wound healing application. The hydrogel is derived from carboxymethyl chitosan (CMCS) and carboxymethyl cellulose (CMC) via the Schiff’s base reaction, without the addition of chemical catalyst. Also, the CMCS microspheres containing an antibacterial drug, e.g., tetracycline hydrochloride (TH), were prepared by an emulsion cross-linking. Parameters were optimized during the preparation experiment to improve various properties of the microspheres/hydrogel composite dressing. This gel dressing has good elasticity, when compressive strain was 0.7 mm/mm, the tangent elastic modulus was up to 1.7 MPa. Furthermore, its drug sustained release performance was significantly better than the drug directly embedded in the hydrogel. TH could sustain release stably within 12 h, without obvious burst release phenomenon. Antibacterial experiments showed that 20 mg/mL microspheres made composite dressing a better performance than control microspheres and hydrogel. Potential of the composite scaffolds was further demonstrated by culture of human adipose-derived stem cells (ASCs) in vitro. Cell culture showed that this composite hydrogel could support survival and proliferation of ASCs. These characteristics provide a potential opportunity to use this composite gel dressing in drug delivery and wound healing applications.