Graphene oxide coated shell-core structured chitosan/PLLA nanofibrous scaffolds for wound dressing

Graphite oxide (GO) and chitosan (CS) nanofibers have aroused intense interest as wound dressing due to their physicochemical, antimicrobial properties and nanotopography. In this study, GO nanosheets were coated on shell (chitosan, CS)-core (L-polylactic acid, PLLA) structured nanofibrous scaffolds to create a synergistic microenvironment for wound healing. Through scanning electron microscopy (SEM) and atomic force microscopy (AFM) tests, results showed that the surface of GO-coated CS/PLLA nanofibers presented corrugated wrinkles and rougher than that of CS/PLLA nanofibers, and the GO nanosheets did not destroy the structure of nanofibers. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) demonstrated that GO nanosheets were successfully coated on CS/PLLA nanofibrous scaffolds. Furthermore, the coatings of GO nanosheets significantly improved the hydrophilicity of CS/PLLA nanofibrous scaffolds. GO-coated CS/PLLA nanofibrous scaffolds revealed more excellent antimicrobial activity to Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) than that of CS/PLLA nanofibrous scaffolds, meanwhile, they promoted the proliferation of pig iliac endothelial cells (PIECs). Rats wounds covered by GO-coated CS/PLLA nanofibrous scaffolds were healed better than other groups on pathological section. This type of nanofibrous scaffolds with GO nanosheets would possess an excellent potential in wound healing process.