In situ deposition of nano Cu2O on electrospun chitosan nanofibrous scaffolds and their antimicrobial properties

In order to obtain a synergistic antimicrobial effect of cuprous oxide nanoparticles (Cu2O NPs) and chitosan (CS) nanofibers, the nano Cu2O/CS nanofibrous scaffolds were synthesized in situ via two subsequent steps of chelation and reduction. The Cu2+ were stably chelated on CS nanofibrous scaffolds through the coordination of amino group (-NH2) and hydroxyl group (-OH) on CS with Cu2+, and then the chelated Cu2+ were reduced to nano Cu2O by Vitamin C under alkaline conditions. And by the measurements of XRD, XPS and FTIR-ATR, the results showed that Cu2O NPs were successfully deposited on the CS nanofibrous scaffolds. SEM clarified that the particle size of Cu2O gradually decreased and the shape changed from cubic to irregular with the increase of CuSO4 concentration. With the CuSO4 concentration of 0.02 and 0.04 mol·L-1, the Cu2O/CS nanofibrous scaffolds presented outstanding hydrophilicity and antibacterial activity against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) comparing to the CS nanofibrous scaffolds, meanwhile, they possessed good biocompatibility. This kind of nanofibrous scaffolds deposited with nano Cu2O would have broad application prospects in the field of antibacterial biomaterials.