Green electrospun nanocuprous oxide-poly(ethylene oxide)-silk fibroin composite nanofibrous scaffolds for antibacterial dressings

Cuprous oxide (Cu2O) nanoparticles have attracted extensive attention because of their excellent optical, catalytic, antibacterial, and antifungal properties and low cost. Nano-Cu2O-poly(ethylene oxide) (PEO)-silk fibroin (SF) composite nanofibrous scaffolds (CNSs) were fabricated through green electrospinning to impart excellent antibacterial properties onto nanofibrous scaffolds. Scanning electron microscopy revealed that the nanofibers became more nonuniform and appeared more and more as beads in the nanofibers with increasing nano-Cu2O concentration, and no obvious morphological changes were observed after 75% EtOH vapor treatment. Transmission electron microscopy and X-ray photoelectron spectroscopy demonstrated that nano-cuprous oxide (nano-Cu2O) was successfully loaded into the PEO-SF nanofibers. Fourier transform infrared-attenuated total reflectance spectroscopy results indicate that nano-Cu2O did not induce SF conformation from random coils to beta sheets. The SF conformation converted from random coils to beta sheets after 75% EtOH vapor treatment. The results of water contact angle testing and swelling property measurement clarified that nano-Cu2O-PEO-SF CNSs possessed outstanding hydrophilicity. Nano-Cu2O-PEO-SF CNSs exhibited better antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria than PEO-SF nanofibrous scaffolds, and the antibacterial activity increased with increasing nano-Cu2O concentration. Cell viability studies with pig iliac endothelial cells demonstrated that nano-Cu2O-PEO-SF CNSs had no cytotoxicity. Nano-Cu2O-PEO-SF CNSs are expected to be ideal biomimetic antibacterial dressings for wound healing. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47730.