Design and evaluation of a novel nano copper/chitosan-starch bio-composite on antimicrobial property and wound-healing efficacy

The development of multi-species biofilms in wounds is a serious health problem that primarily generates strong resistance mechanisms to antimicrobial therapy. Chitosan based composites are interesting bio composites with applications in wound restorations and coatings for artificial implants. However, the lack of antimicrobial activity restricts its further application. Thus, the purpose of this study is to prepare a novel chitosan based metal nanocomposite. Therefore, we report the green synthesis of nontoxic, stable, and small size copper nanoparticle by using chitosan/starch hydrogel with reducing/capping ability without any toxic reducing agents. Starch was used as a reducing agent for the synthesis of Cu NPs that next stabilized by chitosan polymers. The in situ prepared Cu NPs/CS-Starch bio-composite were characterized by advanced physicochemical techniques like Fourier Transformed Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD) study and inductively coupled plasma-optical emission spectroscopy (ICP-OES). It has been established that Cu NPs/CS-Starch bio-composite have a spherical shape with a mean diameter from 10 to 30 nm. The Cu NPs/CS-Starch bio-composite showed promising antimicrobial activity against various pathogens (Gram-negative, Gram-positive and fungus). In vivo design, Cu NPs/CS-Starch bio-composite ointment significantly (p <= 0.01) increase the levels of wound contracture, vessel, hydroxyl proline, hexuronic acid, hexosamine, fibrocyte, and fibroblast, and significantly (p <= 0.01) decrease the levels of wound area, total cells, neutrophil, and lymphocyte compared to other groups in rats. Moreover, a certain concentration of Cu NPs/CS-Starch bio-composite can improve the adhesion and proliferation of cells, which has also been proved in animal experiments, including gross appearance and histological observations. Together, these results suggest the efficacy of Cu NPs/CS-Starch bio-composite for broad applications associated with wound healing.