Copper nanowire embedded hypromellose: An antibacterial nanocomposite film

The present work reports a novel antibacterial nanocomposite film comprising of copper nanowire impregnated biocompatible hypromellose using polyethylene glycol as a plasticiser. Detailed physicochemical characterization using X-ray diffraction, Fourier transform infrared spectroscopy, UV-Visible spectroscopy and electron microscopy shows uniform dispersion of copper nanowire in the polymer matrix without any apparent oxidation. The film is flexible and shows excellent antibacterial activity against both Gram positive and negative bacteria at 4.8 wt% nanowire loading with MIC values of 400 mu g/mL and 500 mu g/mL for E. coli and S. aureus respectively. Investigation into the antibacterial mechanism of the nanocomposite indicates multiple pathways including cellular membrane damage caused by released copper ions and reactive oxygen species generation in the microbial cell. Interestingly, the film showed good biocompatibility towards normal human dermal fibroblast at minimum bactericidal concentration (MBC). Compared to the copper nanoparticles reported earlier in vitro studies, this low cytotoxicity of copper nanowires is due to the slow dissolution rate of the film and production of lower amount of ROS producing Cu2+ ions. Thus, the study indicates a strong potential for copper nanowirebased composites films in broader biomedical and clinical applications. (C) 2021 Published by Elsevier Inc.

Automated summary

A novel antibacterial nanocomposite film containing copper nanowires was successfully fabricated in this study, showing excellent antibacterial activity and good biocompatibility towards human dermal fibroblast. The slow dissolution rate of the film and production of lower amount of ROS producing Cu2+ ions contribute to the low cytotoxicity of copper nanowires, indicating a strong potential for broader biomedical and clinical applications.