Antimicrobial poly(vinyl alcohol) cryogel-copper nanocomposites for possible applications in biomedical fields

This study explores the in situ fabrication of poly(vinyl alcohol) (PVA) cryogel-copper nanocomposites in view of their increasing applications as antimicrobial packaging, wound dressing and antibacterial materials. The reduction of copper ions into copper nanoparticles was achieved using hydrazine hydrate as reducing agent. The PVA cryogel-copper nanocomposites were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), Raman spectroscopy, inductively coupled plasma-atomic emission spectrometry, thermogravimetric analysis and X-ray diffraction (XRD) analysis. The scanning electron microscopic images illustrated the presence of embedded copper nanoparticles throughout the network and the copper nanoparticles were found to have an average particle size of around 20nm as observed by TEM. The XRD results showed all relevant Bragg's reflections for crystal structure of copper nanoparticles. Mechanical properties of nanocomposites were observed in terms of tensile strength and strain at break (%). The PVA cryogel-copper nanocomposites demonstrated significant antibacterial effects against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Vibrio cholerae and Gram-positive bacilli. The prepared PVA cryogel-copper nanocomposites were also evaluated for their water uptake potentials and deswelling behaviours. The swelling experiments were performed for prepared nanocomposites of varying compositions at different pH and temperatures. The in vitro biocompatibility of the prepared nanocomposites was determined by per cent haemolysis and protein (BSA) adsorption tests. Thus, this study may provide novel antibacterial nanocomposites which may potentially be useful in preventing/treating various infections.