Bio-approach: Ureolytic bacteria mediated synthesis of ZnO nanocrystals on cotton fabric and evaluation of their antibacterial properties.

ZnO nanoparticles (NPs) synthesis on cotton fabric through the formation of biologically activated ammonia from urea broth in the presence of the ureolytic bacterial species Serratia ureilytica (HM475278) has been described in the present contribution. The cotton fabric was immersed in biogenic zinc ammonium complex medium and subjected to heat treatment at an optimum temperature of 50 °C for different durations of time (30, 60, 90 min). The crystal growth of ZnO nanoparticles on cotton fabric was characterized by analytical techniques such as SEM-EDAX, XRD, TGA, CHNS and UV-visible spectra, and evaluation of antibacterial activity was carried out against Escherichia coli and Staphylococcus aureus. Crystal growth and morphological studies confirmed the attachment of ZnO NPs on the cotton fabric. Spherical to nanoflower shaped particles were obtained with increasing time duration from 30 to 90 min. The antibacterial activity of loaded cotton fabrics was found to be substantially higher than the bare cotton samples. Wet film interfacial contact studies have shown greater antibacterial activity as a result of nanoparticle contact at the bio-interface, as observed by Epi-fluorescent microscopic observations.