Abstract

Metal oxide nanocomposites are increasingly being recognised as promising multifunctional materials with intrinsic antimicrobial properties. In this work, a green route was developed for synthesising, characterising, and determining the antimicrobial activity of tungsten oxide-molybdenum oxide nanocomposites in a water-solvated ethaline system as the templating medium. The composites synthesized were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). FTIR spectroscopy confirmed the M-O linkage formation while XRD revealed characteristic crystalline phases of WO3 and MoO3. SEM micrographs disclosed water incorporation altering architecture at the surface to create less dense sponge-like entities from dense aggregations. The antibacterial activity towards Escherichia coli and Staphylococcus aureus bacteria was assessed using disk diffusion and dilution broth methods. A clear dose dependency with enhanced inhibition was noted with superior composite prepared using the DES-water system. The 80:20% wt. The W:Mo composite exhibited significantly enhanced antibacterial activity through an additivity effect involving redox chemistry by molybdenum and ROS generation mediated by tungsten. These findings underscore the versatility of DES-water based solvent systems as green medium to synthesize nanomaterials with application potential towards healthcare and environmental remediation and combating antimicrobial resistances.

Key words: Deep eutectic solvent, Ethaline, Tungsten oxide, Molybdenum oxide, antimicrobial activity