Eggshell membrane-mediated V2O5/ZnO nanocomposite: synthesis, characterization, antibacterial activity, minimum inhibitory concentration, and its mechanism

The novel V2O5/ZnO nanocomposite, an antibacterial material, was synthesized through a simple, low-cost, and energy-saving approach. The eggshell membrane was used for the first time as a bio-template, reducing and stabilizing agent during this synthesis. Ammonium metavanadate and zinc nitrate hexahydrate (1:1) were the metal precursors. The synthesis involved soaking of an eggshell membrane with the metal solution at room temperature followed by the calcination. The as-prepared and synthesized V2O5/ZnO nanocomposite was characterized by thermal, spectroscopic, and microscopic techniques. Besides, this study determined the antibacterial activity (agar well-diffusion test) and minimum inhibition concentration (resazurin microdilution test) of V2O5/ZnO nanocomposite against Gram-positive bacteria (Staphylococcus aureus and Bacillus sp.) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella enterica, and Vibrio sp.). The annealing temperature (550 degrees C) for V2O5/ZnO nanocomposite was determined by the TGA-DTA study. The XRD analysis of V2O5/ZnO nanocomposite revealed the formation of both the orthorhombic (V2O5) and hexagonal wurtzite (ZnO) structures with the crystallite size of 20 nm. The FT-IR spectrum indicated the stretching vibration of V=O and Zn-O at 925 and 473 cm(-1), respectively. The Raman spectra also confirmed the formation of the orthorhombic and hexagonal wurtzite structure. From DRS UV-visible spectroscopy, the optical band-gap energy of V2O5/ZnO nanocomposite was equal to 2.05 eV. The HR-SEM study of V2O5/ZnO nanocomposite depicted large spheres as well as small particles. The EDX analysis established only vanadium (32.45 wt %), oxygen (57.06 wt %), and zinc (10.48 wt %). The zeta-potential analysis of V2O5/ZnO nanocomposite showed moderate stability with a negative value of - 42.9 mV. The study of antibacterial activity exhibited a high zone of inhibition (23 mm) against the Staphylococcus aureus and Bacillus sp. at 30 mu g mL(-1), and the minimum inhibition concentration (MIC) value was observed in Bacillus sp. at 0.49 mu g mL(-1). The V2O5/ZnO nanocomposite can be employed in biomedical applications as an antibacterial agent.