PEG-functionalized ZnO nanoparticles synthesized by Co-precipitation for improved antibacterial performance

Zinc oxide nanoparticles (ZONPs) have attracted substantial attention in biomedical applications because of their potent antibacterial properties, primarily attributed to their ability to generate reactive oxygen species and interact with microbial membranes. In the present research work, ZONPs were synthesized using the co-precipitation method and subsequently modified with urea and varied polyethylene glycol to enhance their physicochemical and antibacterial properties. The influence of varying PEG concentrations (0.1, 0.3, and 0.5 g) on the structural, morphological, and optical properties, and their antibacterial efficacy of ZnO was systematically investigated. Structural, morphological, and optical characterizations were performed through X-ray diffraction, Raman spectroscopy, Field emission scanning electron microscopy (FESEM) with EDX, and UV–Visible spectroscopy. The antibacterial efficacy was measured by using Agar well method. The synthesized ZONPs exhibited well-defined crystallinity with surface modifications influenced by PEG content. Among the different PEG loadings, the sample prepared with 0.3 g PEG showed improved surface morphology and higher ROS generation compared to those obtained with 0, 0.1, and 0.5 g PEG. Antibacterial assessment at 1 mg/mL revealed inhibition zones of 16 mm against Staphylococcus, 14 mm against Bacillus, 13 mm against Klebsiella, and 12 mm against E. coli, indicating effective broad-spectrum activity.