Physicochemical and therapeutic studies of microwave-synthesized ZnO and Cr-doped ZnO nanoparticles for biomedical applications

Abstract

Highly stable Zinc Oxide (ZnO) and Chromium (Cr) doped ZnO nanoparticles (NPs) are increasingly studied for biomedical applications due to their low toxicity, biodegradability, and affordability. In this paper, ZnO NPs and Cr doped ZnO NPs have been prepared by a microwave method. The prepared samples were studied with their physicochemical characteristics and successively investigated their impact on the antimicrobial, antioxidant, and biocompatibility properties. Correlations between physicochemical and biomedical properties were assessed. The NPs demonstrated strong, concentration-dependent antibacterial effects against E. coli and X. citri, with maximum inhibition zones of 15.53 mm (PZnO), 13.33 mm (CZnO), 13.56 mm (ZCr2), 14.03 mm (ZCr4), and 15.0 mm (ZCr6) for E. coli, and 13.73, 13.46, 14.50, 14.70, and 15.26 mm, respectively, for X. citri. They also showed significant antifungal activity against A. niger and R. stolonifer. Antioxidant activity, measured via DPPH radical scavenging, revealed inhibition rates of 58.52–92.27 % (PZnO), 56.27–90.65 % (CZnO), 51–85 % (ZCr2), 54–87 % (ZCr4), and 57.75–87.59 % (ZCr6). Hemolysis assays indicated biocompatibility, with hemolysis percentages below 5 % for all NPs at concentrations up to 500 µg/mL. These findings suggest that ZnO and Cr doped ZnO NPs are promising candidates for biomedical applications, offering antimicrobial and antioxidant properties with minimal toxicity to human erythrocytes.