Multifunctional Ag/ZnO. Nanocomposites: Synthesis, Characterization, and Potent Antioxidant, Antibiofilm, and Anti-Inflammatory Activities

Abstract

Ag/ZnO nanocomposites have attracted significant interest due to their enhanced physicochemical properties and wide-ranging biomedical applications. In this study, the nanocomposites were successfully synthesized and thoroughly characterized. X-ray diffraction confirmed the presence of a highly crystalline hexagonal ZnO structure with incorporated metallic Ag nanoparticles; the crystallite size, determined by the Scherrer equation, was approximately 55 nm. Scanning electron microscopy revealed quasi-spherical particles exhibiting uniform morphology and good dispersion. UV–Vis spectroscopy displayed a prominent absorption band at 383 nm and a narrowed optical band gap of 1.70 eV, indicating strong electronic interactions between Ag and ZnO, along with improved surface reactivity. Biological evaluation demonstrated potent multifunctional activities. In the DPPH assay, the nanocomposites showed concentration-dependent antioxidant activity, achieving 79% radical scavenging at 400 µg/mL, with an IC₅₀ of 166.79 µg/mL. The FRAP assay confirmed strong reducing power, rising from 120.22 to 760.37 µM Fe²⁺/g with increasing concentration. The materials exhibited excellent antibiofilm effects against pathogenic bacteria, inhibiting biofilm formation by up to 90%. Additionally, they effectively inhibited protein denaturation in the anti-inflammatory assay, yielding an IC₅₀ of 137.83 µg/mL. These findings underscore the substantial biomedical potential of Ag/ZnO nanocomposites.