Green Synthesis of ZnO Nanoparticles for Controlled Oxytetracycline Delivery and Synergistic Antibacterial Activity Against Klebsiella pneumoniae

ABSTRACT

Zinc oxide (ZnO) nanoparticles are promising nanocarriers for antibiotics due to their wide array of physicochemical properties. Green synthesis of ZnO nanoparticles using plant extract is a novel approach, simple, fast, and eco‐friendly. Therefore, the present study aimed to synthesize ZnO nanoparticles using an aqueous extract of Matricaria pubescens and to investigate their potential as a delivery platform for oxytetracycline (OXY) to combat antibiotic resistance in the Gram‐negative bacterium Klebsiella pneumoniae. The biosynthesized ZnO nanoparticles exhibited a characteristic UV–vis absorption at 372 nm, confirming ZnO formation. FT‐IR analysis indicated a pure ZnO phase, while XRD revealed a hexagonal wurtzite structure with an average crystallite size of 11.54 nm. SEM images showed irregular, aggregated nanoparticles. OXY loading was achieved via adsorption, with a multilayer mechanism consistent with Freundlich behaviour. The formation of coordination complexes between OXY and released Zn ^{2 +} ions was observed. Drug release studies demonstrated an initial fast release (60% within 30 min), followed by a sustained release. Hemolysis assays confirmed good hemocompatibility of ZnO and OXY‐loaded ZnO nanoparticles. Moderate antioxidant activity was observed using the DPPH assay. OXY‐loaded ZnO nanoparticles exhibited enhanced antibacterial activity against OXY‐resistant Klebsiella pneumoniae due to synergistic effects.