Green synthesis of ZnO nanoparticles using Pachyrhizus erosus extract: Structure–function relationships and antibacterial performance

Green synthesis of ZnO–PEE nanocomposites via Pachyrhizus erosus (PEE) extract provides a sustainable, standardized route to high-performance nanomaterials. This study establishes the structure-function relationship governing their antibacterial efficacy. We synthesized ZnO–PEE nanocomposites with varying precursor concentrations and evaluated their physicochemical properties. XRD patterns confirm a phase-pure hexagonal wurtzite structure, with an optimal crystallite size of 33.33 nm (achieved at 0.1 M precursor), which maximizes surface-area-to-volume ratio while limiting particle agglomeration. FTIR and UV-vis data verify bio-functionalization by PEE-derived phytochemicals, which promote charge transfer and modulate bacterial oxidative stress. DLS analysis shows that sonication effectively reduces particle size, improving colloidal stability. ZPE-0.1 achieved 99.43% antibacterial efficiency against Staphylococcus aureus at 1000 ppm, outperforming pure ZnO. These results demonstrate that precisely tuning ZnO morphology through phytochemical-assisted synthesis directly dictates antibacterial performance, establishing ZPE-0.1 as an optimized antimicrobial agent for biomedical applications.