Sustainable synthesis of gold-embedded ZnO nanoparticles from natural extract for environmental and biomedical applications

The presence of antibiotics in industrial wastewater poses a significant environmental challenge, threatening ecosystems and public health. This study explores a green and sustainable approach to address this issue by synthesizing gold-embedded zinc oxide nanoparticles using Amaranthus retroflexus leaf extract (A. retroflexus@Au-embedded ZnO NPs). The eco-friendly phenolic compounds present in the extract acted as natural reducing and stabilizing agents, eliminating the need for conventional chemical reducers. Comprehensive characterization using FT-IR, DLS, XRD, and TEM confirmed the high purity of the synthesized nanoparticles, with an average particle size ranging 45–65 nm. The nanoparticles exhibited excellent photocatalytic activity in degrading penicillin G under optimized conditions. In addition to their photocatalytic performance, the nanoparticles demonstrated remarkable anticancer activity against human gastric cancer (AGS) and human breast cancer (MCF-7) cell lines, enhanced antibacterial efficacy against both Gram-negative and Gram-positive bacteria, and significant antioxidant potential compared to pure ZnO. These findings highlight the multifunctional potential of A. retroflexus@Au-embedded ZnO NPs for applications in environmental remediation and biomedical fields.