A novel green-mediated approach of 3-D hierarchical-like ZnO@Ag, ZnO@Au and ZnO@Ag@Au NCs prepared via Opuntia ficus indica fruits extract for enhancement of biological activities

In the present work, deposition of silver (Ag) and gold (Au) on zinc oxide (ZnO) NPs was synthesized via simple green-mediated approach by using plant extract of Opuntia ficus indica fruits which significantly improved the biological activity for biomedical application. The crystalline nature of synthesized nanocomposites was characterized by powder X-ray diffraction studies. The average sizes of the particles and surface morphologies were investigated from field emission scanning electron microscopy and transmission electron microscopy (TEM) analysis. The synthesized ZnO@Ag (SA-1), ZnO@Au (SA-2) and ZnO@Ag@AuNCs (SA-3) exhibited excellent antibacterial activity due to their interfacial charge-transfer kinetic in semiconductor (ZnO) and metal (Ag and Au). Thus, the result demonstrates that the synthesized materials have a potential candidate for antimicrobial applications in the fields of biomedicine and environmental protection.