Rod-shaped gold nanoparticles biosynthesized using Pb²⁺-induced fungus Aspergillus sp. WL-Au

Gold nanoparticles (AuNPs) attracted much attention owing to their distinguished characteristics and applications. In this study, rod-shaped AuNPs were biosynthesized using Pb²⁺-induced fungus Aspergillus sp. The synthesized AuNPs showed a UV-vis absorption peak at 534 nm. Scanning electron microscopy and transmission electron microscopy analyses showed that rod-shaped AuNPs were biosynthesized and attached on the mycelia surfaces. Energy-dispersive spectrometer analysis identified gold as the unique metallic composition of synthesized nanoparticles. X-ray powder diffraction analysis showed that the AuNPs were face-centered cubic crystalline structure. Furthermore, Fourier transform infrared spectroscopy analysis detected functional groups, including C = O, C-O-C, amine I and II which played active roles in AuNPs formation. In addition, the main shape of synthesized AuNPs changed from sphere to rod-shape with the increase of biomass and Pb²⁺ concentration. This study reports quite uniform rod-shaped AuNPs biosynthesized using Pb²⁺-induced fungus Aspergillus sp. WL-Au for the first time. This will provide a valid alternative for oriented biosynthesis of AuNPs.