The biosynthesis of a graphene oxide-based zinc oxide nanocomposite using Dalbergia latifolia leaf extract and its biological applications

Abstract

Green-synthesized zinc oxide nanoparticles (ZnO NPs) were fabricated with graphene oxide (GO) nanosheets (Hummers’ method) into a ZnO/GO nanocomposite (NC), and those materials were characterized via UV-Vis, FT-IR, XRD, SEM, EDX, TEM, DLS, and zeta potential studies. The UV-Vis spectra exhibited absorption peaks at around 372 nm for ZnO NPs, 233 nm for GO, and 275 and 385 nm for ZnO/GO NC, and the FT-IR spectra also confirmed the formation of ZnO (457 cm⁻¹), GO (1052 cm⁻¹) and ZnO/GO NC (458 cm⁻¹). XRD analysis of the synthesized nanomaterials revealed the hexagonal wurtzite structure of the ZnO NPs. SEM and TEM morphological studies showed that the ZnO NPs were spherical in shape, GO was found to have a sheet-like shape, and ZnO NP immersed nanosheets were seen in ZnO/GO NC. The antibacterial effects of the synthesized nanomaterials ZnO NPs, GO and ZnO/GO NC were assessed against human pathogens, and significant bacterial resistance was exhibited toward Staphylococcus aureus; in particular, ZnO/GO NC served as a potent antibacterial agent. In vitro cytotoxicity studies were conducted on cancer cells treated with ZnO NPs, GO and ZnO/GO NC using lung cancer cells (A549) and human breast cancer cells (MCF-7). MTT assays indicated the significant anticancer activity of ZnO/GO NC (IC₅₀: 15 μg mL⁻¹) against the MCF-7 cell line compared to the nanomaterials ZnO NPs (IC₅₀: 24 μg mL⁻¹) and GO (IC₅₀: 23 μg mL⁻¹). Thus, the study revealed that ZnO/GO NC produced through green synthesis has great potential to be developed into an efficient therapeutic agent against various cancers.