Green synthesis and characterization of copper nanoparticles using Phragmanthera austroarabica extract and their biological/environmental applications

Abstract

In the current scenario, the use of phytochemicals from the extracts of plants has become a unique approach for the biosynthesis of metallic nanoparticles because of their dual nature of capping and as reducing agents for the metallic nanoparticles. The current work describes a green method for the biosynthesis of copper nanoparticles (CuNPs) using extract of Phragmanthera austroarabica (P. austroarabica). The conditions of green synthesis were optimized to produce ideal size range for CuNPs. CuNPs were observed to have spherical and crystalline nature with particle size of 44.6 ± 2.7 nm, as confirmed by XRD, SEM, and TEM results. The fluorescence technique demonstrated that CuNPs are highly efficient probes for the detection of hexavalent chromium ions (Cr (VI)), with a limit of detection (LOD) of 1.20 nM, which is one of the lowest LODs reported for sensing substances. The CuNPs also exhibited excellent degradation efficiency for the industrial organic dyes, i.e., congo red (95.75% removal in 7 min) and methylene blue (96.67% removal in 11 min) with rate constants of 0.4829 and 0.3276 min−1, respectively. Furthermore, the results indicated that the CuNPs have high antioxidant activity. The cytotoxicity assay on human breast cancer cells (MDA-MB-231) also showed that CuNPs inhibited the growth of MDA-MB-231 cells with a half maximal inhibitory concentration (IC50) of 66.74 μg/mL, suggesting that the biosynthesized CuNPs may be a good potential therapeutic agent for human breast cancer treatment. CuNPs showed highly efficient antibacterial and antifungal effects against Staphylococcus aureus, Escherichia coli, Penicillium chrysogenum and Fusarium oxysporum. This is the first work reported on P. austroarabica plant mediated biosynthesis of CuNPs, and we believe that these results may pave the way for a new direction in the field of nanotechnology and nanomedicine. Hence, CuNPs may be potent agents in various environmental and biomedical applications that are yet to be explored in near future.