Waste fruit peel – Mediated green synthesis of biocompatible gold nanoparticles

Abstract

Gold nanoparticles (AuNPs) have many applications in biomedical science due to their small size, large surface area, inertness, stability, high dispersity, and biocompatibility. However, the preparation of biocompatible and non-toxic AuNPs is very important issue. Biological synthesis of AuNPs presents to be simple, cost-effective, and non-toxic, which is unlike the chemically synthesized AuNPs. The aim of this study was to synthesize biocompatible AuNPs using waste fruit peel. We developed green method for AuNP synthesis by reducing gold (III) chloride trihydrate (HAuCl4) with an aqueous fruit peel extract of Ananas comosus (pineapple) and Passiflora edulis (passion fruit). Such fruit peels are usually considered a waste material but contain many chemical components including proteins, minerals, lipids, vitamin, phenolic compounds, flavonoids and carotenoid, which act as reductants and nanoparticle stabilizers. Gold nanoparticles obtained using pineapple peel (Pi-AuNPs) and passion fruit peel extracts (Pa-AuNPs) exhibit a characteristic red coloration and UV–visible spectral absorption maximum around 545 nm attributable to surface plasmon resonance. TEM imaging confirmed that the AuNPs were spherical, with XRD patterns indicating that the gold atoms adopt a face-centered cubic structure. Cell viability assays in normal African green monkey kidney epithelial cells (Vero) and breast cancer cells (MCF-7) imply that the synthesized AuNPs have no biological cytotoxicity, even at high concentration (400 μg/mL). This study thus highlights the potential benefit of employing fruit peel extracts as reducing and stabilizing agents for the synthesis of non-cytotoxic AuNPs, with the greenness of the production process being particularly important for their utility in biomedical applications.