Eco-friendly Synthesis of Gold Nanoparticles and Evaluation of Their Cytotoxic Activity on Cancer Cells

We herein present a simple, clean, eco-friendly and inexpensive method for green synthesis of gold nanoparticles (AuNPs) using water extract from galls of Rhus chinensis. In this study, the reactions were conducted at 50 °C for 15 min using a magnetic stirrer and water as a solvent. AuNP characterization was performed using ultraviolet–visible (UV–vis) spectroscopy, transmission electron microscopy, field-emission scanning electron microscopy, and X-ray diffraction analysis. Element composition was detected via energy dispersive X-ray analysis. The possible presence of functional groups was analyzed using Fourier-transform infrared spectroscopy. The synthesized AuNPs exhibited a color change to wine red and a UV–vis peak at 532 nm. The sizes of AuNPs ranged from 20 to 40 nm, and they had oval and spherical shapes. The cytotoxic effects against MKN-28 (Adenocarcinoma), Hep3B (Heptocellular carcinoma), and MG-63 (Osteosarcoma) cells were evaluated using tetrazolium-based assay. The AuNPs induced cytotoxicity in a dose-dependent manner, and morphology upon cell death was differentiated via fluorescent microscopy using 4,6-Diamidino-2-pheynylindole dihydrochloridehydrate staining which predicted apoptosis.