Green synthesis of bimetallic Au@Pt nanostructures and their application for proliferation inhibition and apoptosis induction in human cervical cancer cell

Bimetallic Au@Pt nanostructures (Au@Pts) are potential candidates for optical, electrical, catalytic and biological applications. However, methods for the fabrication of Au@Pts using total tea polyphenols (TPPs), studies of the mechanism of action of Au@Pts on biological systems and studies on the application of Au@Pts in cancer diagnosis and therapy are sparse. In this study, we developed a simple, eco-friendly and low-cost method for the synthesis of Au@Pts to examine the cytotoxic effect of these Au@Pts on human cervical cancers in vitro. The gold and platinum ions were successfully reduced simultaneously using TPPs at room temperature. The prepared Au@Pts were characterized using UV-Vis spectrophotometery, X-ray diffractometery (XRD), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). EDS and XRD confirmed the formation of the Au@Pt. Formation of Au@Pts with a size of 5-20 nm was confirmed using TEM. The cytotoxic properties of the Au@Pts were evaluated in human cervical cancer cells (SiHa). The cell viability results revealed that Au@Pts induce cell death in a dose-and time-dependent manner. The morphological features of the Au@Pt-exposed SiHa cells were observed and indicated cell death via cell shrinkage, intranucleosomal DNA fragmentation and chromatin condensation. During progression of the different phases of the cell cycle, the proportion of cells in the G2/M phase of the treated SiHa cells was significantly increased, which strongly confirmed that the Au@Pts induced apoptosis through the G2/M phase check points. Our findings demonstrate the activity of Au@Pts against cervical cancer cells and reveal strategies for the development of highly active bimetallic nanostructures for cancer therapeutics.