Synthesis and Characterization of Quercetin-Functionalized Gold Nanoparticles for Screening Anticancer Potentials: A Flow Cytometry Approach

The gold nanoparticles (AuNPs) were synthesized via the Turkevich-Frens approach, conjugated with polyphenol moieties named quercetin (Qu), and prepared as Au-Qu NPs. In this study, we investigated the anticancer activity of the Au-Qu NPs through an apoptosis assay and a live/dead staining assay. The cell viability and apoptosis studies of the synthesized AuNPs and Au-Qu NPs were investigated on mouse embryonic fibroblast cells (NIH/3T3) and human cervical cancer cell lines (HeLa). Interestingly, minimal cytotoxicity was observed in 3T3 cells. Also, an apoptosis assay was conducted using the flow cytometry approach to investigate the cell death in both 3T3 and HeLa cells after the treatment of AuNPs and Au-Qu NPs using Annexin-FITC and propidium iodide (PI) dyes. The apoptosis studies were performed in both 3T3 and HeLa cells, and the Au-Qu NPs exhibited a reasonably increased apoptosis of 34.5% in HeLa cells as compared to AuNPs in HeLa cells (32.2%). Thus, the Au-Qu NPs are more suitable for investigating anticancer properties than AuNPs. In addition, Au-Qu NPs are displaying less early apoptosis (40.5%) than AuNPs (54.7%) in 3T3 cells, which suggests that Au-Qu NPs are biocompatible in healthy cells. The live/dead assay results obtained in 3T3 and HeLa cells in a time-dependent manner (0, 6, 12, and 24 h) have demonstrated the potential cell viability and cell toxicity in response to AuNPs and Au-Qu NPs.