Green (gemini) surfactant mediated gold nanoparticles green synthesis: Effect on triple negative breast cancer cells

In this paper, we report the synthesis of gold nanoparticles (AuNPs) using the aqueous neem (Azadirachta indica) fruit extract as a reducing agent and capped by two different capping agents (monomeric surfactant: hexadecyltrimethylammonium chloride (CTAC) and dimeric counterion coupled gemini surfactant (COCOGS): 1, 6-Bis (N,N-hexadecyl dimethylammonium) adipate (16-6-16)). The synthesized AuNPs have been characterized by different modern techniques such as, UV–Visible spectroscopy, HR-TEM, DLS, XRD, FTIR, and XPS analyses, etc. The FTIR measurements were used to evaluate the adsorption of CTAC and COCOGS on the AuNPs surface. A significant shift in the stretching vibrations of CTAC and COCOGS head functional groups suggested their orientation towards the AuNPs surface and was further supported by the high-resolution XPS spectra of CTAC and COCOGS on the AuNPs surface. The main objective of the work is to investigate how to achieve the stability and activity of COCOGS-AuNPs for developing novel anticancer agents against triple negative breast cancer cells (TNBC). Hence, we have synthesized CTAC-AuNPs and COCOGS-AuNPs and evaluated theirs in vitro cytotoxicity against TNBC cell line (MDA-MB-231) as well as in normal NIH3T3 cells. The synthesized COCOGS-AuNPs displayed the excellent cytotoxicity against selected TNBC cell lines without affecting normal cells. In addition to the analysis of cellular apoptosis with mitochondrial membrane potential (Δψ_m) loss demonstrated an increased apoptotic cell death after 24 h at their dose-dependent concentrations. Thus we conclude that the synthesized AuNPs may directly inhibit the TNBC cell growth and induced the tumor cell autophagy which consequently increasing cellular apoptosis.