Nanotoxic Effects of Silver Nanoparticles on Normal HEK-293 Cells in Comparison to Cancerous HeLa Cell Line

Purpose: Biomimetic approaches for the synthesis of silver nanoparticles (AgNPs) had created a substantial impression among the research community that focuses on nano-bio interactions. In this study, an eco-friendly method using Rhizophora apiculata aqueous leaf extract as a reductant-rich hydrosol was followed to synthesize AgNPs and test its cytotoxicity. Methods: To optimise the parameters for the synthesis of AgNPs, central composite design based on response surface methodology was used. The particles synthesized at a nano-scale were characterized in our previously published report. The present report further characterizes the nanoparticles by X-ray diffraction, SEM and TEM at varying sites and magnifications. The characterized AgNPs were tested for their cytotoxic effects on HEK-293 and HeLa cells. Results: The cytotoxicity on the cell lines was dose-dependent. At a concentration of 2.5 mu L/mL of the AgNPs-containing hydrosol, 100% inhibition of HEK-293 cells and 75% inhibition of the HeLa cells were observed. The IC50 value for AgNPs on HEK-293 was 0.622 mu L/mL (12.135 ng), whereas, for HeLa cells, it was 1.98 mu L/mL (38.629 ng). Conclusion: The nanoparticles were three-fold toxic towards the HEK-293 cells in comparison to the HeLa cells. Therefore, the therapeutic index is low for R. apiculata derived AgNPs on HeLa cells when tested in comparison with the HEK-293 cells. The nanotoxicity profile of the synthesized AgNPs seems more prominent than the nanotherapeutic index. According to our knowledge, this is the first-ever report on the optimization of synthesis of AgNPs using response surface methodology and identifying the therapeutic index of mangrove leaf-derived AgNPs.

Automated summary

The biomimetic approach of synthesizing silver nanoparticles using Rhizophora apiculata leaf extract showed dose-dependent cytotoxic effects on HEK-293 and HeLa cells, being three times more toxic to HEK-293 cells compared to HeLa cells.