Cellular Uptake of Catharanthus roseus-Silver Nanoparticles in Human Hepatocellular Carcinoma HepG2 Cells

Abstract

Introduction: Nanoparticles exhibit unique features and currently at the forefront of cutting-edge research. Silver nanoparticles (AgNPs) are among the most promising and widely commercialised nanoproducts in various fields. The interaction of these AgNPs with cells remain unclear to connect with its toxicological endpoints. The aim of this study was to investigate the cellular uptake of C. roseus-AgNPs in hepatocellular carcinoma cells HepG2. Methods: The HepG2 cells were treated with the mean IC50 value of C. roseus-AgNPs which was 4.95±0.26 µg/mL for 24, 48 and 72 hours. The effects were compared with the untreated cells and other treatments which include camptothecin, C. roseus-aqueous extract, and AgNO3. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to quantify the intracellular Ag+ and Ca2+, while transmission electron microscopy (TEM) imaging was used to visualise the nanoparticle distribution. Results: The HepG2 cells have significantly taken up Ag+ from C. roseus-AgNPs with at least six times higher compared to Ag+ from AgNO3. The intracellular Ca2+ detected in HepG2 cells for all treatments were significantly higher than the untreated cells, in time-dependent manner. TEM images indicated the endocytosis of C. roseus-AgNPs with the presence of endosomes and exocytic vesicles. Conclusion: The significant accumulation of intracellular Ag+ demonstrated the efficiency of the C. roseus-AgNPs uptake while the increased Ca2+ indicated the early sign of cell injury. The cellular uptake was mainly through endocytosis. These findings are crucial to correlate the physicochemical properties of C. roseus-AgNPs with the anticancer mechanisms towards the development of liver cancer therapy.