“In-vitro Safety Assessment of Ultrasmall Gold Nanoparticles for Preclinical Drug Delivery Applications”

Background: The development of safe and biocompatible nanoparticles has always been a major concern in nanomedicine applications. Various studies on the size-dependent toxicity of na-noparticles have been reported but are still controversial. The potential of small-sized nanoparticles can be utilized for imaging and diagnostics. However, insufficient toxicity data on these nanoparti-cles prevents researchers from utilizing their potential in diagnostics. More studies are needed on the toxicity of small-sized nanoparticles to present unanimous report for safe systemic use. The pre-sent study aimed to investigate the toxicity concerns of very small-sized AuNPs (2 ± 0.5 nm, 5 ± 1 nm, and 10 ± 2 nm) and provide a platform for their safe in vivo use. Methods: The cellular interactions of these three small-sized AuNPs with regard to cytotoxicity were investigated on hepatocellular carcinoma (HepG2) and epithelial kidney (HEK-293) cell lines. The cytotoxicity investigation of both cell lines was done through MTT assays, PI & DAPI, and cy-tology. Cellular stress was investigated by Catalase, TBARS, GSH, SOD & ROS parameters. The AuNPs incubated cells were also assessed for immunogenicity by ELISA, protein interaction by BSA, and cellular internalization by TEM (Edax). Result: All three-sized AuNPs were not toxic on cell viability, apoptosis, necrosis, or cytology as-sessment. No oxidative stress was noted in both cell types in the presence of 2 and 5-nm-sized AuNPs, whereas 10 nm-sized AuNPs showed little oxidative stress. AuNPs of size 2 and 5 nm were immunologically inert, but 10 nm-sized AuNPs elicited interleukin (IL-4 and IL-10) and interferon IFN gamma response. AuNPs of sized 2 nm showed 4 times the adsorption of albumin protein as compared to AuNPs of sized 5 nm. The TEM micrographs and peak of gold in the Edax graph con-firmed the presence of AuNPs in cells. Conclusion: Our results are suggestive of utilizing the potential of these three-sized AuNPs safely in preclinical drug delivery applications.