Journal of Nanomedicine & Nanotechnology

Abstract

Impact of Gold Nanoparticle Concentration on their Cellular Uptake by MC3T3-E1 Mouse Osteocytic Cells as Analyzed by Transmission Electron Microscopy

Thikra Mustafa, Fumiya Watanabe, William Monroe, Meena Mahmood, Yang Xu, Lamya Mohammed Saeed, Alokita Karmakar, Dan Casciano, Syed Ali and Alexandru S. Biris

The uptake mechanisms and kinetics of gold nanoparticles (AuNPs) by mouse calvaria osteoblastic cells have been studied by transmission electron microscopy (TEM). The average size of the as-synthesized AuNPs used in this study was 12.2 (± 1.3) nm, and they were used to expose MC3T3-E1 osteoblastic cells at two concentrations (10 and 160 μg/ml) for 6, 24, and 96 hours before TEM imaging. Based on this analysis, we propose that the uptake mechanism of AuNPs is concentration-dependent. At the higher concentration (160 μg/ml), the particles seem to penetrate inside the cells primarily by endocytosis as the cells engulf AuNPs as agglomerates formed on the outer cellular membrane. At the lower concentrations of 10 μg/ml, AuNPs are more likely to cross the plasma membrane individually through diffusion. Therefore, the average diameters of the nanoparticles are expected to have a significant role only when exposed to cells in low concentrations. Moreover, cytotoxicity assays showed no toxic effects of the AuNPs when MC3T3-E1 cells were exposed to concentrations used in the experiments.