In Vitro Tracking of the Gold Nanoparticles

Abstract

Gold nanoparticles are nanomaterials with desirable properties, such as ease of preparation and bioconjugation, efficient resistance to surface oxidation and unique optical properties. These properties make them ideal probes for biological and cell imaging applications. In this study, we conducted a series of studies using different sizes of gold nanoparticles, including 3.5nm, 10 nm, 26nm and 50 nm, to determine if the size of the nanoparticle affects cell entry. We also tracked the movement of the gold nanoparticles with different microscopic techniques, such as Confocal Laser Microscope, Atomic Force Microscobe, Scanning Electron Microscobe and Transmission Electron Microscobe. We used HEp-2 cell lines and stained the nucleus, mitochondria, golgi apparatus, and plasma membrane using different stains to track the gold nanoparticles movement in the cell. We found that gold nanoparticles exhibited different behaviors depending on their sizes, and are located in different organelles during different times (1h, 2h, 4h, 8h, 12h, 24h, 48h, and 72h). Our confocal study results showed that as the size of the gold nanoparticles increases, the time of entering the cells was delayed. We also observed that nanaparticles occupied different organelles as time incubation periods increased. For example, 3.5nm gold nanoparticles accumulated on the plasma membrane after 1 h of incubation, then moved to the mitochondria after 4h of incubation and then to the nucleus after 24 h of incubation. In contrast, 10nm gold nanoparticles were not near the plasma membrane even after 2h incubation and were primarily in the mitochondria after 24 h of incubation.