Authors: C. Boyoglu, S. Boyoglu-Barnum, S. Soni, Q. He, G. Willing, M.E. Miller, S.R. Singh
Affilation: Alabama State University, United States
Pages: 489 - 492
Keywords: HEp-2 cells, gold nanoparticle, in vitro
Gold nanoparticles (GNPs) are widely used in biological and clinical applications due to their favorable optical and chemical properties. The scientific understanding of the intracellular uptake of GNP is required for biomedical applications, such as drug delivery and therapeutic applications. In this study, we conducted a series of studies using different sizes of gold nanoparticles (3.5 nm, 10 nm, 26 nm and 50 nm) to determine the effect of nanoparticle size on the intracellular localization of GNPs. We infected HEp-2 cells with different size of gold nanoparticles and incubated at 1h, 2h, 4h, 12h, 24h, and 48h time intervals followed by imaging using different microscopic techniques, such as scanning electron microscope (SEM), atomic force microscope (AFM), and confocal microscope. In our confocal study, we stained the nucleus, mitochondria, and plasma membrane using different stains, and also we took the advantages of quantum dots to label microtubules, golgi apparatus, and lysosomes. Our SEM and AFM results showed that after 1 h incubation, 3.5, 10 and 26 nm gold nanoparticles entered nucleus, whereas 50 nm particles accumulated around nucleus. According to confocal images, single GNP emitted blue color, whereas aggregation leads to emission in red color range. Our results confirm previous studies that small nanoparticles emit energy with small wavelength, whereas bigger particles release energy with larger wavelength. As GNPs enter the cells, they accumulated in nucleus, resulting in emission of energy with larger wavelength. Thus, we observed aggregated gold nanoparticles in nucleus with red fluorescence.