%0 Journal Article
%T Microscopic Studies of Various Sizes of Gold Nanoparticles and Their Cellular Localizations
%A Cemil Boyoglu
%A Qingwen He
%A Gerold Willing
%A Seyhan Boyoglu-Barnum
%A Vida A. Dennis
%A Shreekumar Pillai
%A Shree R. Singh
%J ISRN Nanotechnology
%D 2013
%R 10.1155/2013/123838
%X Gold nanoparticles (GNPs) are widely used in biological and clinical applications due to their favorable chemical and optical properties. GNPs can be used for drug delivery to targeted cells. In addition, GNPs serve as ideal probes for biological and cell imaging applications. Recent studies indicate that the size diversity of GNPs plays an important role in targeting cellular components for biomedical applications. In this study, we conducted a series of studies using different sizes of gold nanoparticles, including 3, 10, 25, and 50£¿nm, to determine the effect of size variations on their intracellular localizations. Our cytotoxicity studies of GNPs into the HEp-2 cells using MTT assay indicated that 3£¿nm GNPs possess the highest toxicity. We exposed HEp-2 cells with various sizes of gold nanoparticles for different time intervals (1, 2, 4, 12, and 24£¿h) followed by imaging using scanning electron microscope (SEM) and atomic force microscope (AFM). Our SEM and AFM results showed that, after 1£¿hr incubation, 3 and 10£¿nm gold nanoparticles entered the nucleus, whereas 25 and 50£¿nm particles accumulated around the nucleus. As the time of exposure increased, GNPs entered the cells and accumulated in the cytosol and nucleus based solely on their sizes. 1. Introduction Metal nanoparticles are currently used for a variety of biomedical applications [1¨C4]. The nanoscale size makes them comparable to the cellular components and proteins hence, nanoparticles can easily bypass natural barriers [5]. Metal nanoparticles exhibit remarkable optic, electronic, and chemical properties that can be tailored by size variations [6, 7]. Recent studies showed that the size diversity of nanoparticles plays a significant role in their extracellular and intracellular mechanisms [1, 8¨C10]. GNPs have been actively investigated in a wide variety of biomedical applications for several reasons; they have the advantage of small size, which is highly tunable (1¨C100£¿nm), they are capable of evading the immune system, and they are easily characterized by UV-Vis spectrometries and microscopies [11, 12]. The optical properties of GNPs, such as surface plasmon resonance, provide excellent florescence and photostability necessary for imaging applications [13, 14]. The chemical properties of GNPs, such as chemical inertness, low toxicity to human cells [15], and high selectivity [16], allow them to interact easily with biological systems. Recent studies of GNPs and their abilities to enter cellular compartments have opened doors for many other biomedical applications beyond GNPs as labels
%U http://www.hindawi.com/journals/isrn.nanotechnology/2013/123838/