Studies on assessment of biocompatibility of Gold and Silver nanoparticles in cell culture for tissue engineering applications

Abstract

The present work involves studies on assessment of biocompatibility of gold and silver nanoparticles in cell culture for tissue engineering applications. As the field of Nanotechnology continues to develop, the studies on the cellular uptake of nanoparticles, with respect to their size and shape, are required in order to advance nanotechnology for biomedical applications. The toxicity of nanoparticles inside the biological system has always been an issue of concern. We specifically selected gold and silver nanoparticles because of their well-known applications in traditional Ayurvedic & Unani medicine, amenability of synthesizing these nanoparticles of various sizes and shapes, easy characterization by UV-Vis spectrophotometry and Transmission Electron Microscopy (TEM). Furthermore, the reports on gold nanoparticles for cell imaging, targeted drug delivery, cancer diagnostics and therapeutic applications indicate their potential in biology and medicine. During the study dose and time dependent nanoparticle cytotoxicity was assessed on different types of cells including fibroblasts, epithelial, endothelial, macrophages, and cancerous cells. To examine the effect of gold nanoparticles on cell proliferation, metabolism and cell viability; trypan blue dye exclusion test and 3- (4,5-dimethylazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay were performed. Our results indicate that Au(0) nanoparticles do not show detectable cytotoxicity upto 200 μM concentration of gold for 72 h exposure. Reactive oxygen species (ROS) and nitrite species (RNS) play an important role in toxicity. Hence, in response to gold nanoparticles, release of ROS and RNS species in a dose and time dependent manner was studied in RAW264.7 macrophage cells. We found no change in the levels as compare to untreated cells. There was no induction in the stress induced cytokines viz. TNF and IL-1 beta levels in response to increasing concentration of gold nanoparticles at transcriptional as well as protein level. We also didn’t observe any change in total protein profile of the cells treated with nanoparticles. Further, the gold nanoparticles do not affect the cellular cytoskeletal organization even at higher concentration and longer exposure.