Recently the use of nanomaterials in industrial and technological applications for various fields is quickly growing. The "green" synthesis of metallic nanoparticles has received increasing attention due to the development of eco-friendly technologies. To date, most of the published preparation methods are based on using organic materials due to the hydrophobicity of the stabilizing agents used, such as natural polymers. In this study, silver nanoparticles have been successfully prepared through a simple and green method by reducing Ag+ ions in aqueous gelatin media at different concentrations. For this purpose, biological grade gelatin was used as a reducing and stabilizing agent without special physical conditions. The most advantage of this work is using a renewable material like gelatin, which are eco-friendly agent. The results illustrated that the size of obtained nano silver particles were in the range of nano from 8 to 25 nm. Silver nanoparticles were prepared in various gelatin concentrations such as 1,2 and 3 percent (GAl, GA2 and GA3 samples, respectively). the authors also investigated the cytotoxic effect of silver nanoparticles on HT29 colon cancer cell line and fibroblast cells isolated from peritoneum of BALB/c mice. Silver nanoparticles caused a dose dependent decreased of cell viability. Silver nanoparticles concentrations to induce 50 percent cell death (IC50) of GAl, GA2 and GA3 samples (silver nanoparticles were prepared by different gelatin concentrations: 1,2 and 3 percent) were 36,32
10,17 and 2,01 ppm, respectively on HT29 cell line but over 100 ppm while testing on fibroblast cells. The antibacterial activity of silver nanoparticles has been investigated as well. For all of the samples, the inhibition zones were larger than 6 mm in diameter. This suggested that all of the samples containing silver nanoparticles possess a significant antibacterial activity which is beneficial for many applications.