A Facile Room Temperature Synthesis of Large Silver Nanoplates with Low Cytotoxicity

In this work, a simple, fast, and room temperature aqueous-phase route was developed to synthesize highly aniotropic silver (Ag) nanoplates with controllable sizes from 1 to 17 mu m. Our simple synthetic protocol involves the direct reduction of polyethyleneimine (PEI) stabilized silver chloride (AgCl) nanoparticles with hydrogen peroxide (H2O2) in the presence of pyrrolidone in an aqueous-phase at room temperature for short reaction time of 10min. In the growth mechanism study, we found that the AgCl nanoparticles (seeds) were formed by the precipitation reaction of AgNO3 with NaCl in the presence of PEI at the early stage, and after the addition of H2O2, Ag+ in AgCl was reduced to Ag-0, making small Ag nanoparticles. Then large Ag nanoplates were formed by attachment and fusion of the small Ag nanoparticles. Cytotoxicity of Ag nanoplates was tested with by human adipose derived stem cells. Ag nanoplates showed no cytotoxicity upto 50 mu M/ml while 5 mu M/ml of Ag nanoparticles treatment showed high cytotoxicity. Also Ag nanoplates treated cells showed reduced pro-apoptotic gene expressions copampared to Ag nanoplates treatment. This modality may lead to further bio-application based on Ag nanoplates.