Nanopipette Assisted Crystallization of Lipoic Acid

Nobel metal Au, Ag, Cu and Bi-metallic Nanoclusters (NCs), also known as monolayer protected clusters (MPAs), are a growing field in analytical chemistry and have applications as biosensors, catalysts, etc. It is postulated that the protective organic monolayer surrounding the metal core contributes to the physicochemical properties of the NCs. In this research, specific NCs ligands are evaluated for their propensity to spontaneously crystallize under an applied potential using a novel method established by our group called NanoAC or active control at the nanoscale. The ligands under investigation are lipoic acid (LA), mercaptosuccinic acid (MSH) and glutathione (GSH). Using a nanopipette under electrochemical application, LA has precipitated crystals outside the nanotip with a negative bias and with coprecipitant HCl. Future work will fine-tune the mole ratio of LA and HCl for crystal formation and correlate the results to crystal formation using MSH and GSH.