GREEN ROUTE TO PREPARE BIOCOMPATIBLE AND NEAR INFRARED THIOLATE-PROTECTED COPPER NANOCLUSTERS FOR CELLULAR IMAGING

Ultra-small and functional copper nanoclusters (Cu NCs) have been extensively used in consumer technologies due to their superior properties. A simple and green way to prepare stable, water-soluble and near-infrared (NIR) Cu NCs by using a reducing agent was reported in this work. Reduced glutathione (GSH) worked as an important scaffold to prevent NCs from aggregating. Since GSH has functional groups such as carboxyl and amino, it can also be used in reducing Cu 2+ ions. The resulting GSH– Cu NCs with a particle size of 2.5 nm have good dispersibility in aqueous solution, and show NIR emission with a wavelength of 700 nm (quantum yield 0.6%). MC3T3-E1 cells are used as an example in the fluorescence imaging of GSH– Cu NCs. Several promising features including NIR fluorescence, good water-solubility and biocompatibility, bioactive surface and ultra-small size make the GSH– Cu NCs a good probe for cells.