Fluorescent Ag Clusters via a Protein-Directed Approach as a Hg(II) Ion Sensor

Proteins have proven to be particularly attractive as effective ligands in the synthesis of nano and subnanoscaled materials because of their multiple chelating and functional groups imparting unique functionalities. However, protein-directed fluorescent metal cluster synthesis is still a challenge but a promising. area of research. Here, we report on the synthesis of new Water-soluble, stable, fluorescent Ag clusters via a facile, green method using denatured bovine serum albumin (dBSA) as a stabilizing agent. The dBSA with its 35 free cysteine residues Could contribute to polyvalent interactions with the Ag clusters and serve as effective stabilizing agents for these clusters. The as-prepared Ag clusters showed high fluorescence emission at similar to 637 nm and were stable even in 1 M NaCl. The fluorescent Ag clusters were then used in the detection of Hg(2+) with high sensitivity and selectivity. The detection limit was 10 nM in the linear range from 10 nM to 5 mu M.