Sensors Based On Noble Metal Nanoculsters

Noble metal nanocluster(NCs), such as gold and silver ones, are a type of useful nanomaterials. In recent years, highly luminescence and stable NCs are intensively reported as fluorescence probes for a wide range of targets. Most of these detections are based on either the enhancement or the queching of the fluorescence. In this paper, based on the fluorescence quenching from targets, we developed a variety of sensing systems.In the first part, we synthesised silver nanoclusters stabibized by bovine serum albumin, and we studied the response of silver nanocluster fluorescent probe toward metal ions, developed a method to detect Cu2＋through fluorescence quenching. Furtherly, the complexation of histidine toward copper ion was adopted for an indirect detection of histidine.In the second part, we developed a method that improved the selectivity of gold nanoclusters toward copper and mercury ions. Bovine serum albumin stabilized gold nanocluster responded to both these two ions through fluorescence quenching. EDTA and sodium borohydride were added respectively as the "masking" reagents, in which EDTA complexed with Cu2＋, and borohydride reduced Hg2＋into HgO. Both these reactions inhibited the ions’interaction with the nanocluster and eliminated related quenching effect, thus detection of the other ion was achieved. Good selectivity of the nanocluster over these two ions was obtained enabling sensitive detection even under their coexistence.