title: Protein-gold nanoclusters for identification of amino acids by metal ions modulated ratiometric fluorescence.
abstract: Here we report that the dual fluorescence emissions from protein-gold (Au) nanoclusters can greatly be modulated by metal ions and the resultant fluorescence ratiometric responses provide a novel sensory method for the identification of amino acids. The protein-gold (Au) nanoclusters were simply synthesized by the reduction of chloroauric acid with bovine serum albumin (BSA), which exhibit dual emissions: the blue at 425 nm from the oxides of BSA, and the red at 635 nm from Au nanoclusters. It has been demonstrated that different metal ions react with BSA-Au nanoclusters and thus greatly affect the two emissions in different ways by fluorescence enhancement or quenching. Interestingly, the addition of amino acids leads to fluorescence ratiometric changes through the interactions with the bound metal ions. When BSA-Au nanocluster probes modulated by four different metal ions were used together to construct a sensor array, different amino acids were clearly discriminated by the distinctive patterns of four ratiometric fluorescence responses. Results and methods reported here provide a unique strategy for the determination of amino acids.
authors.affiliation: Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Qingsong
authors.initials: Q
authors.lastname: Mei
authors.forename: Kui
authors.initials: K
authors.lastname: Zhang
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D000818:Animals; D002417:Cattle; D002623:Chemistry Techniques, Analytical; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D000596:Amino Acids; D005456:Fluorescent Dyes; D012710:Serum Albumin, Bovine; D006046:Gold