title: Analytical applications of enzymatic growth of quantum dots.
abstract: We have developed an analytical assay to detect the enzymatic activity of acetylcholine esterase and alkaline phosphatase based on the generation of quantum dots by enzymatic products. Acetylcholine esterase converts acetylthiocholine into thiocholine. The latter enhances the rate of decomposition of sodium thiosulfate into H(2)S, which in the presence of cadmium sulfate yields CdS quantum dots showing a time dependent exponential growth, typical of autocatalytic processes. This assay was also applied to detect acetylcholine esterase inhibitors. Alkaline phosphatase hydrolyzes thiophosphate and yields H(2)S, which instantly reacts with Cd(2+) to give CdS quantum dots. The formation of CdS quantum dots in both reactions was followed by fluorescence spectroscopy and showed dependence on the concentration of enzyme and substrate.
authors.affiliation: Biofunctional Nanomaterials, CIC biomaGUNE, Parque Tecnologico de San Sebastian, Paseo Miramon 182, 20009 San Sebastian, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Saa
authors.forename: Ana
authors.initials: A
authors.lastname: Virel
authors.forename: Jose
authors.initials: J
authors.lastname: Sanchez-Lopez
authors.forename: Valery
authors.initials: V
authors.lastname: Pavlov
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D055162:Biocatalysis; D019187:Cadmium Compounds / Q000737:chemistry; D006862:Hydrogen Sulfide / Q000378:metabolism; D045663:Quantum Dots; D013431:Sulfates / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D013431:Sulfates; C037123:cadmium sulfate; D000110:Acetylcholinesterase; D000469:Alkaline Phosphatase; D006862:Hydrogen Sulfide