Analytical applications of enzymatic growth of quantum dots.
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.
Saa
Laura
L
Biofunctional Nanomaterials, CIC biomaGUNE, Parque Tecnologico de San Sebastian, Paseo Miramon 182, 20009 San Sebastian, Spain.
Virel
Ana
A
Sanchez-Lopez
Jose
J
Pavlov
Valery
V
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
D019187:Cadmium Compounds; D013431:Sulfates; C037123:cadmium sulfate; D000110:Acetylcholinesterase; D000469:Alkaline Phosphatase; D006862:Hydrogen Sulfide