title: Bimodal quantitative monitoring for enzymatic activity with simultaneous signal increases in 19F NMR and fluorescence using silica nanoparticle-based molecular probes.
abstract: We describe the bimodal quantitative assay for enzymatic activity in (19)F NMR spectroscopy and fluorescence spectroscopy using a nanoparticle-based molecular probe. Perfluorinated dendrimers were tethered on silica nanoparticles with a phosphate-caged fluorescein as a linker. Before enzymatic reaction, the molecular rotation of the perfluorinated dendrimers should be highly restricted, and the (19)F NMR signals from the perfluorinated dendrimers were too broad to be detected relative to the noise level. Fluorescence signals of fluorescein were suppressed by the presence of the diphosphate groups. Following the enzymatic reaction with an alkaline phosphatase, perfluorinated dendrimers and fluorescein were released, and the NMR signals of perfluorinated dendrimers and strong fluorescence from fluorescein were correspondingly observed. The enzymatic activity and reaction rates of the hydrolysis of alkaline phosphatase were detected from the increases of fluorescence and (19)F NMR signals. Finally, the feasibility of the probe in the presence of miscellaneous molecules under biomimetic conditions was demonstrated by determining of the enzymatic activity in cell lysate. Quantitative analysis using both (19)F NMR spectroscopy and fluorescence spectroscopy can be accomplished.
authors: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors: Kazuo
authors: K
authors: Tanaka
authors: Narufumi
authors: N
authors: Kitamura
authors: Yoshiki
authors: Y
authors: Chujo
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D050091:Dendrimers; D004798:Enzymes / Q000378:metabolism*; D019793:Fluorescein; D005461:Fluorine; D009682:Magnetic Resonance Spectroscopy; D015336:Molecular Probe Techniques; D015335:Molecular Probes; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide; D013050:Spectrometry, Fluorescence
chemical_list: D050091:Dendrimers; D004798:Enzymes; D015335:Molecular Probes; D005461:Fluorine; D012822:Silicon Dioxide; D000469:Alkaline Phosphatase; D019793:Fluorescein