Determination of glucose by using fluorescent silicon nanoparticles and an inner filter caused by peroxidase-induced oxidation of o-phenylenediamine by hydrogen peroxide.

The authors describe a new kind of enzymatic glucose assay. The strategy involves three processes: (a) Generation of HO via glucose oxidase catalyzed oxidation of glucose; (b) production of 2,3-diaminophenazine (DAP) from HO and o-phenylenediamine (OPD) via peroxidase-catalyzed oxidation; and (c) a reduction of the blue fluorescence of SiNPs with emission maxima at 445 nm via an inner filter effect that is caused by DAP which is yellow and has an absorption peak at 450 nm. Fluorescence drops with increasing glucose concentrations in the 0.01 to 7 mM concentration range, and the detection limit is 3.5 μM. The assay was successfully applied to the analysis of glucose in human serum. [ABSTRACT FROM AUTHOR]