Fluorescent and Colorimetric Dual-signal Enantiomers Recognition via Enzyme Catalysis: The Case of Glucose Enantiomers Using Nitrogen-doped Silicon Quantum Dots/Silver Probe Coupled with β-D-Glucose Oxidase.

Abstract

Chiral enantiomer recognition is important but facing tough challenges in the direct quantitative determination for complex samples. In this work, via chosing nitrogen-doped silicon quantum dots (N-SiQD) as optical nanoprobe and constructing N-SiQD/silver (N-SiQD/Ag NPs) complex, β-D-GOx as model enzyme and glucose enantiomers as analytes, a fluorescent and colorimetric dual-signal chiral sensing strategy was proposed herein for chiral recognition based on specific enzyme-catalyzed reaction. N-SiQD can exhibit intense fluorescence, while it can be quenched by Ag NPs owing to the formation of N-SiQD/Ag NPs. In the presence of glucose isomer, D-glucose is catalytically hydrolyzed by β-D-GOx to form H2O2 owing to the specific enzyme catalyzed reaction between D-glucose and β-D-GOx, and H2O2 can etch Ag NPs from the N-SiQD/Ag NPs probe to change the solution color from brown to colorless and restore the N-SiQD fluorescence; while these phenomena cannot be caused by L-glucose, a dual-signal sensing method was thus constructed for recognizing glucose enantiomers. It is believed that the chiral enantiomers recognition strategy via enzyme catalysis has great application for selective and quantificational detection of enantiomers in the complex sample system.