Highly Sensitive Fluorescence Assay for Glucose Using Amine-Terminated Silicon Quantum Dots As a Non-enzymatic Bioprobe

Abstract

This work presents a simple, economic and green technique for functionalizing fluorescent silicon quantum dots (Si QDs) as a bioprobe to measure blood glucose levels. The functionalized Si QDs are synthesized by adding 3-aminopropyltriethoxysilane to a colloidal solution of Si QDs, freshly prepared by laser ablation of a silicon target in distilled water. The amine-terminated surface of Si QDs is confirmed using Fourier transform infrared spectroscopy, energy dispersive x-ray spectroscopy and UV–visible absorption spectroscopy. The photoluminescence of the colloid exhibits high photo-stability and good reproducibility making it a good candidate for fluorescent probes in biosensor studies. We have investigated the use of such functionalized Si QDs as a probe for fluorescent glucose detection application based on its effective fluorescence quenching by hydrogen peroxide, which is produced from glucose. The room temperature fluorescent glucose sensor, based on amine-functionalized Si QDs, gave a detection limit of 0.97 μM and a linear range from 20 to 700 μM. This non-enzymatic fluorescent biosensor system shows high sensitivity, excellent selectivity and extreme stability toward glucose.