A fluorescence turn-on biosensor utilizing silicon-containing nanoparticles: Ultra-sensitive sensing for α-glucosidase activity and screening for its potential inhibitors.

A facile and sensitive method for sensing α-glucosidase (α-glu) and screening its inhibitors based on fluorescence monitoring of water-solute silicon-containing nanoparticles (Si CNPs) was proposed and demonstrated. Such fluorescent nanoparticles can be easily produced by mixing (3-aminopropyl) trimethoxysilane (APTMS) and ascorbate sodium (AS) (both without fluorescence signals) at room temperature and pressure. If the ascorbate sodium was replaced by L-ascorbic acid-2-O-α-D-glucopyranosyl (AA2G), which can be hydrolyzed into the former by α-glu, the fluorescence "turn-on" biosensor for α-glu activity can be established. The sensing platform showegd a linear relationship from 10 to 140 U/L and a low detection limit of 0.42 U/L, which is superior to most approaches that have been reported. However, the hydrolysis procedure and subsequent fluorogenic reaction could be blocked in the presence of α-glu inhibitors (AGIs), giving the possibilities of screening various inhibitors from different compounds. Furthermore, detection in human serum and applications in AGIs screening by using this method were also constructed, and showed satisfying results as well. It is proved that this developed biosensor can provide an alternative strategy for potential clinic diagnosis and medicine development.