A real-time and highly sensitive fiber optic biosensor based on the carbon quantum dots for nitric oxide detection

Abstract

Nitric oxide (NO) is a signal molecule with a wide range of functions and unique properties in organisms. A novel fluorescent probe composed of carbon quantum dots (CQDs) with o-phenylenediamine groups was prepared by the microwave method to detect NO selectively. The mechanism of the reaction between CQDs and NO was established by a series of characterization methods, such as fluorescence spectrophotometer, UV–vis absorption spectrophotometer and transmission electron microscope. The result showed that the o-phenylenediamine groups on the surface of the CQDs can react with NO to form an electron-free triazole structure, leading to the decrease of fluorescence of the CQDs. Furthermore, a new optical fiber sensing system based on the CQDs was constructed to detect NO with a low detection limit of 9.12 nM at laser power of 280 mW. In addition, the NO optic fiber biosensor also was used to detect NO concentration in real human serum samples.