Benzothiazole derivative-functionalized carbon dots for the detection of berberine hydrochloride

Abstract

Berberine hydrochloride (BRH) has a wide range of biomedical values, including antioxidant, antibacterial and anti-cancer, so it is very important to establish a rapid and effective method for the determination of BRH. Herein, the fluorescent CDs with rich carboxyl groups on the surface were synthesized by the facile one-pot hydrothermal treatment of citric acid and methionine. The surface of CDs was further modified with 2-(4-aminophenyl)benzothiazole (ABT) to obtain CDs-ABT. The emission generated by the surface energy trap becomes more stable after surface modification, so CDs-ABT (31%) has a larger quantum yield than CDs (25%). In addition, BRH can significantly quench the fluorescence of CDs-ABT through inner filter effect (IFE). Experiments were carried out by using central composite design (CCD) and response surface method (RSM) and the best conditions for detecting BRH were obtained. Excellent linear correlation between the BRH concentration in the range of 10–130 μM and the fluorescence quenching of CDs-ABT was observed, and the limit of detection down to 3.5 nM. The assay was successfully applied to the detection of BRH in actual drug samples.