Functionalized carbon dots of thiazole derivatives based on inner filter effect for tetracyclines detection

Abstract In this paper, we have developed a fluorescent probe based on thiazole derivative-functionalized carbon dots (CDs-AP) for the rapid, simple, and selective testing of commonly used antibiotics tetracyclines (TCs). Using citric acid (CA) and diethylenetriamine (DETA) as precursors, CDs rich in carboxyl groups were first synthesized, and then thiazole derivatives (AP) were covalently attached to the surface of CDs through an amidation coupling reaction. CDs-AP has high quantum yield (QY), excellent stability and good solubility. Response surface methodology (RSM) and the central composite design (CCD) were used to evaluate and optimize the operating parameters, including temperature, reaction time, and pH. Under the best operating conditions, CD-AP shows a good linear relationship for tetracycline (TET, an example for TCs), with a range of 0 – 18 μM and a detection limit of 0.7 nM. After detailed research, the inner filter effect (IFE) was proposed as the sensing mechanism. In addition, the probe has been successfully used for the determination of TET in milk samples and cell imaging for MDA-MB-231 cells.