An Advanced Fluorescent Molecularly Imprinted Sensor Based on Carbon Quantum Dots for Highly Sensitive Detection of 6-Mercaptopurine

This study developed a fluorescent molecularly imprinted sensor (CDs@MIPs) for the highly selective detection of the anticancer drug 6-mercaptopurine (6-MP). 6-MP is an anti-cancer drug with myelosuppressive and hepatotoxic effects. If used improperly, it can cause serious adverse reactions in humans and other organisms. The sensor was fabricated via the sol-gel method using blue-emissive nitrogen-doped carbon dots (CDs) as the fluorophore and 3-aminopropyl triethoxysilane (APTES) as the functional monomer. The sensor leveraged molecularly imprinted technology to construct specific recognition cavities, which enabled highly efficient and sensitive detection of 6-MP. Under the optimal experimental conditions and at 325 nm excitation, with the increase of 6-MP concentration, the fluorescence intensity of the sensor at the emission of 415 nm gradually decreases. The sensor demonstrated a linear detection range of 5.0-120.0 µM (Y = − 6.55X + 792.39) with a detection limit of 1.67 µM (S/ N  = 3). It exhibited strong anti-interference capability, excellent reproducibility and stable fluorescence performance. When applied to the detection of Mercaptopurine tablets, the method achieved recovery rate of 97.80%-108.63%, providing a highly sensitive and cost-effective analytical approach for clinical drug monitoring.