Molecularly imprinted polymer-modified carbon dots as a fluorescent probe for caffeic acid detection

Caffeic acid is a phenolic acid compound widely present in nature. While beneficial to human health within a certain concentration range, excessive intake may lead to a series of health issues, such as liver and kidney function impairment. Therefore, developing a method for the precise and rapid detection of caffeic acid concentration in serum is of great significance for guiding rational clinical medication, drug monitoring, and daily health management. This study prepared a molecularly imprinted polymer (MIP) fluorescent probe for caffeic acid detection. Blue fluorescent carbon dots (bCDs) were synthesized via a one-step hydrothermal method using citric acid and diethylenetriamine as precursors. Subsequently, a molecularly imprinted silica shell was constructed on the bCDs' surface via a sol-gel method to obtain the bCDs@MIP fluorescent probe. Leveraging the specifically tailored recognition cavities created by molecular imprinting technology, the probe selectively captures caffeic acid, leading to fluorescence quenching. The degree of fluorescence intensity reduction exhibits a positive correlation with caffeic acid concentration, enabling its quantitative detection. The limit of detection (LOD) for caffeic acid was 0.15 µM. The probe was successfully applied to the determination of caffeic acid in human serum, providing a promising fluorescent strategy for caffeic acid analysis.