High-sensitivity detection for cantharidin by ratiometric fluorescent sensor based on molecularly imprinted nanoparticles of quantum dots

Cantharidin (CTD), an effective component of Chinese herbal medicine with unique efficacy, caused poisoning or death constantly for incorrect use. Therefore, there is an intense need for a reliable, selective, sensitive and low-costing analytical method for monitoring the concentration of CTD in biological samples. In this work, a ratiometric fluorescent sensor (CdTe@MIPs/CDs@NIPs) was successfully constructed for selective determination of CTD by simply integrated the non-imprinted polymers coated CDs (CDs@NIPs) with cadmium telluride quantum dots coated with molecular imprinted polymers (CdTe@MIPs). CDs@NIPs were directly used as reference signal without addition of CTD templates and the as-prepared CdTe@MIPs were response signal. With the CTD addition, the fluorescence intensity of CdTe@MIPs decreased, while the fluorescence of CDs@NIPs remained approximately unchanged, resulting a detection limit as low as 0.15 nM. By spiked human blood samples, the ratiometric sensor was successfully applied to CTD detection with good recoveries of 96.12–107.40% and relative standard deviation (RSD) of 2.87–3.96%. Moreover, after centrifuging and re-eluting, the developed sensor could be effectively recycled and reused five times. Significantly, the proposed platform with low-cost and high-sensitivity opens a door towards the practical applications of ratiometric sensor and shows immense potential in pursuing the sensitive, reliable and low-cost determination of poisons in forensic toxicology analysis.