Carbon dots coated with molecularly imprinted polymers: A facile bioprobe for fluorescent determination of caffeic acid.

A new and sensitive method for fluorescent determination of caffeic acid (CA) was proposed based on silane-functionazed carbon dots coated with molecularly imprinted polymers (CDs@MIPs). CDs@MIPs were prepared by using CA as the templates on the surface of silane-functionazed carbon dots(CDs) with a sol-gel process. The as-prepared CDs@MIPs were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and fluorescence spectroscopy. The CDs@MIPs exhibited distinguished selectivity and high binding affinity to CA templates, and also showed good reusability. Under optimal conditions, the fluorescence intensity of CDs@MIPs decreased linearly with the increase of CA in the range of 0.5-200 μM. The limit of detection was 0.11 μM (3σ/K). Finally, the proposed method was successfully applied to the detection of CA in human plasma. The result indicates that the method built has promising potential for monitoring CA concentration in clinic.