A near-infrared fluorescent probe with AIE properties for rapid detection of Heparin

Heparin is a common blood anticoagulant, and is widely used in biomedical fields. Herein, we design a readily effective fluorescent probe for the detection and quantitation of Heparin. A nonemissive quinoline-malononitrile derivative QM-CO is affected to emit by Heparin, showing a near-infrared aggregation-induced emission (AIE), which produces the AIE effect more 4.62-fold fluorescence emission intensity than free QM-CO. The AIE probe enjoys a good linear relationship with the Heparin concentration is in the range of 0-1.75 & mu;g/mL (R2 = 0.9937), a low detection limit (down to 0.139 & mu;g/mL), and a superior selectivity to correlative substances. Utilizing the AIE feature of QM-CO and the electrostatic adsorption from Heparin to QM-CO, the AIE-based near infrared fluorescent probe QM-CO achieved a long wavelength (665 nm) emission and good selectivity for Heparin. Scanning electron microscopy (SEM) suggests that the loose aggregate QM-CO ensembles are disassembled and respectively condensed to form many tightly packed QM-CO/Heparin ensembles, offering mechanistic insight into the microenvironment of QM-CO/Heparin ensembles with the aid of the zeta potential.