Highly sensitive fluorescence detection of heparin based on aggregation-induced emission of a tetraphenylethene derivative

Tetraphenylethene derivatives were reported for sensitive “turn on” detection of heparin (Hep) based on the typical aggregation-induced emission (AIE). In the present strategy, three derivatives of tetraphenylethene (TPE) were designed，synthesized and compared the sensitivities for the detection of Hep. Furthermore, the (Z)-4,4′-(((1,2-diphenylethene-1,2-diyl) bis(4,1-phenylene))bis (oxy))bis(butan-1-aminium) (Z-TPE-5) was the most sensitive and chosen as the probe for Hep detection. Since Hep could be employed as a medium for inducing the aggregation of positively charged Z-TPE-5, the designed Z-TPE-5 shows excellent fluorescence response to Hep through multiple electrostatic interactions with a detection limit of 1.53 ng/mL, which is far below than most of the reported method for the detection of Hep. Due to the stronger affinity between Hep and protamine, Hep preferred to bind with it instead of Z-TPE-5 after the addition of protamine, so the fluorescence could be reduced. In comparison to prior studies, this developed strategy here not only simplifies the preparation procedure of the fluorescent probes but also can be applied in sensitive determination of Hep with good accuracy. Moreover, the detection of Hep with Z-TPE-5 was not interfered by Hep analogues, such as chondroitin sulfate and hyaluronic acid, as well as in the matrix of human serum.