Dual Role of a Fluorescent Peptidyl Probe Based on Self-Assembly for the Detection of Heparin and for the Inhibition of the Heparin-Digestive Enzyme Reaction.

The detection of fluorescent probes for biomolecules and control of the function of a complex through a recognition process have not been investigated intensively. A fluorescent peptidyl probe (1) based on the self-assembly stimulated by heparin was synthesized. The fluorescent probe with an aggregation-induced emission fluorophore formed a self-assembling complex with heparin, resulting in a sensitive and selective turn-on response to heparin compared to its biological competitors. The detection limits for heparin were measured to be 138.0 pM (R2 = 0.976) in aqueous solution and 2.6 nM (R2 = 0.996) in aqueous solution containing human serum. Nanosized aggregates formed through the self-assembly of the complex showed potent resistance against the heparin-digestive enzyme. The dual role of the probe for the detection of heparin and the inhibition of heparinase-mediated digestion through the recognition process was used for the real-time monitoring of the enzyme activity of heparinase for the digestion of heparin. Furthermore, the dual role of the probe was applied for the detection of the oversulfated chondroitin sulfate contaminant in heparin.