Application of a Near-Infrared Fluorescence Probe Based on Perylene Bisimide in the Detection of Heparin

Heparin is widely used to treat thrombosis because it is an effective anticoagulant. However, excessive use of heparin can lead to an increased risk of bleeding, which makes the quantitative detection of heparin very important. An amphiphilic perylene bisimide molecule (denoted PBI-9) was developed, which presented a near-infrared emission peak at 730 nm when it was aggregated. PBI-9 has been utilized in the detection of heparin, as the pyridine cation in PBI-9 binds strongly to highly sulfated heparin through electrostatic interactions. Charge neutralization triggers the self-assembly of PBI-9, which leads to an emission peak shift from 540 nm to 690 nm, corresponding to monomeric emission to excimer emission. This shift was applied for the detection of heparin. Importantly, the interaction between PBI-9 and heparin is not affected by protamine, resulting in high selectivity and minimal interference. PBI-9 is a promising tool for detecting heparin in clinical settings after excess heparin has been neutralized by protamine.