TPE-based cationic AIEgen with large stokes shift enables detection of blood anti-coagulator heparin with high selectivity.

In this present study, a thiazolium based tetraphenyl ethylene derivative (TPET) was developed for the sensitive and selective detection of heparin (Hp), exploiting the aggregation-induced emission (AIE) feature of TPE. The probe, TPET remains weakly emissive in its dispersed monomeric form but exhibits a pronounced fluorescence "turn-on" response upon interaction with Hp. The probe, TPET due to its inherent cationic nature, experiences a strong electrostatic interaction at the vicinity of polyanionic Hp, which eventually helps TPE derivative to form aggregated species, leading to fluorescence light up response via aggregation-induced emission (AIE). This strategy allows for reliable detection of Hp down to 20.2 nM in aqueous solution. Furthermore, ruggedness of the dye-Hp complex across a broad pH range, showcasing the excellent stability and environmental robustness of the TPE-based system. Importantly, the probe demonstrates excellent preferential response towards heparin compared to other glucosamines and bio-analytes, encouraging its utilization for Hp detection even in complex biomedia. The system achieved a low limit of detection (LOD) of 614.9 nM and 78.4 nM in 25% artificial urine and 0.5% human serum, respectively. Additionally, the dye-Hp complex can also be applied for the detection of Hp antidote, protamine (Pr) as low as 0.15 μM. Overall, this work demonstrates a promising, facile, and non-invasive method for Hp detection, which can be extended to biomedical and clinical diagnostics.