Chemical sensors for selective and quantitative heparin sensing
Heparin is widely used as an anticoagulant drug in clinics, especially in surgery and dialysis machines. For safe use of heparin, it requires that its dosage should be closely monitored during the application. However, this was determined to be a challenging task because the chemical stucture of heparin is very complicated. As a matter of fact, some well-established methods such as activated clotting time assay (ACT) or activated partial thromboplastin time assay (aPTT) were indirect and not accurate enough for monitoring heparin concentration. Therefore, the development of fluorescent sensors for selective, quantitative and fast heparin sensing has attracted much attention. Up to date, small organic molecule-based sensors, organic-inorganic hybrid materials and supramolecular complexes have been reported for heparin sensing. In this review, design strategy, working principle and sensing performance of chemical sensors for heparin were discussed in detail with representative examples that reported mainly within past 15 years (up to early 2020). These examples were summarized according to the type of their recognition units and the photophyscial sensing mechanisms.