A tetracationic aggregation induced emission-based probe for efficient and improved detection of Heparin

Designing efficient fluorescent probes with Aggregation Induced Emission (AIE) feature, especially for sensing biologically important analytes, is an intensive area of investigation. Heparin is a well-known blood anticoagulant, and is routinely used as a very important medication in clinical setups. In this contribution, we have utilized a tetraphenylethylene derived AIEgen, named tetrapyridinium-tetraphenylethylene (TPy-TPE), for sensing Heparin. TPy-TPE carries four positive charges and forms aggregates in presence of negatively charged Heparin to generate highly emissive aggregates of TPy-TPE. Most importantly, the tetracationic nature of TPy-TPE provides a stronger binding affinity towards Heparin compared to the previously reported monocationic or dicationic fluorophores. The improved interaction between Heparin and TPy-TPE has proved to be advantageous in terms of improved sensitivity (lower LODs in aqueous and serum samples), higher fluorescence enhancement and better performance in complex matrices. While TPy-TPE is utilized for Heparin determination, its sole U.S. Food and Drug Administration (FDA) authorized antidote, Protamine, and Heparinase, which specifically degrades Heparin to produce clinically important Low Molecular Weight Heparin (LMWH) have also been detected through TPy-TPE molecule. Overall, the photophysical investigation of TPy-TPE for the detection of Heparin is a successful attempt and is expected to enhance Heparin related biosensing research in the biomedical fields.