Aggregation-Induced Emission Enhancement of CdSe QDs by Protamine and its Application to Sensitively and Selectively Detect Heparin

Background: Heparin, it is commercially used as an anticoagulant in surgical procedures for the prevention of blood clotting. However, overdose and prolonged use of heparin often induce potentially fatal bleeding complication. So, it is of crucial importance to monitor closely heparin levels for the sake of health. In this work, a sensitive fluorescence sensing platform to detect heparin was set up based on MPA-CdSe QDs (quantum dots) and protamine enhanced fluorescent system. Methods: The image of CdSe QDs was taken on a JEM-2100 transmission electron microscope (JEOL Ltd.). The fluorescence spectrum was recorded on a FluoroMax-4 fluorescence spectrophotometer (Horiba, USA). UV-vis absorption spectrum was recorded using a Shimadzu UV-2450 Spectrophotometer (Tokyo, Japan). A vortex mixer IKA MS3 digital was selected to mix the solution. Results: Under optimized conditions, the linear response to detect heparin ranges from 0.06 to 14 mu g mL(-1) with a detection limit of 8 ng mL(-1). The approach showed a highly selective response to heparin in the presence of 16 interfered substances. Conclusion: A simple method for the detection of heparin was developed based on MPA-CdSe QDs and protamine enhanced fluorescent system. The electrostatic effect between MPA-CdSe QDs and protamine resulted in strong fluorescence enhancement from the MPA-CdSe QDs. Moreover, the addition of heparin could cause a significant fluorescence decrease due to the strong affinity of protamine and heparin. Under optimal conditions, this method displayed a low detection limit and good selectivity over other substances.