Abstract
Carboxyl-functionalized semiconducting polymer dots (Pdots) were synthesized as an energy donor by the nanoprecipitation method. A black hole quenching dye (BHQ-labelled thrombin aptamers) was used as the energy acceptor, and fluorescence resonance energy transfer between the aptamers and Pdots was used for fluorescence quenching of the Pdots. The addition of thrombin restored the fluorescence intensity. Under the optimized experimental conditions, the fluorescence of the system was restored to the maximum when the concentration of thrombin reached 130 nM, with a linear range of 0–50 nM (R2 = 0.990) and a detection limit of 0.33 nM. This sensor was less disturbed by impurities, showing good specificity and signal response to thrombin, with good application in actual samples. The detection of human serum showed good linearity in the range of 0–30 nM (R2 = 0.997), with a detection limit of 0.56 nM and a recovery rate of 96.2–104.1%, indicating that this fluorescence sensor can be used for the detection of thrombin content in human serum.
Highlights
As an important physiological protease, thrombin is involved in many physiological and pathological activities, such as blood coagulation, thrombosis and haemostasis [1,2]
The binding between target molecules of nucleic acid aptamers and proteins selected using the technique of systematic evolution of ligands by exponential enrichment (SELEX) is similar to the binding of antibody and antigen
Nucleic acid aptamers can tightly bind to the target molecule, showing advantages of good storage attribute, high specificity, strong affinity, and high selectivity, and have been widely applied in studies to identify the aptamer sensor of different disease-related protein molecules [6,7,8,9,10,11]
Summary
As an important physiological protease, thrombin is involved in many physiological and pathological activities, such as blood coagulation, thrombosis and haemostasis [1,2]. Nucleic acid aptamers can tightly bind to the target molecule, showing advantages of good storage attribute, high specificity, strong affinity, and high selectivity, and have been widely applied in studies to identify the aptamer sensor of different disease-related protein molecules [6,7,8,9,10,11]. Kopelman’s group recently reported a new method for the detection of thrombin by magnetic bead rotation [25]. The research group of Gao reported a new thrombin detection method based on a phosphorescence energy transfer system with a detection limit of 0.013 nM [26]. Pdots have excellent optical properties, asabsorption a large optical section and cross high fluorescence quantum yield, and show good colloidal stability.
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