title: An aptamer-based single particle method for sensitive detection of thrombin using fluorescent quantum dots as labeling probes.
abstract: In this study, an aptamer-based single particle method was developed for the thrombin detection in human serum samples using fluorescence correlation spectroscopy (FCS). In this method, quantum dots (QDs) were used as the fluorescent probes and thrombin-binding aptamer (TBA) was used as molecular recognition unit. When two QDs probes labeled with TBA (QD-TBA1 and QD-TBA2) are mixed in a sample containing thrombin targets, the binding of targets will cause QDs to form dimers (or oligomers) with bigger sizes, which leads to the nearly double increase in the characteristic diffusion time of QDs in the detection volume of FCS. FCS method can detect the change in the characteristic diffusion time of QDs. Firstly, the diffusion and blinking behaviors of QD-TBA probes in the presence of thrombin were investigated by FCS and total internal reflection fluorescence microscopy (TIRFM) imaging system, and the experimental results documented that QD-TBAs were bound together with "one-by-one" structure when thrombin were added into the solution. And then, the assay conditions were optimized in order to improve the sensitivity and specificity of this method. Under the optimized conditions, the linear range of the method is from 5.0 nM to 500 nM of thrombin, and the limit of detection is about 2.6 nM. Finally, this method was applied to homogeneous determination of thrombin in human serum samples.
authors.affiliation: School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China.
authors.forename: Jinjin
authors.initials: J
authors.lastname: Yin
authors.affiliation: School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China.
authors.forename: Aidi
authors.initials: A
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China.
authors.forename: Chaoqing
authors.initials: C
authors.lastname: Dong
authors.affiliation: School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China. Electronic address: jicunren@sjtu.edu.cn.
authors.forename: Jicun
authors.initials: J
authors.lastname: Ren
mesh_terms: D052157:Aptamers, Nucleotide / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D001774:Blood Chemical Analysis; D019281:Dimerization; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013917:Thrombin / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D005456:Fluorescent Dyes; C081676:thrombin aptamer; D013917:Thrombin
keywords: Aptamer; Fluorescence correlation spectroscopy (FCS); Homogeneous determination; Quantum dots (QDs); Thrombin