Ultrasensitive label-free homogeneous electrochemical aptasensor based on sandwich structure for thrombin detection

[Display omitted] •A novel homogeneous electrochemical aptasensor for thrombin detection.•The sensor is based on the sandwich structure with HAP NPs and magnetic beads.•The signal is amplified by using multiple nanomaterials.•The homogeneous sensor is more sensitive and accurate than heterogeneous o...

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Bibliographic Details
Published in:Sensors and actuators. B, Chemical Chemical, 2018-08, Vol.267, p.412-418
Main Authors: Zhang, Yaxing, Xia, Jianfei, Zhang, Feifei, Wang, Zonghua, Liu, Qingyun
Format: Article
Language:English
Subjects:
Biomarkers
Electrochemical aptasensor
Electrodes
Electron transfer
Homogeneous
Hydroxyapatite
Hydroxyapatite nanoparticles
Nanoparticles
Precipitates
Recognition
Sandwich structures
Sandwich-type
Sensors
Thrombin
Thromboembolism
Ultrasonic imaging
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Summary:[Display omitted] •A novel homogeneous electrochemical aptasensor for thrombin detection.•The sensor is based on the sandwich structure with HAP NPs and magnetic beads.•The signal is amplified by using multiple nanomaterials.•The homogeneous sensor is more sensitive and accurate than heterogeneous one. Herein, a sandwich-type homogeneous electrochemical aptasensor has been proposed for the determination of thrombin. The thrombin aptamer 1 modified magnetic nanoparticles (MNP-TBA1) are used as one recognition unit to bind the thrombin and the thrombin aptamer 2 modified hydroxyapatite nanoparticles (HAP-TBA2) are used as the other recognition unit for thrombin. When the thrombin exists, MNP-TBA1 is combined with HAP-TBA2 to form sandwich-type structure. In this protocol, HAP is also used as a signal probe, which can react with molybdate to produce redox-active molybdophosphate precipitates. In order to promote electron transfer and amplify signal, graphene is synthesized on the surface of electrode by one step. Compared with the traditional heterogeneous aptasensor, the homogeneous aptasensor can improve the target binding efficiency and avoid immobilizing biomolecule on the interface of electrode. Therefore, the homogeneous aptasensor presents a low detection limit of 0.03 fM for thrombin and a wide linear range (from 0.1 fM to 1.0 nM). Furthermore, the aptasensor exhibits a good selectivity and applicability in serum samples. More significantly, this homogeneous aptasensor gives inspiration to manufacture sensitive aptasensor for sensitive analysis of other biomarkers.
ISSN:0925-4005
1873-3077
DOI:10.1016/j.snb.2018.04.053