A sensitive aptamer/protein binding-triggered sandwich assay for thrombin is described. It is based on electrochemical-chemical-chemical redox cycling using a glassy carbon electrode (GCE) that was modified with WSe 2 and gold nanoparticles (AuNPs). The AuNPs are linked to thrombin aptamer 1 via Au-S bonds. Thrombin is first captured by aptamer 1 and then sandwiched through the simultaneous interaction with AuNPs modified with thrombin-specific aptamer 2 and signalling probe. Subsequently, the DNA-linked AuNP hybrids result in the capture of streptavidin-conjugated alkaline phosphatase onto the modified GCE through the specific affinity reaction for further signal enhancement. As a result, a linear range of 0–1 ng mL −1 and a detection limit as low as 190 fg mL −1 are accomplished. The specificity for thrombin is excellent. Conceivably, this strategy can be easily expanded to other proteins by using the appropriate aptamer. [Figure not available: see fulltext.].
CITATION STYLE
Wang, Y. H., Xia, H., Huang, K. J., Wu, X., Ma, Y. Y., Deng, R., … Han, Z. W. (2018). Ultrasensitive determination of thrombin by using an electrode modified with WSe 2 and gold nanoparticles, aptamer-thrombin-aptamer sandwiching, redox cycling, and signal enhancement by alkaline phosphatase. Microchimica Acta, 185(11). https://doi.org/10.1007/s00604-018-3028-7
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