Label-Free Electrochemical Aptasensors

Li, B. L., Du, Y., Wei, H., Dong, S. J. (2007b). Reusable, label-free electrochemical aptasensor for sensitive detection of small molecules. Chem Commun 3780-3782. 

Here we describe two types of label-free electrochemical aptasensors for small molecule detection based on gold nanoparticle (AuNP) amplification (13,14). These sensors are designed with either signal-off or signal-on modes, respectively (see Fig. 1). 

As an example of application of electrochemical aptasensor to medical diagnosis. Sun et al. developed a label-free electrochemical aptasensor for thrombin detection in whole blood. For the fabrication of this aptamers, self-assembled multilayers of carboxymethyl-polyethylene glycol-carboxymethyl (CM-PEG-CM) and thrombinbinding aptamer (TBA) were used. The thrombin molecules in the medium bound onto the TBA which leads to current decrease. This current decrease was monitored by differential pulse voltammetry. A linear range of 1 pM to 160nM was obtained for thrombin with LOD value of 1.56 x (Sun et al., 2013). 

Sun, C., Wang, X., Yang, X., Xing, L., Zhao, B., Yang, X., Mao, C., 2013. A label-free electrochemical aptasensor for sensitive thrombin detection in whole blood. Electrochimica Acta 106, 327-332. 

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