Electron transfer aptasensor development

Electrochemical aptasensors have been developed widely for some period of time, especially in the most recent few years (Willner and Zayats, 2007). Due to the properties of the technique itself, most electrochemical aptasensors depend on electrodes for electron transfer. Thus, the SOALF mode could make sense. Here we introduce mainly easy routes in this mode rather than in the SFALF mode. 

Aptamer-based biosensors, also called aptasensor have gain a wide interest in the last years due to the advantages of aptamers compared to antibodies. Similar to antibodies, a variety of immobilization methods is available to bind aptamers to the sensor element. Aptasensors can be coupled to an electrochemical, optical or mass-sensitive transducer [13]. One of the successful examples for aptasensor was the detection of thrombin which was widely investigated [14]. Xiao et al. [15] have made an interesting development a redox compound (methylene blue) was inserted into the thrombin aptamer. When the target bound to the aptamer, the induced conformation change inhibited the electron transfer from the methylene blue to the electrode. This change could be detected amperometrically. 

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