Skip to main content
. Author manuscript; available in PMC: 2010 Apr 30.
Published in final edited form as: Proc SPIE Int Soc Opt Eng. 2009;7321:732105. doi: 10.1117/12.820419

Fig. 1.

Fig. 1

The electrochemical aptamer-based sensor consists of an electrode-bound DNA strand that is modified with a redox active probe (MB). The rearrangement of the aptamer structure brings the redox tag in close proximity of the electrode thus resulting in increased faradaic current. Shown are (top) the original 32-base cocaine aptamer sequence and two alternative structures that, in an effort to reduce background currents and increase the sensor’s gain, we have characterized here: (bottom left) the 96-base concatenated cocaine concaptamer – three cocaine aptamer sequences concatenated into a single poly-aptamer, and (bottom right) the 92-base pseudosandwich construct which is the single aptamer split into two pieces linked via an unstructured, 60-thymine sequence.