Analytical Sciences

Improvement of Electrochemical Response of Cocaine Sensors Based on DNA Aptamer by Heat Treatment

Satoshi ARIMOTO,* Ken SHIMONO,* Tomoyuki YASUKAWA,** Fumio MIZUTANI,** and Toshihiko YOSHIOKA*

*Advanced Research Division, Bio Research Department, Panasonic Corporation, 3-4 Hikaridai, Seika, Soraku, Kyoto 619-0237, Japan
**Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan

We report on a biosensor for cocaine based on the conformation change of DNA aptamer by capturing the cocaine molecules. The oxidation current of ferrocene conjugated on the terminal end of aptamer immobilized on an Au electrode increased with increasing cocaine concentration. The sensor response has been improved by a simple heat treatment after immobilization, since the aggregates of DNA aptamer generated during the immobilization step could be dissociated and rearranged on the electrode.

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