Analytical Sciences

Abstract − Analytical Sciences, 19(5), 653 (2003).

Sensing Phenothiazine Drugs at a Gold Electrode Co-modified with DNA and Gold Nanoparticles
Jun ZHONG,* Zhimei QI,** Han DAI,* Chunhai FAN,* Genxi LI,*  and Naoki MATSUDA** 
*Department of Biochemistry and National Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P. R. China
**Nanoarchitectonics Research Center, AIST, Central 5, 1-1-1, Higashi, Tsukuba 305-8565, Japan
DNA and gold nanoparticles are co-immobilized at a gold electrode through elaborate self-assembly processes. This configuration has proven to be useful as a sensor for phenothiazine drugs, taking advantage of the well-known, relatively large surface area of gold nanoparticles and the strong intercalation between dsDNA and phenothiazine drugs. This modified electrode has demonstrated good sensitivity and stability towards the oxidation of two model phenothiazine drugs: promethazine and chlorpromazine. A linear dependence between the concentration of phenothiazine drugs and the peak current is observed, with a concentration range of 2.0 x 10-5 - 1.6 x 10-4 M and 1.0 x 10-5 - 1.2 x 10-4 M, and a detection limit of 1.0 x 10-5 M and 7.0 x 10-6 M, for promethazine and chlorpromazine, respectively.