2G17 Development of Deoxyribonuclease Sensor Using Partially-metallized DNA

We developed a microdevice for detection of Deoxyribonuclease (DNase), which is a candidate biomarker for acute myocardial infarction. DNA metallization process using intercalator molecules labeled with reducing groups permits double-stranded DNA to be specifically metallized while not permitting metallization of single-stranded DNA. Using this process, we metallized DNA complexes consisting of single strands and double strands, and fabricated partially-metallized DNA nanowires. In this paper, multiple partially-metallized DNA nanowires were immobilized between two electrodes in a microchannel, and DNase detection was achieved by measuring the increase in impedance between the electrodes after DNA cleavage by DNase. The use of partially-metallized DNA nanowires having much smaller impedance compared to non-metallized DNA generates a drastic increase of impedance after their cleavage and therefore permits much higher sensitivity. The experimental results showed a definite correlation between DNase concentration and impedance increase rate in range of 10^ to 10^ unit/μl of DNase. The present study will make DNase detection more simple, rapid, sensitive than conventional fluorometric and electrochemical detections.