© 15CBMS-0001.We newly formed partially-metallized DNA nanowires, and used them for detection of deoxyribonuclease (DNase), enzyme for nonspecific DNA cleavage, which is a candidate biomarker for acute myocardial infarction. In this paper, we developed an original technique for site-specific metallization of DNA complexes consisting of single and double strands. Then, multiple 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. When DNase solutions of various concentrations were introduced, we succeeded in obtaining a definite correlation between DNase concentration and impedance increase rate in the range of 10-6 to 10-1 unit/μl.