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Amperometric measurement of ds-DNA content using a peroxidase-modified electrode
Fumio Mizutani1, Soichi Yabuki, Yukari Sato
1National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566 Japan. mizutani.fumio@aist.go.jp
Abstract:
An enzyme electrode with a chemically amplified response for methylene blue (MB) was constructed from a glassy carbon electrode and a layer containing immobilized horseradish peroxidase (HRP). MB is reduced on the electrode but regenerated through the HRP-catalyzed reaction in the presence of H(2)O(2). The electroreduction/regeneration cycle for MB resulted in an amplified electrode response. The enzyme electrode was applied to the highly sensitive measurement of ds-DNA. The current for MB decreased in association with its complexation with DNA, and the current response caused by DNA was also amplified through the recycling processes. The detection limit of ds-DNA (from salmon testes) was as low as 5 ng ml(-1).