Imaging of enzyme activity by scanning electrochemical microscope equipped with a feedback control for substrate-probe distance

Daisuke Oyamatsu, Yu Hirano, Norihiro Kanaya, Yoshiaki Mase, Matsuhiko Nishizawa, Tomokazu Matsue

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

The enzymatic activity of diaphorase (Dp) immobilized on a solid substrate was characterized using a scanning electrochemical microscope (SECM) with shear force feedback to control the substrate-probe distance. The shear force between the substrate and the probe was monitored with a tuning fork-type quartz crystal and used as the feedback control to set the microelectrode probe close to the substrate surface. The sensitivity and the contrast of the SECM image were improved in the constant distance mode (distance, 50 nm) with the shear force feedback compared to the image in the constant height mode without the feedback. By using this system, the SECM and topographic images of the immobilized diaphorase were simultaneously measured. The microelectrode tip used in this study was ground aslant like a syringe needle in order to obtain the shaper topographic images. This shape was also effective for avoiding the interference during the diffusion of the enzyme substrates.

Original languageEnglish
Pages (from-to)115-121
Number of pages7
JournalBioelectrochemistry
Volume60
Issue number1-2
DOIs
Publication statusPublished - 2003 Aug

Keywords

  • Diaphorase
  • Feedback control
  • SECM
  • Shear force

ASJC Scopus subject areas

  • Biophysics
  • Physical and Theoretical Chemistry
  • Electrochemistry

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