Analytical Sciences

Electrochemical Control of Bioluminescence by Blocking the Adsorption of the Bacterial Luciferase Using a Mercaptobipyridine Self-assembled Monolayer

Shinya YAMASAKI,*1 Shuto YAMADA,*2 Hiroyuki TAKEMURA,*3 and Kô TAKEHARA*4

*1 Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
*2 Department of Applied Chemistry, School of Applied Sciences National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Japan
*3 Department of Chemical and Biological Science, Faculty of Science, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo, Tokyo 112-8681, Japan
*4 Department of Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 Japan

An N-butyl-N′-(4-mercaptobutyl)-4,4′-bipyridinium (4BMBP) was modified on a gold electrode to improve the electrochemical control of the bacterial luciferase (BL) luminescence system. The 4BMBP-modified gold electrode (4BMBP/Au) was able to prevent the adsorption of BL on the electrode surface, and enhanced the electrochemical regeneration rate of the reduced flavin mononucleotide (FMNH₂), which is one of the substrates of the BL luminescence reaction. By using the 4BMBP/Au, the luminescence intensity increased by about 27% compared to that of a bare gold electrode (bare Au). Moreover, the modified electrode improved the time required for analysis because the modified layer prevented BL adsorption. Even without a refreshing procedure for each measurement, a constant luminescence intensity could be observed, and the analysis time was reduced to half (about 10 min) for one sample. The 4BMBP/Au is not only useful to control of the BL luminescence system, but also for electrochemical measurements in the presence of proteins.

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