About us

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• History

Greetings

Welcome to Lab. of Bioanalytical and physical chemistry

Our laboratory studies bioelectrochemistry, which is the chemistry of advanced biological mechanisms related to the flow of electrons and ions. In living organisms, the flow of electrons and ions generates “energy” to sustain biological activities, and drug transport and information transfer across biological membranes occur. In addition, redox enzymes play an important role in substance-energy conversion via electron transfer. Our laboratory is united in our research on these phenomena under the following themes. 

<THEME 1> Elucidation of biological phenomena involving biological membranes at the atomic, molecular, protein, and cellular levels
<THEME 2> Elucidation of life phenomena involving redox enzymes at the atomic, molecular, protein, and cellular levels.
<THEME 3> Focusing on biological functions related to Theme 1 and 2, create biomimetic devices by biomimicking advanced functions possessed by nature.

If you would like to know more about our research, please see our research projects and research introduction videos. In addition, many students from outside universities apply to our laboratory and conduct research with us every year. If you are interested in graduate school, please see “For applicants” first. If you are interested in our laboratory, please visit our website and have a chance to talk with us.

Laboratory visits and tours are available anytime, and can be arranged online. We can also arrange more detailed information, advice for entrance examinations, and discussions with students, so please feel free to contact us.
There are two ways to contact us. (Either one is acceptable.) 

1. Send an e-mail directly to Prof. Shirai (shirai.osamu.3x(At)kyoto-u.ac.jp) *Please change “At” to “@”.
2. Use the inquiry form *It is convenient because it contains all the necessary information.

 

Members

 

 

＜Student＞

 

History

As a pioneer in electroanalytical chemistry

The current laboratories of Biomolecular Chemistry and Bioanalytical and Physical Chemistry have an origin in the Department of Forest Products Chemistry, which was established in May 1925. Masuzo Shikata joined the department as an assistant professor and was promoted to professor in December of the same year. In this department, research on polarography was promoted. Polarography is a research field of electrochemistry founded by Professor J. Heyrovsky (Nobel Prize in Chemistry 1959) in Prague, and “polarograph” was invented by Shikata and Heyrovsky while they were studying in Prague. This method was developed in Japan as “Research on the electrochemistry of organic compounds” and produced many results in the study of fermentation products and quantitative analysis of trace amounts of heavy metals in biological and natural samples.
　Shikata retired in 1942, and Isamu Tachi took charge of this course. Research on the chemistry and application of hemicellulose and lignin, basic studies on interfacial electrochemistry, mechanical-vibroelectric transducers, and colloidal stability were carried out, and a theoretical system called “polarographic electrode reaction theory” was established.
　Tachi retired in 1962, and Assistant Professor Senda took charge of this course in 1964, and was promoted to Professor in 1965. In 1969, the name of this department was changed from the Department of Forest Products Chemistry to the Department of Natural Polymer Chemistry. The research on polarography was developed as a systematic study of electroanalytical chemistry, which evolved into bioelectroanalytical chemistry. Research on the electrochemistry of redox enzymes later developed into research on bioelectrocatalysis. The electrode reaction process of the mediator electron-transfer enzyme electrode was analyzed in detail, and its application to biosensors and bioreactors was attempted. On the other hand, direct electron-transfer enzyme electrode reactions that do not require a mediator were also investigated. Ion transfer at the oil-water interface was also studied, with ion permeation through biomembranes in mind. This research created a new field of ion transfer voltammetry in electroanalytical chemistry, which is the basic principle of commercially available ion sensors. The discovery of light-dependent electromotive ion pumps and their electrophysiological elucidation had a major impact on research in this field.
　In 1990, the Department of Cellular Physical Chemistry (now the Department of Biofunctional Chemistry) was established, and Tokuji Ikeda, Assistant Professor, was appointed Professor in 1992. Based on the concept of polarography, his research focused on electrochemical measurements using proteins, especially redox enzymes, and he proposed the concept of bioelectrocatalysis (enzyme electrode reaction) and realized “enzyme-functional electrodes” in which the electrode acts as an electron acceptor or electron donor for enzyme reactions. In addition, research on second and third-generation biosensors was initiated. These findings have been applied to the medical field and commercialized as blood glucose sensors. Steady-state reaction currents were formulated for polarograph catalytic currents based on enzymatic reactions, enabling the analysis of enzymatic reaction kinetics for various redox enzymes. Various bio batteries have been constructed by combining redox enzymes and substrates. He also found that a mediator-type electrode using microbial cells also responded to the current, and the microbial catalytic current made it possible to measure the growth rate of microorganisms and analyze their energy metabolism function.
　In 2005, Ikeda retired and Kenji Kano took charge of the biofunctional chemistry field. He pursued bioelectrocatalysis further and deepened his research. He has shown that mediator electron-transfer (MET) enzyme electrode reactions are useful for the construction of practical bioelectrochemical devices, devised various methods of mediator immobilization, and demonstrated that multiple enzyme reactions can be coupled in liposomes. Mediator-free direct electron transfer (DET) enzyme electrode reactions were scrutinized and the highest current density in the world at the time was achieved. Problems with conventional reaction systems and mediators related to biosensors were also pointed out, and methodologies for solutions and selection of suitable mediators were established. To elucidate ion permeation through biological membranes, we established an electrochemical analysis method for ion permeation through artificial lipid bilayers and clarified ion permeation in the presence of hydrophobic ions, ion channels, and carrier compounds. Based on these findings, he proposed a new analytical method based on the free energy linear relationship (LFER) for a novel propagation mechanism of action potentials and drug transport in nerve axons.
After Kano’s retirement in March 2020, Osamu Shirai took charge of the field in April 2020.