Research

DetailRealization of network-type molecular electronics

We attempt to establish molecular neural network using self-assembly. Charge transport via molecular orbital of proteins, macromolecules or metallic complexes which are incorporated into molecular network generates threshold functions like neuron firing phenomenon. Our goal is the realization of new information processing by utilizing nano-molecular systems with the noise and/or fluctuation in electrical conductivity of molecules, effectively.

Measurement of electrical conduction on single molecules by using scanning probe microscopy

単一分子測定の図

By using scanning probe microscopy, we are studying the electrical characteristics of single molecules which are important as the components of the molecular network device. Recent progress revealed that the electrical characteristics of single molecules are significantly affected by the electrode–molecule couplings, and their active controls are very difficult. From this reason, we are trying another approach to make molecule-electrode systems having stable and strong nonlinearities by using the tunneling and hopping processes through insulator-like loose-coupling.

DetailDevelopment of time resolved Electrostatic Force Microscope

We develop a time resolved Electrostatic Force Microscopy(EFM) to image migration and extinction of charges generated by electric or light stimulation on the nanoscale materials(synthetic molecule, nanoparticle, protein and others) on insulator. Time resolution of this method is nanoseconds order
Probe tip oscillates in dynamic-mode scanning probe microscope. We can make time resolved measurement using the combination of this mechanical oscillation and photoexcitation like pump-probe method. We will erect time resolved EFM and clarify excitation dynamics of organic solar cells.

DetailInvestigation of the protein function using the nanoscale dynamical measurement

In the field of life science, the imaging technique using the fluorescence labeling method has been remarkably progressed in recently. However, “non-radiative fluorescence” interactions also play the key role in the transportation and the signal transmission of molecules with the protein. These functions of protein can be clarified by the measurements of electrostatic force, which is the driving force of transportations. We measure the dynamical measurements for example molecular interaction, charge distribution and elastic force by the frequency shift. Our study is aimed to the elucidation for the function of proteins in chemical reaction theory and physical chemistry.

Chemical imaging technique with ambient ionization mass spectrometry

大塚先生 研究概要

Scanning probe electrospray ionization mass spectrometry (SPESI-MS) is a fusion technique of the scanning probe microscopy (SPM) and the electrospray ionization mass spectrometry (ESI-MS). The flow of charged solvents at the end of a capillary probe is utilized for the ambient sampling and ionization of chemical components in a sample. The distribution of chemical components inside samples can be visualized by the probe scanning. The results of label-free tissue imaging have been demonstrated for the application in a biomedical field. Because it is also possible to detect molecules in a chemical reaction at a solid-liquid interface, we will explore the possibility of SPESI-MS for the other research fields.

Emanated human gas analysis and pathological diagnosis using laser spectroscopy

レーザー分光 改

It is well known that the more than 1800 kinds of molecules are emanated from human body. (expiration, skin etc.) But these gases are low molecular weight with molecular weight less than 100. Emanated gas molecules from human body are metabolism product formed by the living body or intestinal bacteria, there is much metabolism information in the living body related to the condition of a patient and an oxidation stress disease and includes it. Our study is aimed to the development of the new gas analysis system with high detection efficiency using the laser spectroscopy, leading to the patient diagnostic method.

Stereodynamics at the gas-liquid interface by using the geometric-isomer selected and translationally cooled radical (and biomolecular) beam

大山先生

In general, the dominant freedoms controlling reaction are expected to shift from dynamical factors to interaction ones as the collision energy decreases. In order to elucidate the relationship between statistical factor and mode selectivity in the various processes on relaxation and on reaction, we are developing new techniques on the translational cooling and on the selection of geometric isomers for radical and biomolecules. Studies on stereodynamics at the gas-liquid interface is now in progress by using an ionic liquid beam with a translationally cooled and state-selected radical (biomolecule) beam.

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