Condensed Matter Experiment Ⅱ

Soft Matter and Biophysics


Professor : Masayuki Imai
Associate Professor : Hidetake Miyata
Assistant Professor : Tetsuhiko Ohba Yuka Sakuma


 To elucidate the mechanism of cellular life is a great challenge in the next physics. The interplay of individual components in the cell makes a dynamical network system, cellular life, where we find a variety of non-linear and non-equilibrium phenomena. The purpose of this laboratory is to investigate the physical background of the cellular life from a material science point of view. We adopt two approaches “Soft Matter Physics” and “Biophysics” to reach our goal.

The soft matter group has investigated to reproduce the most basic functions of the cellular life, such as 1) self-reproduction of cell membrane (vesicle), 2) metabolic pathway coupled with the membrane traffic, 3) Coupling between membrane and information molecule, and 4) propulsion of vesicle driven by chemical stimuli, using simple soft matter assembly systems, i.e. vesicle. For example, we have succeeded in the reproduce the self-reproduction of vesicles using binary phospholipid membrane (Fig. 1) and the chemophoresis of vesicle using the micro-injection of the chemicals (Fig. 2). Using these model systems we have try to extract the basic physics to realize the cellular life and develop the protocell where interplay of self-reproduction of the vesicle, metabolism, and information molecules is realized.

The biophysics group is interested in how cells respond to electromagnetic fields. More specifically, we are currently studying the effect of 50 Hz magnetic fields and eventually to obtain results leading to the mechanism of sensing off 50 Hz magnetic fields on the cell level. The geomagnetic field sensing by a number of living organisms from bacteria to mammals has been revealed and in the former case, a magnetite-based sensing mechanism has been established. However, the effect of 50 Hz magnetic fields, although it has been shown in some cell systems, remains controversial. We are currently taking cell biological and biophysical approach, namely, the effect on DNA integrity and on protein functions, to establish the magnetic field effect.

In addition, we have developed two imaging systems; one is membrane fluidity imaging system which can observe spatial distribution of membrane fluidity at video rate, and another one is Mueller Matrix imaging system which can elucidates any change of polarization state of light induced by microscopic samples.

Fig.1 Vesicle produces a daughter vesicle inside the mother vesicle and then the daughter vesicle goes out, birthing of vesicle.
Fig.2 Chemophoresis of vesicles
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