Activation and inactivation processes of cell
viability by atmospheric pressure plasma flow
We aim at clarifying the effects on cells by chemicalspecies generated by plasma, and aim for thefundamental study and the application.
We have now studied about theactivation
andinactivation
mechanism of cell viability by aplasma flow, and the transportmechanism of chemical species
generated by the plasma flow.
T. Sato et al., J. Phys. D: Appl. Phys., 44 (2011), 372001
M. Yokoyama et al., BBRC, 450 (2014), 1266
T. Miyahara et al., AIP Advances, 4 (2014), 047115

Fluorescence image ofHeLa cells. Regular (Left).
Cell death after exposure(Right).

○Microwave argon plasma flowTo
reduce infection risks of new influenza,
nosocomial infection and so on, and to develop nextgeneration medical instruments, we aim at clarifying
generation and transportation mechanisms of aplasma flow by experimental and computational
analyses and we also aim at identifying the central
factor of sterilization effect and clarifying sterilization
mechanism.

N2＊

Visualization

Effect of plasma flow on E.
coli. Treated (R)T. Sato et al., Applied Physics Letters, 89 (2006), 073902.
T. Sato et al., IEEE Trans. Industry Appli., 42 (2006), 399.
T. Sato et al., IEEE Trans. Industry Appli., 43 (2007), 1159.
T. Miyahara et. al, Europhysics Letters, 86 (2009), 45001.
T. Sato et al., New Journal of Physics, 11 (2009), 115018.
PCT/JP2005/15431, 特願2007-001999, Patent 2008-06604○Sterilization in a tube
Application to medical equipments such as catheter
sterilization by radical generation, transport andconcentration using plasma flow control. For example,optimum sterilization conditions are 5 min, 70 ℃ and
13 W for a tube of 100 mm length and 3 mm i.d.

Twin vortex

N2*emission

Biological Nanoscale
Reactive Flow Laboratory
Professor Takehiko Sato Assistant Professor Siwei Liu
Contact：takehiko.sato.d7@tohoku.ac.jp

Sterilization device and mechanism by lowtemperature plasma at atmospheric pressure

PhotographInstitute of Fluid ScienceTohoku University

Computaional analyisis ofstreamer propagation

T. Sato et al., Plasma Processes and Polymers, 5 (2008), 606.
T. Sato et al.., IEEE Trans. Industry Appli., 45 (2009) , 44.
Patent JP4898635，JP4902842
PCT/JP2006/315958, etc.

As a low-temperature plasma flow at atmospheric pressure iseasily capable of generating heat, light, chemical species,
charged particles, shock wave, etc., recently, a research on asterilization and a plasma treatment has started using thosephysical features. The biological nanoscale reactive flowlaboratory aims at a fundamental study and applications of“plasma medicine”, which is expected to become a nextgeneration medical technology, through the studies on
activation and inactivation processes of cells, development of aplasma sterilization method, phenomena of reactive flow
dynamics and nanoscale flow dynamics for a gas-liquid plasma
and interactions between a plasma flow and cell/bacteria.

Introduction

Plasma has been
applied to a wide range
Spraying, Weldingof fields, and it isEnvironmental
Environmental
MPD
MPD
treatment
treatment
thrusterthruster
VOC, NOx
necessary to approachdecomposition
Plasma flowLightfrom different points ofLight source
sourceFluorescent，HID lamp，
Nuclear
Nuclear
Plasma display, Laser
view,
e.g.,
electric,
fusionfusionBiotechnology,
chemical, material, andMedicine
Semiconductor
Sterilization,
Nano-process,Treatment,
thermal fluid fields.
Thin-film coatingCosmetic
We study about generation and transportation mechanismsof radicals by plasma flow at atmospheric pressure generated in
gas-liquid flow, interaction mechanisms between plasma andbiological objects, bubble generation and collapse processes by
gas-liquid plasma flow, and numerical analyses of reaction
processes.
Also, we promote the basic research for thepractical use, through joint researches with universities,
research institutes, and companies all over the world.
Heat,
Light，
Light，
RadicalMaterial
Material
processing
processing

MHD
Generator

Electric andMagnetic fields

JSME Fluids Engineering Division News Letter “Plasma flow at atmospheric pressure”,December 2007. http://www.jsme-fed.org/newsletters/index.html

Initiation and propagation mechanism ofunderwater streamers
We clarified that a primary streamer
propagated intermittently synchronizedwith appearance of pulsed currents withvelocity of 2.5 km/s and a secondary
streamer propagated with around 20km/s during a continuous current
Propagation ofappears.
H. Fujita et al., J. Appl. Phys. 113 (2013), 113304.
H. Fujita et al., EPL, 105 (2014), 15003.
H. Fujita et al., J. Appl. Phys. 116 (2014), 213301.

underwater primary
stremer

Chemical transport by plasma actuator

Dynamics of plasma-induced cavitation bubble

To apply medical applications
and environmental treatment,
wehaveclarifiedflow
patterns and mechanisms ofplasma induced flow. Bullet
type of thermal flow is High speed images ofgenerated when plasma is plasma induced flow in
generated from the tip of the the plasma-water system.
electrodeto
thewater T. Shimizu et al., New J. Phys.,(2011), 053025.
surface. This flow generates 13T. Shimizu et al., J. Photochem.
circulating flow in water and Sci. Tech., 24 (2011), 421R.
enhancesthechemicaltransport
generatedbyplasma.

We aim at developing a medical instrument
using plasma in water by investigating
dynamics of rebound bubbles. The rebounddynamics changes due to inclusion ofhydrogen gas, which is non-condensation Bubble dynamics
gas, when the bubbles are generated by of laser/sparkinduced bubble
plasma such as laser or spark.

Collaboration researches: Max-Planck-Institute for Extraterrestrial
Physics(Germany), Ecole Polytechnique Federale de Lausanne(Switzerland), Shizuoka University, Shinshu University, Tohoku
University, Oita University, Tohoku Medical and Pharmaceutical
University, etc.

T. Sato et al., APL102 (2013), 074105.

Development of plasma nano-bubbles
We aim at developing plasma nanobubbles which are stable and easy
handling to apply for medical intruments.
It was clarified that nano-scale bubbles
around 100 nm were generated when
streamer bubble channels in water Bubbule size
collapsed.
distribution by DLS
T. Sato et al., J. Phys.: Conf. Ser. 656 (2015) 012036
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