P-57
医療・福祉・介護
医療・福祉・介護

Study
Study ofof thethe electricalelectrical response
response ofof
media
duringbacterial
growthcultureon
culture media during bacterial growth on
deviceaa paper-based
paper-based device■ Introduction■Food
Introduction
contamination poses sever health risks, withFood contamination
poses deaths
sever eachhealthwithworldwide
more than 300.000
yearrisks,and overworldwide
than 300.000
deathsand mostover500
millionmore
food-borne
diseases[1]. each
Oneyearof the500 million
food-borne diseases
diseases is[1].diarrhea
One ofthreateningthe mostcommonfood-relatedcommon food-related
is diarrhea
threatening
especiallyinfants and diseases
elderly people.
For example,
inespecially Thailand
infants andelderlypeople.consume
For example,
innortheast
where
the people
raw foods
northeast
Thailand
wherewere
the people
rawcontrol
foods
acutecasesof diarrhea
reportedconsume[2]. To
acute casesgoodsof diarrhea
were reported[2].processes
To control
comestible
strict hygiene
inspection
arecomestiblehowever
goods strict
inspection
arerequired,
they hygienetake longtime andprocesses
still require
required, however
they equipment.
take long timeand still
specialists
and complex
Therefore,
we require
aim tospecialiststheandhygiene
complexequipment.
Therefore,
we aim toa
improveinspection
process
by developing
improvewhich
the hygiene
inspection
by candeveloping
deviceis easy touse, low process
cost, andefficientlya
device bacteria
which is contaminationeasy to use, low
cost,
andandcanbiomaterial.
efficiently
detectin thefoods
detectin theand tobiomaterial.
Inthis bacteria
work we contamination
demonstrate that
it isfoods
possiblecorrelateIn thiswork wedemonstrate
thatbacteria
it is possible
to electricalcorrelatethedifferent
growphases of thewith thethe different
growthe bacteriawith the electricalresponse,
here
thephases
surfaceofpotential,
by measuring
the I-V
response,
here ofthethesurfacepotential,substrate.
by measuring the I-V
characteristics
contaminatedcharacteristics of the contaminated substrate.

the surface potential was determined as –V0 at I(V0)=0.
thepotential
was determinedas –V
0 at I(V0)=0.
Here,surface
we focuson the relation
between theelectricsurfaceHere,
we andfocustheonbacterial
the relation
betweenelectricdigestive
surfacepotential
growth.
Thethebacterial
potential might
and thebacterial
growth. The bacterial
digestive
products
affectthe electrochemical
propertiesof theproducts
mightthat
affectelectrochemical
propertiesof thegel.
We foundthethesurfacepotential canbe correlatedgel. We
that growth
the surface
potential
can be duringcorrelated
withthe foundbacterial
phases.
It increases
thewith the bacterial
increases
duringexponential
growth growthphase, phases.
remains Itroughly
constantin thetheexponentialphase,growthandphase,
remains decreases
roughly constantthestationary
eventuallyin the indeath
stationary phase, and eventually decreases in the death
phase.
phase.
■References■References[1]WHO, Food safety, Fact sheet N°399,[1] WHO, Food safety, Fact sheet N°399,
http://www.who.int/mediacentre/factsheets/fs399/en/
http://www.who.int/mediacentre/factsheets/fs399/en/[2] A. Vongkamma and S. Hinjoi, Acute diarrhea report inAcuteMinistry
diarrhea ofreportin[2] A., Department
Vongkamma ofandDisease
S. Hinjoi,ControlPublic2015, Department
of Disease Control Ministry of Public
2015
Health,www.boe.moph.go.th
Health,www.boe.moph.go.th[3]T. Srimongkon,
T. Ishida, K. Igarashi, and T. Enomae,[3] T. Srimongkon,
T. Ishida,
K. Igarashi,
andusing
T. Enomae,
Developmentof a bacterial
culturesystema paperDevelopmentof a bacterialmedia
culturesystemusing
a paper
platform to accommodate
and anink-jet
printingtoplatform
accommodate
media andan ink-jet
printing to, The American
Journalof Biochemistrydispense tobacteriaof Biochemistrydispensebacteria, TheandBiotechnology,2014,American
vol.10(1),Journal
pp. 81–87.

■ Experimental■ Experimental
１．Samplepreparation
１．Sample
The gridpreparationof electrodes were designed and printed on
The paper
grid of(Highelectrodes
were dpi)
designed
photo
grade 1440
with andblackprinted
toner onbyphoto apaper(High gradedpi) with
toner leaf
byusingcommercial
laser 1440
printer.
Thenblackthe goldusing was
a commercial
laser printer.
the withgoldfrieze
leaf
(24K)
put on the printed
areas andThencovered(24K)
was puton 20
theNprintedwith frieze
andpressedwith
at 170 areasC forand120covereds.
andThepressedwithgel
20 sheet
N at 170
forx120
LB agar(65Cmm35 s.
mm x 3 mm) was
The LB[3]agar
sheetin(65mmforx 3035 minmm tox equilibrate.
3 mm) waspreparedandgelsoakedwater
preparedandsheetsoakedwater
for gold
30 minto equilibrate.
Then,the[3]gelwasinputon theelectrode.
Then, the gel sheet was put on the gold electrode.

and Biotechnology, 2014, vol.10(1), pp. 81–87.

２．Measurement of the I-V characteristics
２．Measurement
the I-Vcharacteristics
The 200 L ofoffecal
bacterial
suspension was dropped
L ofof thefecalgel.
bacterial
suspension
waswasdroppedonThethe 200
surface
Then thegel sheet
cover
on thesurfaceof thethecontamination
gel sheet was(Fig.
cover
witha clean
plasticboxgel.
to Thenprevent1)
with thea clean
plastic box to wasprevent
contamination
1)
I-V characteristic
measuredevery 4 h(Fig.
underandwas field
measuredevery4 hVunderandthe I-V characteristic
the condition:
applied electric-1.0 V
to 1.0with
the V
condition:
electric
field -1.0 V to 1.0 V with
0.1
step size applied(Keithley4200-SCS).
0.1 V step size (Keithley 4200-SCS).

Figure 1. The LB agar gel sheet on electrodes for
Figure 1. The LB agar gel sheet on electrodes for
I-V characteristic curve was tested.
I-V characteristic curve was tested.

■Result and discussion
and geldiscussion■ResultThe agarshows a non-ohmic behavior in most ofagar gelshowsa non-ohmic
behaviorof
the Themeasured
voltage
range.
LB agar gel
forms inan mostelectric
the measured
range. LB agar gel forms
an electric
doublelayer atvoltage
the electrode-electrolyteinterface.
Thus,
double layer at the electrode-electrolyte interface. Thus,
代表発表者
代表発表者
所属
所属
問合せ先
問合せ先

Tithimanan Srimongkon （ティティマナン スリモンコン）
Tithimanan Srimongkon（ティティマナン スリモンコン）
国立研究開発法人
産業技術総合研究所
国立研究開発法人
産業技術総合研究所
フレキシブルエレクトロニクス研究センター
フレキシブルエレクトロニクス研究センター〒305-8565 つくば市東１－１－１つくば中央第五〒305-8565 つくば市東１－１－１つくば中央第五FAX：+81-29-861-6821
TEL：+81-29-860-5706
TEL：+81-29-860-5706
tithimanan-sri@aist.go.jp FAX：+81-29-861-6821
tithimanan-sri@aist.go.jp‒ 59 ‒■キーワード： （1）bacterial sensor■キーワード： （1）bacterialsensor（2）paper based
sensor（2）paper based
sensor（3）surface
potential
potential
Marius Buerkle・国立研究開発法人■共同研究者： （3）surface
Marius Buerkle・国立研究開発法人■共同研究者：
産業技術総合研究所、敏晴
江前・筑波大学、洋産業技術総合研究所、敏晴
史 牛島・国立研究開発法人 江前・筑波大学、洋産業技術総合研究
史
牛島・国立研究開発法人
産業技術総合研究所、伸子
福田・国立研究開発法人
産業技術総合所、伸子
研究所 福田・国立研究開発法人 産業技術総合研究所