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ECTP2014-20thEuropeanConferenceonThermophysicalProperties
Poster P_057，3 Sept. 15:30 - 19:00
THE VISUALIZATION OF ICE CRYSTAL FORMATION BEHAVIORS AT INTRACELLULAR
FREEZINGOFPLANTCELLUSINGHIGHSPEEDCAMERA
TakakoNinagawa1;AkemiEguchi2;AiくiraNaruml3;TadashiIくonishi4;YulくioKawamura5
1GraduateStudent，KanagawaInstituteofTechnology，Japan; 2ToyoEngineeringWorks，LTD，Japan; 3DepartmentofMechanicalEngineering，KanagawaInstituteofTechnology，Japan; 40itanationalColegeofTechnology，Japan; 5BiofrontierScienceCenter，IwateUniversity，Japan. *narumi@me.kanaqawa-it.ac.io
Thecryopreservationtechniqueisesentialtothefoodandmedicalfields.However，withtheprogressofcoling，phase change inside of cel l cal led 、intracel lular fre ezing' spontaneously occurs below fre ezing point. It is widely said that intracelularfrezingcausesthedeathofcelbecauseofsomedamagetoplasmamembraneduetoicecrystal[1]. However，the present technology cannot control the ice crystal formation behaviors at intracelular frezing. Underthe above background，considering thatto obtain the ice crystal formation behaviors atthe occurrence of intracel lular fre ezing was the first step to lead to the technique of control ling intracel lular ice crystal formation，this researchwascariedouttoclarifytherelationshipbetweenicecrystalformedatintracelularfrezingandthedamage to cel ls. The high speed camera (2000framesjs) was equipped with the cryomicroscopy in order to visualize the intracelularfrezingbehaviors.Planttisuewasusedforalivingspecimeninthisresearch.JerusalemArtichoke，Allium c e p a a n d a n d S a x i f r a g a s t o l o n i f 包 r a w e r e m a in l y u s e d f o r t h e p l a n t t i s s u e . C o o l i n g r a t e w a s v a r i e d f r o m 0 . 5 O C j m in t o 1000Cjminbycontrolingtheamountofflowingliquidnitrogen. Figures1(a)and(b)showthetypicalphotographsofintracelularfrezingbehaviorsinthecasesoflower(lOCjmin) andhighercolingrates(1000Cjmin)，respectively.Thewhitebaris50ぃm;tistheelapsedtimesincethebeginningof intracelularfrezing. Fromthephotographsofhighspeedcamera，comparedwithinthecaseofhighcolingrate， typical dendritic ice crystals were formed and large ice crystal grains were seen in the case of low co oling rate. Furthermore，theprogressrateoficecrystalwaslowerandthedeformationofcelwasusualymoredistinguisheddue to intracel lular fre ezing than in the case of high co oling rate. Next，w e tried the ad ditional experiment to load micro同 electriccurrenttoplanttisue.Theloade仔"ectcausedthegrainoficecrystaltobefineranditsprogressratetobe lower.
t'=7m3 t'=21S (a)Cιοu孔ω川}ul山口19口r川il
't=7ms t'=14m只 (b)CooLingrate:10nciJllLl
lceCrystal
FrピG乙lgl'e凶 pt!raturlt:♂1oc Figure1:Thediferenceinintracelularicecrystalformationbehaviorsduetocolingrate.
FrezingI剖empe剖1百'3tu汀reι:-1oc
[1]Muldrew，K.，Acker，p.J.，日 liot，A.J.andMcGann，E.L.:TheWatertoIceTransition:ImplicationsforLivingCels，InLife intheFrozenState，Fuler，J.B.，Lane，N.andBenson，E.E.，Eds.;CRCPres.2004，pp79-101.