MUI Dl£N TlT VA iTNG DyNG TRONG Y SINH
Ddng Thii^ Hdng Hgc viqn Ky thugt Qudn sir
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Torn tdt:
Cdm biin mid diin tir dd dugrc ictig dung trong nhiiu linh vuc nhu thuc phdm, hod hgc, gidm sdt mdi trudng, sdn xudt nuac hoa vd gdn ddy Id chdn dodn y ti, xu ly sinh hgc...
Thiit bi ndy do sic thay ddi dign khdng tgo ra do su hdp thy ciia chdt bay hai lin bi mat cua dien cue hogt dgng- chuih Id cdc caini biin phu polimer. Rdt iihiiu cdng ty da thiit ki vd kinh doanh sdn phdm mid dign tir Bdi bdo ndy muon giai thieu tdng quan vi nguyin ly cua cdng nghi mid diin tic, cdu trite ciia cdm biin sinh hgc ding nhu nhirng ung dung cua nd, ddc biet Id trong linh vice y sinh.
Abstract:
In the past decade, Electronic Nose instrumentation has generated much interest internationally for its potential to solve a wide variety of problems in fragrance and cosmetics production, food and everages manufacturing, chemical engineering, environmental monitoring and more recently medical diagnostic, bioprocesses. Tliis instrument measure electrical resistance changes generated by adsorption of volatiles to the surface of electro active- polymer coated sensor. Several dozen companies are now designed and selling electronic nose units globally for a wide variety of expending markets. Tlie present review includes principles of electronic nose technology, biosensor structure and applications, special in bio-electronic aspect.
I. DAT VAN DE
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Cdm bien miii difn tii dang dugc ung dyng rat nhieu trong cdc ITnh vyc nhu san xuat thyc phim, my phim, dd ndng, ky thuat hda hgc, gidm sdt mdi tmdng va gin day hem chin dodn y hgc, xu ly sinh hgc vd chin dodn bfnh can lam sdng. Chfnh nhimg tiln bg trong cdng nghf cam biln khf vd thdng tin da ldm tdng khd nang chin dodn ciia miii difn bur sinh hgc. Rdt
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nhieu cdng ty hifn nay thiet ke vd bdn cdc thiet bj miii difn tii tren todn ciu. Xuit phdt tir thyc te dd', bdi bdo mudn gidi thifu vl cdng nghf mdi trong ITnh vyc cam biln cung nhu vifc triln khai iimg dyng trong ITnh vyc y sinh.
II. HE THONG MUI DIfN TU*
Mui difn tiir Id mgt thilt bj thdng minh dugc thilt kl de phdt hifn va xiir ly phan bift cdc miii phiic tap bdng cdch sir dyng mgt mdng cdc bg cam biln. Cdc mang cam biln bao gdm mdt sd cam bien dilu chinh rgng cd khd ndng xiir ly dugc nhilu loai miii vat lifu sinh hgc vd hda chat nhay cam. Dyng cu ndy cung cip mgt ky thuat liy mdu khdng can thifp nhanh chdng vd.dom gidn dl phdt hifn vd xdc djnh mgt loat cdc hgp chit de bay hai. Chiirc nang chi'nh cua mdt mui difn tu Id bdt chudc hf thing khuru gidc cua con ngudi (hinh I).
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Miii ngudi van dugc coi Id cdng cy ca bdn de phan bift cdc miii cua mdt loat cdc sdn pham trong nganh cdng nghifp. Ndm 1961, sau nhieu no lye nghien ciiu ve cdc phdn iing oxy hod
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khii ciia cdc mui tai difn eye, Moncrieff lan dau tien da phdt trien thiet bj md phdng khiiu gidc cua con ngudi bdng ca khf. Tuy nhien, md hinh dau tien ciia mdt hf thdng difn tu phdt hifn
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mui nhan tao da dugc mieu ta trong nhirng ndm ddu thdp nien 80. Md hinh ndy bat chudc mdt sd chiirc nang ca bdn cua hf thdng khiiu gidc con ngydi.
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Cdc ca quan thy cam cua con ngudi da dugc thay the bdng mdt phan dau dd khf hiiu co hodc vd ca nhay cam. Cac diu dd nay tuomg tdc mdt cdch ddc ddo vdi cdc phan tii khf rieng le hodc
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hon hgp miii phirc tap vd bien ddi cdc phdn ung hda hgc ndy thdnh tfn hifu difn. Mdt sd loai vat lifu cam biln dang dugc su dyng trong cdng nghf miii nhan tao nhu oxit kim loai, polyme ddn difn, tinh thi dp difn vd sgi quang hgc. Mgt huomg tham kfch thfch tao ra mdt dau hifu
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ddc trung tir mdng ciia bd cdm irng ndy. Cdc mdu hodc mui ddc trung da biet se sir dung de xay dyng mdt ca sd dir lifu vd ddo tao mgt hf thdng nhdn dang khudn mdu. Nhd dd, cdc loai mui chua bilt sau dd cd the dugc phan loai vd xdc djnh.
Mdt miii difn td jdiln hinh bao gdm ba ylu to (hinh 2).:
- Cdm biln tdc dung nhu Id tl bdo cam nhdn mui d miii dgng vat. Phan tii miii din Idm cam biln thay ddi, tao ra tfn hifu difn guri di.
- Bd vi xir ly tdc dyng nhu hdnh khiiu gidc nhan cdc tfn hifu difn, phan ra timg loai de tilp tyc gui di.
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Bd mdy tfnh hoat ddng nhu nao ngudi: nhan tfn hifu difn, phan bift tir dau den, tuomg ung vdi miii gi da ghi d bd nhd vd cho kit qud hifn ra len mdn hinh.
Hinh 2. Sa do khoi chung cua mpt mdi difn tu-
Diu ra cua mang cam biln cd Ihl dugc biln ddi bdng nhieu phuang phdp nhu cdc thudt todn nhan dang khuon mau, phan tfch thanh phin chi'nh, phan tfch chirc ndng khdc bift, phan tfch cym vd mang noron nhan tao dk phan biet cdc mui. Cdng nghf ndy de sii dung, khdng tdn kem vd thdng minh. Ba thanh phin chi'nh ciia miii difn tu dugc xem xet cy the trong phdn dudi day.
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2.1. Chdt bay hai sir dung ldm chdt ddnh ddu
Khi cd dilu kifn thuan Igi vd mdt ngudn dinh dudng day du, vi sinh vat nhu nam va
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vi khuan cd the phdt trien vd tao ra cac hgp chat hiru ca bay hai (VOC) bao gdm cdc loai mgu, aldehyde, hgp chat tham, amin, cdc hgp chdt hydrocarbon do hda vd sulphuric trong qud trinh chuyen hod chat dinh dudng, vd cdc chat bay hoi dd dugc su dyng nhu chat chi thj sy tdng tmdng cua vi sinh vdt.
Maasren (1899) md td bon loai vi khudn cd the tao ra miii cua este, mercaptan, vd diia khi nau ciing vdi nude thjt. Thdm chf cgng sinh tren mdt sd vi khudn ciing tao ra cdc mui ddc trung phirc tap khi phdt trien trong mdi tmdng hiru co phiic. Omelianski (1923) Id mgt trong nhirng ngudi ddu tien nghien ciiu vi sinh vdt ty nhien tao ra miii. Mgt nhdm huang vj tao ra vi sinh vdt' mdi dd dugc gidi thifu bao gdm: (a) cdc men tham, (b) vi khudn axit axetic, (c) vi khudn axit lactic, (d) vi khuan phan buy butyric, vd (e) cdc lodi gay bfnh nhu: bfnh nhilm khuan lao.
Nhdm ndy cd the gidi phdng mgt mui tham de chju
Mui cd the dugc su dyng de chdn dodn bfnh vd da dugc sir dung bdi cd ngudi Hy Lap va Trung Qudc tir 2000 ndm tmdc cdng nguyen. Ndm 400 tmdc cdng nguyen, Hipocrates da cdng nhan hifu qud chdn dodn cua cdc miii, "NIU bfnh nhan cd mdu, mu vd can trong nude tieu vd neu nd cd miii hdi ndng thi bfnh nhan dd dugc chan dodn Id lodt bang quang", "Trong nhiing ngudi bj dnh hudng cua bfnh ho lao, neu ddm md hg khac ra ndng miii thi tmdng hgp ndy rat de tu vong "(tdc pham Hippocratic, Aphorisms IV vd V). Gdn day, chung ta cdn biet den viec su dyng cac chat bay hoi nhu mdt cdng cy de xdc djnh sdm vd chan dodn lam sdng
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cua mgt sd bfnh trong dd cd ung thu vii vd phdi, bfnh tim mach, nhiem triing dudng hd hap, tieu dudng, loet chan dang khudn ciu chuoi vd con hen cip.
2.2. Cam biin sinh hgc
phan thu hai cHa cam bien mui chfnh la bg phan cam bien sinh hoc. Cam bien sinh hgc co Ihl
•dugc hieu la mgt thiet bi phan tfch nhd gpn kit hgp mgt thanh phin cam nhan cd tfnh sinh hoc hay ngudn gdc sinh hgc (nhu mgt loai enzyme, khang thi, vi khuin hay ADN), cd thi tfch hop ben trong hoac gdn ngay tren mdt cam biln hda ly. Sau khi tuong tdc vdi mdt loai hda chat, cac tfnh chat hda ly ciia ldp cam biln (khii lugng, tfnh chit quang, difn trd...) thay ddi vd dieu nay dugc phdt hifn bdi cdc cdm biln. Nhii:ng thay ddi ndy dugc biln ddi thdnh tfn hifu difn vd se dugc xir ly sau dd. Cdc cdm biln cd thi la quang (sgi quang), difn hda (difn eye lya chgn ion), nhift (nhift kl) hodc dp difn (sdng am).
Ngodi ra, cdm bien sinh hgc cd thi dugc phan thanh hai loai rgng: cdm biln phdt hifn tryc tiep vd cam biln gidn tilp. Cam img tryc tilp dugc thilt kl theo each md cdc phan img sinh hgc cu thi dugc xac djnh tryc tilp theo thdi gian thyc bdng each do thay ddi vat ly gay ra bdi sy hinh thdnh phiic hgp.Cdn cdm iing sinh hgc phdt hifn gidn tilp do cdc sdn phim tao ra sau qua trinh phdn iing sinh hda ban diu. Mdt so loai cdm biln sinh hgc nhu dien hda, quang hgc vd dp difn cd uu thi vi khd ndng phdt hifn cdc vi khuin ciia chiing.
2.3. Xir ly tin hiiu
Sy tuomg tdc cua nhiing hgp chit bay hoi vd bl mat pdlime dan difn tao ra sy thay ddi trd khdng difn. Sy thay ddi ndy dugc do vd phan tfch bdi hf thing xiir ly du lifu. Ky thuat xiir ly dir lifu, dung de phdt hifn tfn hifu thay ddi, dugc phdn loai vd md ta vl chiic ndng lien quan din mui difn tir bao gom: Phan tfch thdnh phin chi'nh (PCA), Phdn tfch tdng hgp (CA), Phan tfch chiic ndng khac bift (Dfa), mang no-ron vd Logic md. Hifn nay, sy cdi tiln vd td hgp cua cdc ky thuat mdi dugc phdt trien dd nang cao tfnh chi'nh xdc cua cdc md hinh dy bdo.
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Nhimg hf thdng tdi uu hda dugc biet den nhu mui difn tu cd do phiic tap cao vd ddp iing dugc nhiing nhu cau ve todn hgc de cdi thifn qud trinh phan tfch du lifu. Ung dung ndy ciing Id mdt mdng nghien rat phiic tap trong nhumg ITnh vyc khdc nhu thudc vd sinh hgc
3. Ung dung cua mui dien tii-
Trong nhieu trudng hgp, khi nhiem nhiing vi sinh vat se tao ra mdt sy thay ddi ve mui tren ngudi, ddc bift Id trong hoi thd, trong nude tieu hay phan. Nhung thay ddi ndy da dugc sii
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dung de hd trg them cho chan dodn bfnh vd d mdt sd nude, miii tir bfnh nhan hay nhung chdt djch cua bfnh nhan da va dang Id cdng cu quan trgng trong chdn dodn bfnh, ddc bift Id bfnh
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ve dudng hd hap. Vifc phan bift chfnh xdc cdc bfnh viem nhiem qua dudng hd hap vdn gay nhieu khd khdn cho bdc sT, nhat Id khi vifc ndy cd nguy co gay ra nhirng thieu sdt trong khau ke dom thudc. Miii difn tu cd the khdc phyc dugc nhugc diem ndy. Nhd thiet bj ndy, m iii difn
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tu cd the hd trg bdc sy chan dodn chi'nh xdc mdt bfnh viem nhiem do vi khuan, rdi nhanh chdng ke dan nhiing loai khdng sinh phii hgp. Nhu da gidi thifu, boat ddng ciia miii difn tu dya tren sy phan bift cdc miii khdc nhau trong hoi thd cua ngudi bfnh. Thao tdc ndy lai nhd
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vao nguyen ly: Mdi loai vi khudn deu sinh ra cdc hgp chat khf ddc tnmg - gidng nhu mdi con ngudi cd diu van tay rieng bift. Mdi difn tir cd mdt bd nhd luu giir mdt loat cdc chat khf chudn ciia timg loai vi khuan, do dd nd cd the "ddnh hoi" chi'nh xdc "miii" cua tdc nhan gay bfnh trong hai thd. Sau khi da cd ket qud phan tfch, thiet bj se ty ddng ggi y cho ngudi dimg mpt so loai khdng sinh trj bfnh thi'ch hgp vd hifu qud nhat. Khi tien hdnh thir nghifm ddu tien nhdm vdo bfnh viem phdi, mui difn tu da xac djnh dugc 92% sd ca bfnh trong tdng sd 25
benh nhan. Trong thii' nghifm sir dung mui difn tu- phdt hifn bfnh viem xoang vd kit qua Cling rit kha quan 82% so ngudi mdc benh da dugc nh^n difn chfnh xdc.
Hien nay "nuiii dien tii'" cdn co kha ndng phut hifn ngudi hiit thuoc Id mgt cdch nhanh chdng va chi'nh xac ma khdng cin thir mdu hoac nude tilu. Vdi vifc sir dyng 32 bg cam biln cd the thay dii difn trd khi phat hifn hgp chit huu ca bay hoi (VOCs) trong hai thd nlu ngudi dd hilt thudc. Cac nha khoa hgc cung tiln hanh nhilu thir nghifm, trong dd cd kiem tra chit djch trong CO thi vd miii difn tir c6 thi cho ra kit qua chfnh xdc trong vdi phiit. Hifn tai, cdc nhd nghien ciru thudng sir dung cdng nghf danh gid hdnh dgng hut thudc Id thdng qua khf carbon monoxide (CO) phd ra qua hai thd. Mui difn tOr trong tuang lai cd thi dugc diing dk Idm xet nghifm cho cdc bfnh nhan dk dy phdng vl tinh tr^ng sire khde cua minh. Tfnh ndng cua mui difn tii dang dugc thdm djnh sau hem, sau dd nd se dugc nang cap de phdt hifn mgt sd cdn bfnh phiirc tap hom nhu ung thu phdi vd cdc bfnh ve gan, th$n.
III. KET LUAN
Trong bdi ndy chiing tdi dd xem xet md td nguyen ly ciing nhu cdc iing dung cua hf thdng cdm biln miii difn tii trong ITnh vyc chdm sdc siic khde. Day Id phat trien mdi ciia ngdnh khoa hgc cd ten Id phdng sinh hgc (biomimetics). Bd Id ngdnh khoa hgc bat chudc cdc bg phdn nhdy cdm d sinh vdt de Idm ra cdc mdy mdc phyc vy con ngudi. Tuy Id cdng nghf mdi nhung miii difn tii hira hen se dem lai nhieu tiem nang trong vifc dy phdng cfing nhu chdn dodn vd dieu trj bfnh trong tuomg lai.
TAI LIEU THAM KHAO
[I]. A. K. Pavlou, A. P. F. Turner, N. Magan, "Recognition of anaerobic bacteria isolates in vitro using electronic nose technology", Letter in Applied Microbiology, Vol. 35, 2002.
[2]. V. Rossi, R. Talon, J. L. Berdague, "Rapid discrimination of Micrococcaceae species using semiconductor gas sensors". Journal of Microbiological Methods, Vol. 24,
1995.
[3]. A. P F Turner, N. Magan, "Electronic Noses and disease diagnostic". Nature Review in Microbiology, Vol. 2, 2004.
[4]. Huynh Luang NghTa, Cam biln vd do ludng y sinh, Hgc vifn Ky thu^t Quan su, 2007.
