今(jin)天小編(bian)主(zhu)要(yao)介(jie)紹(shao)下(xia)微(wei)流(liu)控(kong)芯片技(ji)術詳(xiang)解:

 

1、微(wei)流(liu)控(kong)芯片的基(ji)質材料(liao)

        基(ji)質材料(liao)是(shi)微(wei)流(liu)控(kong)芯片的載(zai)體(ti),在(zai)微(wei)流(liu)控(kong)芯片發展的初(chu)期(qi),矽材(cai)料(liao)作(zuo)為(wei)構建微(wei)流(liu)控(kong)芯片的首(shou)選(xuan)材(cai)料(liao)而(er)被廣泛使(shi)用(yong),這主(zhu)要(yao)歸因於業(ye)已(yi)成熟(shu)的半導(dao)體(ti)技(ji)術.但(dan)是隨(sui)著研究的不斷(duan)深(shen)入(ru)和應(ying)用(yong)領域(yu)的不斷(duan)拓(tuo)展(zhan),它(ta)表(biao)現(xian)出了不同(tong)程度(du)的局(ju)限(xian)性(xing):矽材(cai)料(liao)屬於半導(dao)體(ti),不能(neng)承(cheng)受高電(dian)壓,此(ci)外(wai),矽(gui)材(cai)料(liao)不透(tou)明,與(yu)光學(xue)檢測技(ji)術不兼(jian)容(rong).

        玻璃材(cai)料(liao)具(ju)有(you)很好的電(dian)滲性(xing)質和(he)優(you)良(liang)的光學(xue)性(xing)質,無(wu)論(lun)是從(cong)其物(wu)理(li)性(xing)質還(hai)是化學性(xing)質來(lai)講,都(dou)非常(chang)適(shi)合(he)於微(wei)流(liu)控(kong)芯片的制(zhi)作(zuo),但是它(ta)的光刻和蝕(shi)刻技(ji)術工(gong)藝復(fu)雜(za)、費時(shi),制(zhi)作(zuo)成本過(guo)高,這些(xie)因素制(zhi)約了玻璃微(wei)流(liu)控(kong)芯片的應(ying)用(yong)和(he)推(tui)廣.

        因此(ci),研究者們開(kai)始(shi)把更(geng)多的註意力轉(zhuan)向(xiang)了原(yuan)材(cai)料(liao)便(bian)宜(yi)、加工(gong)制(zhi)作(zuo)簡(jian)單(dan)的高(gao)分(fen)子聚合物(wu),目前(qian),以聚二甲(jia)基(ji)矽氧烷(wan)(PolydiMethyl-Siloxane,PDMS)為(wei)代表的有(you)機高(gao)分子(zi)聚合物(wu)已(yi)成為微(wei)流(liu)控(kong)芯片研究的熱點(dian),PDMS表(biao)現(xian)出了非常(chang)理(li)想的材(cai)料(liao)特(te)性(xing):良好的絕緣性(xing),能(neng)承(cheng)受高電(dian)壓,已廣泛應(ying)用(yong)於各(ge)種(zhong)毛細管電(dian)泳微(wei)芯片的制(zhi)作(zuo);熱穩定(ding)性(xing)高,適(shi)合(he)加工(gong)各(ge)種(zhong)生化反(fan)應芯片;具(ju)有(you)很高的生(sheng)物(wu)兼(jian)容性(xing)和氣(qi)體(ti)通透(tou)性(xing),可以用(yong)於細胞培(pei)養(yang);同(tong)時(shi)具(ju)有(you)優(you)良(liang)的光學(xue)特性(xing),可應用(yong)於多種(zhong)光學(xue)檢測系統;彈(dan)性(xing)模量低(di),適(shi)合(he)於制(zhi)作(zuo)微(wei)流(liu)體(ti)控(kong)制(zhi)器(qi)件,如(ru)泵(beng)膜(mo)等(deng).此(ci)外(wai),PDMS還(hai)可以和(he)矽(gui)、氮化矽(gui)、氧化(hua)矽(gui)、玻璃等(deng)許(xu)多材料(liao)形(xing)成(cheng)很好的密(mi)封.此(ci)外(wai),較(jiao)常(chang)用(yong)的高(gao)分(fen)子聚合物(wu)還(hai)包括聚甲基(ji)丙烯(xi)酸(suan)甲酯(zhi)(PolyMethylMethAcrylate,PMMA)、聚碳酸酯(zhi)(PolyCarbonate,PC)等(deng).

 

2、微(wei)流(liu)控(kong)芯片的加工(gong)技(ji)術

        微(wei)細加工(gong)技(ji)術是(shi)微(wei)流(liu)控(kong)芯片發展的前(qian)提(ti)條(tiao)件,微(wei)流(liu)控(kong)芯片的制(zhi)作(zuo)技(ji)術首(shou)先起源於制(zhi)造半導(dao)體(ti)及(ji)集(ji)成(cheng)電(dian)路芯片所廣泛采(cai)用(yong)的光刻(Lithography)和蝕(shi)刻技(ji)術(Etching),目前(qian)已經廣泛地(di)用(yong)於矽片(pian)、玻璃和(he)石(shi)英等(deng)基(ji)質材料(liao)上微(wei)流(liu)體(ti)網(wang)絡的制(zhi)作(zuo).其微(wei)制(zhi)造工(gong)藝為(wei):首(shou)先通過(guo)光學(xue)制(zhi)板(ban)照(zhao)相技(ji)術制(zhi)備包括微(wei)流(liu)控(kong)芯片圖案(an)的掩(yan)模,制(zhi)備好的掩(yan)模通常(chang)是鍍(du)有(you)鉻層(ceng)的石(shi)英玻璃板(ban);然(ran)後用(yong)甩膠機均勻(yun)地(di)在(zai)芯片表面塗敷(fu)壹(yi)層(ceng)光刻膠,在(zai)紫外(wai)光下(xia)進(jin)行曝光,顯(xian)影(ying).上述(shu)工(gong)作完(wan)成之後,用(yong)相(xiang)應(ying)的腐蝕(shi)劑對(dui)芯片進(jin)行蝕(shi)刻,蝕(shi)刻完成(cheng)後,去除剩(sheng)余的光刻膠便(bian)可獲(huo)得(de)所需的芯片微(wei)細結構(gou).該(gai)方(fang)法工(gong)藝周(zhou)期長(chang)、制(zhi)作(zuo)成本高(gao),但(dan)其微(wei)加工(gong)技(ji)術非(fei)常(chang)成熟(shu).

        與(yu)矽片(pian)、玻璃材(cai)料(liao)不同(tong)的是(shi),可用(yong)於微(wei)流(liu)控(kong)芯片加工(gong)制(zhi)作(zuo)的高(gao)分(fen)子聚合物(wu)種(zhong)類(lei)繁(fan)多,而且各(ge)材料(liao)之(zhi)間(jian)的物(wu)理(li)化學(xue)性(xing)質差(cha)別(bie)很大(da),所以它(ta)們(men)的微(wei)加工(gong)技(ji)術表(biao)現(xian)出了壹定(ding)的多樣性(xing),目前(qian)主(zhu)要(yao)有(you)模塑(su)法(fa)、熱壓法、LIGA技(ji)術、激(ji)光燒(shao)蝕(shi)技(ji)術和(he)軟光刻法等(deng).

        a、模塑(su)法(fa)(Injection Molding)

        是(shi)指通過(guo)光刻掩模技(ji)術制(zhi)得(de)凸起的微(wei)流(liu)控(kong)芯片陽(yang)模,然(ran)後在陽(yang)模上澆(jiao)註液態的高(gao)分(fen)子聚合物(wu),當高(gao)分(fen)子(zi)聚合物(wu)完(wan)全固化(hua)後將(jiang)其與(yu)陽(yang)模剝離(li)即(ji)可得到(dao)具(ju)有(you)微(wei)流(liu)體(ti)網(wang)絡的基(ji)片,適(shi)宜(yi)采(cai)用(yong)模塑(su)法(fa)的高(gao)分(fen)子材(cai)料(liao)應(ying)該(gai)具(ju)有(you)很低(di)的黏(nian)度(du)和(he)很低(di)的固化(hua)溫度,如PDMS,環氧(yang)樹脂,聚四氟(fu)乙(yi)烯等(deng)材(cai)料(liao).

        b、熱壓法

        也(ye)是壹種(zhong)需要(yao)陽(yang)模的微(wei)流(liu)控(kong)芯片制(zhi)造技(ji)術,該(gai)技(ji)術主(zhu)要(yao)利用(yong)了高分(fen)子(zi)聚合物(wu)的玻璃轉(zhuan)化(hua)溫度.與(yu)模塑(su)法(fa)相(xiang)比,熱壓法制(zhi)得(de)的微(wei)通道(dao)重(zhong)復(fu)性(xing)較(jiao)差(cha),而(er)且(qie)管道(dao)易產(chan)生(sheng)變形,操(cao)作(zuo)條(tiao)件相(xiang)對苛刻.該方(fang)法主(zhu)要(yao)應用(yong)於熱塑(su)性(xing)材料(liao)的加工(gong),如PMMA和(he)PC等(deng).

        c、激(ji)光燒(shao)蝕(shi)(Laser Ablation)

        是壹(yi)種(zhong)新型(xing)的微(wei)細加工(gong)技(ji)術,它(ta)是(shi)通過(guo)紫外(wai)激光降(jiang)解高分子(zi)聚合物(wu),適(shi)宜(yi)激(ji)光燒(shao)蝕(shi)加工(gong)的材(cai)料(liao)有(you)PMMA、聚苯乙(yi)烯(xi)、硝化(hua)纖維(wei)等(deng).

        微(wei)流(liu)控(kong)芯片技(ji)術詳(xiang)解_微(wei)流(liu)控(kong)技(ji)術在(zai)生物(wu)醫(yi)學上的應(ying)用(yong)3、微(wei)流(liu)控(kong)芯片的微(wei)流(liu)體(ti)控(kong)制(zhi)技(ji)術微(wei)流(liu)體(ti)操(cao)縱技(ji)術是(shi)微(wei)流(liu)控(kong)芯片技(ji)術中(zhong)最(zui)重(zhong)要(yao)的壹(yi)個(ge)研究領域(yu)之(zhi)壹,通過(guo)各(ge)種(zhong)機械(xie)或(huo)非機(ji)械(xie)力實(shi)現(xian)對流(liu)體(ti)的驅(qu)動和控(kong)制(zhi).依(yi)據微(wei)流(liu)體(ti)驅(qu)動體(ti)系中(zhong)有(you)無(wu)機(ji)械(xie)活(huo)動(dong)部(bu)件,可以將(jiang)其分為機械(xie)和(he)非(fei)機(ji)械(xie)驅(qu)動系統.

        a、機(ji)械(xie)驅(qu)動系統

        主(zhu)要(yao)包括壓電(dian)微(wei)泵(beng)、靜電(dian)微(wei)泵(beng)等(deng),它(ta)主(zhu)要(yao)是通過(guo)靜電(dian)、壓電(dian)等(deng)不同(tong)方(fang)法來(lai)觸發引起(qi)的機(ji)械(xie)部(bu)件的運(yun)動(dong),從而(er)為微(wei)流(liu)體(ti)提(ti)供(gong)動力源(yuan),這種(zhong)泵(beng)的優(you)點(dian)是(shi)任(ren)何流體(ti)都(dou)可以推(tui)動,但(dan)其所驅(qu)動的流(liu)體(ti)呈(cheng)脈(mai)沖狀而(er)不是(shi)連續式(shi)的.

        b、非(fei)機(ji)械(xie)驅(qu)動系統

        主(zhu)要(yao)包括電(dian)滲泵(beng)、熱毛(mao)細管泵(beng)等(deng),其中(zhong)電(dian)滲泵(beng)是微(wei)流(liu)控(kong)芯片系統中(zhong)最(zui)常(chang)用(yong)的壹(yi)種(zhong)驅(qu)動力,相(xiang)對(dui)於微(wei)機(ji)械(xie)壓力驅(qu)動的泵(beng)來(lai)說(shuo),電(dian)滲泵(beng)有(you)很多優(you)點(dian):如(ru)電(dian)滲泵(beng)易於制(zhi)作(zuo)而且沒(mei)有(you)任何(he)移動(dong)部(bu)件,電(dian)滲泵(beng)的樣(yang)品(pin)柱(zhu)只(zhi)有(you)少(shao)量的擴(kuo)散(san),此(ci)外(wai),可以采(cai)用(yong)改(gai)變(bian)微(wei)通道(dao)壁(bi)x(電(dian)勢)的方(fang)法來(lai)進(jin)壹步(bu)控(kong)制(zhi)電(dian)滲流的量和(he)方(fang)向.

 

        4、微(wei)流(liu)控(kong)芯片檢測技(ji)術

        微(wei)流(liu)控(kong)芯片的結構(gou)特(te)征(zheng)決定了其檢測技(ji)術的特(te)殊性(xing),與(yu)傳(chuan)統檢測儀器(qi)相(xiang)比(bi),微(wei)流(liu)控(kong)芯片對其檢測系統提(ti)出了更(geng)高(gao)的要(yao)求(qiu),如要(yao)求(qiu)靈敏度(du)高(gao)、響應(ying)速(su)度快(kuai)、具(ju)有(you)平行分析功能(neng)和(he)便(bian)攜式(shi)特(te)征(zheng)等(deng),目前(qian)基(ji)於不同(tong)原(yuan)理(li)的很多檢測技(ji)術都(dou)已經應用(yong)到(dao)微(wei)流(liu)控(kong)芯片的研究中(zhong),主(zhu)要(yao)有(you)光學(xue)檢測、電(dian)化學檢測、質譜(pu)等(deng)方(fang)法.

        a、光學(xue)檢測

        光學(xue)檢測是微(wei)流(liu)控(kong)芯片檢測方(fang)法中(zhong)應用(yong)最(zui)廣的壹(yi)種(zhong),其優(you)點(dian)在(zai)於靈敏度(du)高(gao)、實(shi)用(yong)性(xing)強,且(qie)檢測器(qi)與(yu)分析對象不需(xu)直接(jie)接(jie)觸(chu).其中(zhong)激光誘(you)導(dao)熒(ying)光檢測(Laser Induced Fluorescence,LIF)是目前(qian)最(zui)靈敏的檢測方(fang)法之(zhi)壹,其靈敏度(du)達(da)到10-9mol/L~10-12mol/L,對(dui)於某些(xie)熒光效(xiao)率(lv)高的分(fen)子(zi),其檢測能(neng)力可以達(da)到單(dan)分(fen)子(zi)水平,因此(ci)它(ta)也(ye)是(shi)當前(qian)商(shang)品(pin)化微(wei)流(liu)控(kong)系統中(zhong)唯(wei)壹(yi)被采(cai)用(yong)的檢測器(qi).但(dan)該(gai)檢測設備價(jia)格(ge)昂貴,而且(qie)體(ti)積(ji)龐大(da),與(yu)微(wei)尺(chi)寸的微(wei)流(liu)控(kong)芯片極不匹配,壹(yi)定(ding)程度上限制(zhi)了其廣泛推(tui)廣與(yu)應用(yong).

        b、電(dian)化學檢測

        基(ji)於電(dian)化學檢測原(yuan)理(li)的檢測系統可以說(shuo)是(shi)最(zui)完整(zheng)的、最(zui)集成、最(zui)理(li)想的芯片檢測系統之(zhi)壹(yi),這主(zhu)要(yao)有(you)兩方(fang)面的原(yuan)因:壹(yi)方(fang)面,微(wei)電(dian)極的制(zhi)造技(ji)術與(yu)當前(qian)微(wei)流(liu)控(kong)芯片的加工(gong)工(gong)藝是(shi)完全兼(jian)容的,可以實(shi)現(xian)大(da)批量生(sheng)產(chan);另(ling)壹(yi)方(fang)面,電(dian)化學檢測具(ju)有(you)靈敏度(du)高(gao)、選(xuan)擇(ze)性(xing)好、不受光程(cheng)和樣品渾濁(zhuo)度(du)影(ying)響等(deng)優(you)點(dian),且(qie)只(zhi)需要(yao)極少(shao)的外(wai)圍(wei)輔助設(she)備即可實(shi)現(xian)快(kuai)速(su)檢測,圖1給(gei)出的是(shi)壹(yi)種(zhong)便攜式(shi)電(dian)化學檢測系統.無(wu)疑(yi),基(ji)於電(dian)化學原(yuan)理(li)的芯片檢測技(ji)術代表未(wei)來(lai)芯片檢測器(qi)的壹(yi)個(ge)重(zhong)要(yao)發展方(fang)向,顯(xian)示(shi)了巨大(da)的應(ying)用(yong)價(jia)值和(he)潛力.

        c、質(zhi)譜(pu)檢測

        質譜(pu)檢測技(ji)術作(zuo)為生(sheng)物(wu)化(hua)學分析的重(zhong)要(yao)手段(duan),由於能(neng)夠提供(gong)試(shi)樣(yang)組(zu)分(fen)中(zhong)生物(wu)大(da)分子(zi)的基(ji)本結構(gou)和(he)定量信(xin)息,所以在微(wei)流(liu)控(kong)芯片檢測器(qi)中(zhong)表現(xian)出了巨大(da)潛力,但(dan)當前(qian)質(zhi)譜(pu)檢測的瓶頸(jing)在於質譜(pu)儀(yi)與(yu)微(wei)流(liu)控(kong)芯片的接(jie)口(kou)問(wen)題.