企業(yè)戰(zhàn)略論文半導(dǎo)體納米材料的制備及其在生物分析中的應(yīng)用

1、半導(dǎo)體納米材料的制備及其在生物分析中的應(yīng)用 半導(dǎo)體納米材料的制備及其在生物分析中的應(yīng)用 【中文摘要】 半導(dǎo)體量子點(quantum dots,qds)是近年來被廣泛研究的一類發(fā)光物質(zhì),當(dāng)其直徑小于其激子玻爾直徑(一般小于10 nm)時,就會表現(xiàn)出特殊的物理和化學(xué)性質(zhì)。半導(dǎo)體量子點的這種特殊結(jié)構(gòu)導(dǎo)致它具有量子尺寸效應(yīng)、介電限域效應(yīng)、表面效應(yīng)、宏觀量子隧道效應(yīng)等特性,并由此派生出半導(dǎo)體量子點獨特的發(fā)光特性。這些特性使它們在生命科學(xué)、分析科學(xué)、材料科學(xué)、免疫醫(yī)學(xué)、檢驗檢疫等傳統(tǒng)及新興領(lǐng)域中發(fā)揮著越來越重要的作用。與傳統(tǒng)的有機熒光染料相比,量子點具有寬激發(fā)、窄發(fā)射、發(fā)射峰較窄并且對稱、發(fā)射波長可通過控

2、制它的尺寸大小和組成來調(diào)節(jié)、熒光強度及穩(wěn)定性是普通熒光染料的100倍左右、生物體系中幾乎沒有光漂白現(xiàn)象、生物相容性好等優(yōu)點,可以用作熒光探針對生物樣品和細(xì)胞進(jìn)行染色。近年來在納米技術(shù)方面所取得的研究進(jìn)展使得納米材料可以設(shè)計為高靈敏度的化學(xué)或生物傳感器。納米粒子與生物識別物質(zhì)或結(jié)構(gòu)相結(jié)合能夠?qū)δ骋惶囟ǖ姆治鑫锂a(chǎn)生響應(yīng),從而形成了納米生物傳感器。一維納米材料(納米棒、納米帶、納米管以及納米線)由于其在介觀物理及納米器件制造領(lǐng)域獨特的應(yīng)用潛力而逐步成為新的研究熱點,同時一維半導(dǎo)體納米材料也因本身所具有的許多獨特的光學(xué)性質(zhì)而獲得了快速發(fā)展。理論研究比較成熟的是cdse納米棒,與球形半導(dǎo)體納米粒子相比,

3、cdse納米棒的斯托克斯位移要大的多,并且在沿聚乙烯-丁烯整齊排列的長軸方向上出現(xiàn)極化發(fā)射現(xiàn)象,這對于半導(dǎo)體納米棒用于生物材料標(biāo)記時確定標(biāo)記材料的取向很有幫助。cdse/cds/zns納米棒作為探針用作熒光標(biāo)記就要比半導(dǎo)體量子點亮的多。最近相繼報道了很多一維半導(dǎo)體材料的合成,然而,合成一維納米管卻并不多見,究其原因是因為空心結(jié)構(gòu)的形成條件比較苛刻。眾所周知,花菁是一類可以通過改變共軛鏈的長度來調(diào)節(jié)吸收和發(fā)射波長的熒光染料。花菁-5是其中一個斯托克斯位移較大且發(fā)射在近紅外的成員?；ㄝ?5在600 nm左右的吸收較強,可以與cdte量子點的發(fā)射峰位置重疊,兩者相結(jié)合可以組建熒光共振能量轉(zhuǎn)移體系(f

4、ret)。fret因其對距離的敏感性,廣泛地被應(yīng)用于生物大分子結(jié)構(gòu)、性質(zhì)、反應(yīng)機理以及定量分析等方面的研究。酶性dna是近年來發(fā)展比較迅速的、與蛋白質(zhì)酶和酶性rna作用相似的酶家族新成員,另外金屬離子作為輔助因子可以增強酶性dna的活性。利用這個性質(zhì),可以通過體外選擇來篩選合適的dna鏈檢測金屬離子。本文綜述了半導(dǎo)體量子點在生物檢測中的應(yīng)用、空心納米結(jié)構(gòu)的制備以及潛在的應(yīng)用價值、酶性dna作為檢測金屬離子探針的應(yīng)用。在此基礎(chǔ)上,分別開展了以下幾方面工作:1、利用半導(dǎo)體納米粒子在水油界面的自組裝合成了油溶的一維cdte納米管和納米線,克服了傳統(tǒng)油相合成法的缺點。研究中分別考察了多個影響因素從而得

5、到了最優(yōu)合成條件;2、設(shè)計組裝了以cdte量子點(qds)和花菁-5(cy-5)之間的熒光共振能量轉(zhuǎn)移( fret )為基礎(chǔ)的納米生物傳感器:qds- dnazyme-cy.5,預(yù)期目標(biāo)是實現(xiàn)生物體內(nèi)銅離子的直接測定。在沒有銅離子存在的情況下,花菁-5猝滅cdte的熒光。一旦加入銅離子后,銅離子特異性打斷dna結(jié)合位點,dna鏈不可逆斷開,花菁-5遠(yuǎn)離cdte使得熒光共振能量轉(zhuǎn)移現(xiàn)象消失,cdte的熒光恢復(fù)從而達(dá)到測定銅離子的目的?！居⑽恼?in recent years, quantum dots have been widely investigated as a class of l

6、uminescent material. when their size is comparable to the size of bohr diameter for exciton, they exhibit special physical and chemical properties which possess the quantum size effects, dielectric confinement effects, surface effects, macroscopic quantum tunneling effect and so on. so the quantum d

7、ots with these special optical characteristics applied in the fluorescent biological analytical applications have become a wide research focus. compared to conventional organic dyes, qds possess many advantages, such as narrower emission spectra, tunable maximum emission wavelength with changeable s

8、izes and compositions, photostability, high brightness, long fluorescence lifetime and biocompatibility, which have been successfully used as fluorescent probe or sensor in the imaging of biological samples and cells. following the development on the nanotechnology, sensitive chemical and biology se

9、nsor can be designed from nanomaterial. nanoparticles and biological material compose the nano-biological sensor which can respond to special analyte. one-dimensional (1d) nanomaterials (nanorods, nanobelts, nanotubes and nanowires) have drawn more attention particularly in view of physical and nano

10、apparatus applications. in the meantime, 1d semiconductor nanomaterials appears different optical properties, which have attracted more interest. the photoemission of cdse nanorods is highly polarized along the longer axis and surface-modified cdse/cds/zns core/shell qrs as a biological label can be

11、 used in a variety of bioimaging applications. furthermore, for single molecule fluorescence imaging, they are much brighter than qds. recently the syntheses of 1d semiconductor nanomaterial have been widely reported. however, the synthesis of 1d semiconductor nanotube was rarely researched.it is we

12、ll known that cyanine is a kind of fluorescence dye which modulated the wavelength of abortion and emission by alter the length of conjugated chain. cy-5 is the member of the family which has an absorption band centered at 600 nm. the fluorescence resonance energy transfer (fret) process is highly e

13、fficient when there is an appreciable overlap between the emission spectrum of the cdte qds donor and the absorption spectrum of the cy-5 acceptor. thus,fret is widely used for the research in molecule structures, properties, reaction mechanism and quantitative analysis. dna was carried out catalyti

14、c functions, and thus became the newest member of the enzyme family after proteins and rna. metal ion as cofactor increased the active of dnazyme. utilizing the property, appropriate dna chain by in-vitro selection can be used to direct metal ion.in this study, reviews were given on the application

15、of qds in multiplexed biological detection, the synthetic methods and the potential biological application of semiconductor materials with hollow nanostructures, and the detection of metal ions by dnazyme. on the bases of mentioned above, we carried out two aspects of investigation: 1, high aspect r

16、atio cdte nanostructures were fabricated by hierarchical assembly of nanoparticles at the wateroil interface. the new method overcomes the disadvantages of traditional organic synthesis. in addention, we investigated the effect of several factors, including reaction temperature, reaction time, addit

17、ional components, and reactant ratio. finally, optimal synthesis conditions have been chosed in research. 2, a new nanobiosensor qds-dnazyme-cy.5 was assembled for the direct determination of copper ions (cu2+) based on the fluorescence resonance energy transfer (fret) between cdte qds and cy.5. the

18、 sensing mechanism is based on the switching off fret through the high specific recognition of dnazyme to copper ions. in the absence of copper ions, cy.5 as excellent fluorescent acceptor in cdte-qds-dnazyme-cy.5 composites. fret switches off by the factor of copper ions-induced strand breaks in dnazym