發(fā)布時間：2018-03-01 05:31

  本文關鍵詞： 持久性有機污染物 電化學傳感器 環(huán)糊精 核酸適體 納米材料 石墨烯 碳納米管 金納米顆粒　出處：《湖南大學》2015年碩士論文　論文類型：學位論文

【摘要】：持久性有機污染物(Persistent organic pollutants,POPs)是一類具有高毒、持久、生物積累性、遠距離遷移性,嚴重危害人類健康和環(huán)境的人工合成的有機污染物。POPs大多具有致癌、致畸、致突變效應和遺傳毒性,能干擾人體內分泌系統(tǒng),并且廣泛存在于全球范圍內各種環(huán)境介質以及動植物組織器官和人體中,已經成為一個新的全球性問題。因此,發(fā)展高靈敏、高選擇性的傳感器痕量檢測POPs刻不容緩。β-環(huán)糊精(β-cyclodextrin,β-CD)是由環(huán)糊精葡萄糖殘基酶作用于葡萄糖聚合物形成的寡聚葡萄糖,由7個D-吡喃葡萄糖基以α-1,4葡萄糖苷鍵連接而成。β-環(huán)糊精可依據(jù)范德華力、疏水相互作用力、主客體分子間的匹配作用與許多無機、有機分子、無機離子結合成主客體包合物。核酸適體(簡稱“適體”,aptamer)是能特異結合蛋白質或其他小分子物質的寡聚核苷酸片段。適體作為一種新的識別分子,適體對靶分子有高度親和力和嚴格特異性識別能力,因而適體生物傳感器往往具有好的靈敏度和高選擇性。利用環(huán)糊精或核酸適體特異性結合環(huán)境中痕量的污染物,并協(xié)同納米材料(石墨烯、碳納米管、多孔碳材料、金納米顆粒)優(yōu)異的物理、化學性能,本文制備了一系列電化學傳感器,用于超靈敏檢測POPs:(1)采用六亞甲基二異氰酸酯(HMDI)作為交聯(lián)劑聚合β-CD,制備了β-CD-HMDI聚合物非共價功能化多壁碳納米管(MWCNTs/Poly(β-CD-HMDI)復合材料,并采用傅里葉紅外、X射線衍射法、掃描電鏡、熱重分析和電化學方法對其表征�；贛WCNTs/Poly(β-CD-HMDI)復合材料,成功地制備了一種新型電化學傳感器,用于檢測非電活性4,4’-二氯聯(lián)苯(DPCB)。研究中以中性紅(NR)做探針,由于主客體包合作用,NR進入環(huán)糊精空腔,在MWCNTs/Poly(β-CD-HMDI)/GC電極上出現(xiàn)明顯的NR峰電流。由于環(huán)糊精對探針分子和目標分子的包合作用存在競爭關系,當DPCB存在時,DPCB分子取代NR分子,從而導致NR的峰電流下降。利用NR的峰信號變化,實現(xiàn)對DPCB的間接電化學檢測。所制備的MWCNTs/Poly(β-CD-HMDI)/GCE電化學傳感器具有好的靈敏度、重現(xiàn)性和穩(wěn)定性,檢測線性范圍為2 nM～80 uM,檢測限為0.4 nM(S/N=3)。(2)基于探針分子羅丹明B(Rh B)和目標分子雙酚A(BPA)與電聚合β-環(huán)糊精/電還原石墨烯(Pβ-CD/EG)的主客體競爭包合作用,建立了一種新型電流比電化學傳感器用于高靈敏檢測雙酚A。Rh B進入β-CD疏水內腔,在Pβ-CD/EG修飾玻碳電極上出現(xiàn)明顯的氧化峰電流。雙酚A存在時,與Rh B相比,BPA與β-CD的主客體結合能力更強,Rh B被BPA取代。因此,Rh B峰電流(IRh B)下降,BPA峰電流(I_(BPA))相應增加。在1～6000 nM濃度范圍內,電流比I_(BPA)/IRh B與BPA濃度呈線性關系,檢測限為52 pM(S/N=3)。本方案用于高靈敏度檢測BPA,有望在實際環(huán)境樣中檢測有機污染物。(3)基于適體與目標分子BPA的特異性結合作用,制備了一種新型雙信號電化學生物傳感器,實現(xiàn)對BPA的高選擇性、超靈敏檢測。首先,在電極表面電沉金納米顆粒(Au NPs),然后將適體DNA(DNA1)和與之互補的DNA鏈(c DNA)雜交的雙鏈DNA自組裝到電極表面,c DNA上標記有亞甲基藍(MB),因而在電極上出現(xiàn)較強的MB電信號。當存在BPA目標分子時,適體與BPA結合,修飾有MB的c DNA會從雙鏈DNA中解離出來,導致MB的電信號減弱,與此同時電極上出現(xiàn)BPA的電信號。本方案用于高靈敏度、高選擇性檢測BPA,在1 pM～100 nM濃度范圍內,I_(BPA)/I_(MB)與BPA濃度呈線性關系,檢測限為0.09 pM(S/N=3),有望用于實際環(huán)境樣中有機污染物的檢測。
[Abstract]:Persistent organic pollutants (Persistent organic, pollutants, POPs) is a kind of high toxicity, persistence, bioaccumulation, long-range transport of organic pollutants,.POPs synthetic serious harm to human health and the environment are carcinogenic, teratogenic, mutagenic effects and genetic toxicity, can interfere with the body's endocrine system, and widely exists in the various environmental media worldwide and the tissues of plants and animals and humans, has become a new global problem. Therefore, the development of high sensitive, high selective sensor POPs trace detection delay. B-cyclodextrin (beta beta -cyclodextrin, -CD) is formed by cyclodextrin glucosyl residues of enzymes in glucose polymer oligomeric glucose by 7 D- glycosyl to alpha -1,4 glucoside linkages and beta cyclodextrin. On the basis of Fan Dehua force, hydrophobic interaction, host guest molecule The match between many inorganic, organic molecules, inorganic ions to form host guest inclusion complexes. The aptamer (referred to as "aptamer", aptamer) is the specific binding to proteins or other small molecules oligonucleotides aptamer. As a new kind of molecular recognition, the aptamer with high affinity strict and specific recognition ability to the target molecule, so the aptamer biosensor has good sensitivity and high selectivity. The use of cyclodextrin or aptamer binding specificity of trace contaminants in the environment, and the coordination of nano materials (graphite, carbon nanotubes, porous carbon materials, gold nanoparticles) excellent physical and the chemical properties, a series of electrochemical sensors were prepared for ultrasensitive detection of POPs: (1) with six methylene diisocyanate (HMDI) as crosslinking agent was prepared by polymerization of beta -CD and beta -CD-HMDI polymer non covalently functionalized multi walled carbon Nanotubes (MWCNTs/Poly (beta -CD-HMDI) composite materials, and using Fourier transform infrared, X ray diffraction, scanning electron microscopy, thermogravimetric analysis and electrochemical method for its characterization. Based on the MWCNTs/Poly (beta -CD-HMDI) composites were successfully prepared by a novel electrochemical sensor, for the detection of non electric activity of 4,4 '- two chlorodiphenyl (DPCB). In order to study the neutral red (NR) as probe, the host guest inclusion, NR into the cavity of cyclodextrin, MWCNTs/Poly (beta -CD-HMDI) NR peak current appeared on /GC electrode. Because there is competition between the cyclodextrin and the probe molecule target molecule inclusion, when DPCB when DPCB molecules replace NR molecules, resulting in the peak current of NR decreased. The change peak signal of NR, realize the indirect electrochemical detection for DPCB expression. The prepared MWCNTs/Poly (beta -CD-HMDI) /GCE electrochemical sensor has good sensitivity and reproducibility. 紼沖畾鎬，

本文編號：1550649