基于碳纳米管修饰的DNA电化学传感器用于大肠杆菌基因片段检测

利用全氟代磺酸脂(Nafion)的成膜效应将多壁碳纳米管(MWCNTs)固定在玻碳电极(GCE)上,制得MWCNTs/Nafion/GCE修饰电极。利用MWCNTs上的羧基和大肠杆菌DNA探针上修饰的氨基之间的酰化反应将探针固定在电极上,大肠杆菌目标DNA与固定于电极表面的DNA探针杂交后,电极表面的电子传递电阻变大,从而实现大肠杆菌目标DNA基因片段的测定。通过电化学循环伏安法(CV)和交流阻抗法(EIS)对所制备的传感器的灵敏度和选择性进行表征,在优化条件下,检测大肠杆菌基因片段的线性范围为10 pmol/L～1.0μmol/L,检出限为6.3 pmol/L,相关系数R~2=0.9965。     

基于纳米ZnO/壳聚糖复合膜DNA电化学传感器用于HIV基因的免标记检测

以室温固相合成法制备纳米ZnO,通过壳聚糖(CHIT)的成膜效应将纳米ZnO固定在玻碳电极(GCE)表面,制得的ZnO/CHIT/GCE电极成为DNA固定和杂交的良好平台。DNA的固定和杂交通过电化学交流阻抗进行表征。以电化学交流阻抗免标记法检测目标DNA,固定于电极表面的DNA探针与目标DNA杂交后使电极表面的电子传递电阻增大,以此作为检测信号可以高灵敏度地测定目标DNA。电化学阻抗谱检测人类免疫缺陷病毒(HIV)基因片段的线性范围为2.0×10-11~2.0×10-6mol/L,检出限为2.0×10-12mol/L。     

一种新型电化学DNA生物传感器的制备

将金纳米粒子(Au NPs)负载到氮掺杂石墨烯(N-G)的表面,用来修饰玻碳电极(GCE);以亚甲基蓝(MB)为指示剂,将探针DNA连接在电极表面,成功构建了DNA传感器。通过交流阻抗曲线(EIS)和差分脉冲曲线(DPV)的变化探讨了该传感器的选择性,重复性。得到了该电化学传感器的检测限为1.034×10~(-9)mol/L。     

基于不同电化学探针检测乳腺癌基因片段电化学传感器的研究

构建了以3种不同电活性物质(铁氰化钾平衡电对、亚甲基蓝和六氨合钌)为电化学信号探针,检测乳腺癌基因片段(乳腺癌DNA)的电化学传感器。利用吸附作用将探针ss DNA固定于金纳米-多壁碳纳米管-Nafion复合纳米材料修饰金电极表面,制备了DNA电化学传感器。采用循环伏安法、电化学阻抗法和微分脉冲伏安法,对DNA电化学传感器进行表征和定量分析。实验结果表明,在5 mmol/L K3[Fe(CN)6]-5mmol/L K4[Fe(CN)6]平衡电对电化学探针检测液中,乳腺癌DNA的线性范围为0.1~500.0 nmol/L,其检出限(S/N=3)为0.03 nmol/L。以20μmol/L亚甲基蓝为电化学探针检测液时,乳腺癌DNA的线性范围为1.0~500.0 nmol/L,检出限为0.3 nmol/L。利用50μmol/L六氨合钌电化学探针检测时,乳腺癌DNA的线性范围为1.0~500.0 nmol/L,检出限为0.3 nmol/L。3种电化学探针中,利用铁氰化钾平衡电对探针检测乳腺癌DNA的检出限最低,线性范围最宽。该传感器可用于其他DNA的检测分析。     

基于纳米MnO2的免标记型DNA电化学生物传感器用于大肠杆菌的测定

以室温固相合成法制备纳米MnO2,通过壳聚糖（CHIT）的成膜效应将纳米MnO2固定在玻碳电极表面。DNA在MnO2/CHIT膜上的固定和杂交通过循环伏安和电化学交流阻抗进行表征。以电化学阻抗免标记法检测目标DNA,固定于电极表面的DNA探针与目标DNA杂交后使电极表面的电子传递电阻增大,以此作为检测信号可以高灵敏度地测定目标DNA。电化学阻抗谱检测大肠杆菌基因片段的线性范围为2.0×10^-11 ～2.0×10^-6mol/L,检出限为1.0×10^-12mol/L。     

检测急性早幼粒细胞白血病PML-RARα融合基因的DNA传感器研制

利用共价键合法,将氨基修饰的具有急性早幼粒细胞白血病PML-RARα融合基因特异性的单链DNA探针固定在玻碳电极表面,构成急性早幼粒细胞白血病DNA传感器 (急粒DNA传感器).以电活性的芦荟大黄素(AE)为杂交指示剂,考察了杂交温度及传感器的特异性、重现性和检出限等性能.结果表明:AE在裸电极上的吸附常数为(4.5±0.2)×105 L·5mol-1,与单链DNA修饰的玻碳电极(ssDNA/GCE)和双链DNA修饰的玻碳电极(dsDNA/GCE)结合常数分别为(2.1±0.4)×105和(2.7±0.2)×105 L·5mol-1.这种新型的DNA传感器具有特异性强、灵敏度高和重现性好的优点.应用此方法于临床血清分析,初步探索了将该法应用于临床检测的可行性.     

尼泊金乙酯分子印迹膜电化学传感器的制备

以邻苯二胺为功能单体,尼泊金乙酯为模板分子,通过电化学聚合在玻碳电极表面制备了尼泊金乙酯分子印迹膜,采用循环伏安法及方波伏安法,以K3[Fe(CN)6]为电活性探针,建立了间接测定尼泊金乙酯的分析方法。实验结果表明,制备的分子印迹膜电化学传感器对尼泊金乙酯具有较高的选择性和灵敏度,测定尼泊金乙脂的线性范围为2.5×10-6~1.0×10-5 mol/L,检出限为8.61×10-8 mol/L。     

基于金纳米粒子/聚阿魏酸/多壁碳纳米管修饰电极的DNA计时库仑法生物传感器的制备

构建了基于金纳米粒子/聚阿魏酸/多壁碳纳米管(AuNPs/PFA/MWCNTs)修饰电极的DNA计时库仑法生物传感器.利用循环伏安技术在多壁碳管修饰的玻碳电极表面上聚合一层阿魏酸,在恒电位条件下,在阿魏酸表面沉积金纳米粒子,巯基DNA作为探针通过金硫键固定在金纳米粒子表面.电化学交流阻抗技术(EIS)与扫描电镜(SEM...     

基于多边形金纳米颗粒的非标记型可卡因适体传感器的研制

实验合成了多边形金纳米颗粒,通过壳聚糖(CHIT)将合成的多边形金纳米颗粒固定在玻碳电极表面,然后通过自组装技术将带巯基的捕获DNA探针固定在修饰有多边形金纳米颗粒的电极表面,利用杂交反应使可卡因适体与DNA捕获探针结合,制成非标记型可卡因适体传感器。以六氨合钌作为电化学指示剂,通过测量传感器与目标物可卡因结合前后电流变化情况对可卡因进行测定。考察了缓冲溶液的pH、可卡因培育时间、扫描速度等对测定的影响。结果表明,在pH为7.40时该传感器的检测范围为1.0×10-10～1.0×10-3 mol/L,检测限为3.0×10-11 mol/L。该传感器制作简单,响应好,抗干扰能力强。     

聚亚甲基蓝和纳米金修饰玻碳电极的葡萄糖生物传感器

用循环伏安法在玻碳电极上电聚合一层稳定的亚甲蓝聚合物膜,研究了这层膜在0.1mol/L磷酸缓冲溶液(pH7.0)中的电化学性质。用纳米金溶胶与聚乙烯醇缩丁醛(PVB)构成复合固酶基质,采用溶胶-凝胶法固定葡萄糖氧化酶(GOD)于亚甲蓝修饰的玻碳电极表面,制成了新型葡萄糖生物传感器。实验发现,加入纳米金后提高了酶电极对葡萄糖的电流响应,所制备的传感器具有响应快、灵敏度高、稳定性好,对葡萄糖的线性响应范围为1×10-6~3×10-3mol/L,检出限为5×10-7mol/L。并具有抗尿酸、抗坏血酸干扰的特点。     

A PDDA/poly(2,6-pyridinedicarboxylic acid)-CNTs composite film DNA electrochemical sensor and its application for the detection of specific sequences related to PAT gene and NOS gene

2,6-Pyridinedicarboxylic acid (PDC) was electropolymerized on the glassy carbon electrode (GCE) surface combined with carboxylic group-functionalized single-walled carbon nanotubes (SWNTs) by cyclic voltammetry (CV) to form PDC-SWNTs composite film, which was rich in negatively charged carboxylic group. Then, poly(diallyldimethyl ammonium chloride) (PDDA), a linear cationic polyelectrolyte, was electrostatically adsorbed on the PDC-SWNTs/GCE surface. DNA probes with negatively charged phosphate group at the 5' end were immobilized on the PDDA/PDC-SWNTs/GCE due to the strong electrostatic attraction between PDDA and phosphate group of DNA. It has been found that modification of the electrode with PDC-SWNTs film has enhanced the effective electrode surface area and electron-transfer ability, in addition to providing negatively charged groups for the electrostatic assembly of cationic polyelectrolyte. PDDA plays a key role in the attachment of DNA probes to the PDC-SWNTs composite film and acts as a bridge to connect DNA with PDC-SWNTs film. The cathodic peak current of methylene blue (MB), an electroactive label, decreased obviously after the hybridization of DNA probe (ssDNA) with the complementary DNA (cDNA). This peak current change was used to monitor the recognition of the specific sequences related to PAT gene in the transgenic corn and the polymerase chain reaction (PCR) amplification of NOS gene from the sample of transgenic soybean with satisfactory results. Under optimal conditions, the dynamic detection range of the sensor to PAT gene target sequence was from 1.0x10(-11) to 1.0x10(-6) mol/L with the detection limit of 2.6x10(-12) mol/L.     

Highly Sensitive and Selective Amperometric Sensor for Iodate Based on 9,10-Phenanthrenequinone Derived Graphene

We reported on a new amperometric sensor for the sensitive and selective determination of iodate in table salt. The iodate sensor was constructed by the integration of a novel nanocomposite which was made from 9,10-phenanthrenequinone(PQ) and graphene(GP) with a glassy carbon electrode(GCE). The synthesized graphene and the nanocomposite were well characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), Fourier transform infrared(FTIR) spectroscopy and Raman spectroscopy. We fully studied the electrochemical behavior and kinetic characteristics of the PQ/GP nanocomposite at GCE. The PQ/GP electrode shows a good electrochemical catalytic activity towards the reduction of iodate, which makes itself a sensitive and selective electrochemical sensor for iodate. The iodate sensor displays a high sensitivity(1.04 mA·mmol·L^-1), a low detection limit(1.0×10^-8 mol/L), a rapid response(less than 2 s), and a broad linear range(from 5.0×10^-8 mol/L to 6.0×10^-3 mol/L ). In addition, the sensor is interference free. The practical application of the proposed sensor was tested by the detection of iodate in table salt.     

以还原氧化石墨烯和纳米二氧化锆为DNA探针固定平台电化学测定转基因玉米中特定基因序列

草胺膦乙酰转移酶基因(PAT)是一种转基因植物的外源DNA片段。 本文以还原氧化石墨烯和纳米二氧化锆(nanoZrO₂)的复合物作为固定DNA探针的平台,建立了一种灵敏地检测PAT基因的方法。 首先,氧化石墨烯直接在电极表面进行电化学还原,然后将一层nanoZrO₂涂覆于其表面,利用DNA中的磷酸基团与nanoZrO₂中氧的亲和作用固定DNA探针。 通过微分脉冲伏安法检测DNA探针与PAT基因片段的杂交,构建了用于检测PAT基因片段的电化学生物传感器。 该传感器具有稳定性好,重复性好的特点,可灵敏地检测转基因玉米中的PAT基因,检测限达2.0×10^-15 mol/L。     

用聚(L-蛋氨酸)/纳米金修饰玻碳电极同时灵敏检测多巴胺和尿酸简

A novel electrochemical sensor was fabricated by electrodeposition of gold nanoparticles on a poly(L-methionine) (PMT)-modified glassy carbon electrode (GCE) to form a nano-Au/PMT composite-modified GCE (nano-Au/PMT/GCE). Scanning electron microscopy and electrochemical techniques were used to characterize the composite electrode. The modified electrode exhibited considerable electrocatalytic activity towards the oxidation of dopamine (DA) and uric acid (UA) in phosphate buffer solution (pH = 7.00). Differential pulse voltammetry revealed that the electrocatalytic oxidation currents of DA and UA were linearly related to concentration over the range of 5.0×10^-8 to 10^-6 mol/L for DA and 7.0×10^-8 to 10^-6 mol/L for UA. The detection limits were 3.7×10^-8 mol/L for DA and 4.5×10^-8 mol/L for UA at a signal-to-noise ratio of 3. According to our experimental results, nano-Au/PMT/GCE can be used as a sensitive and selective sensor for simultaneous determination of DA and UA.     

盐酸普萘洛尔分子印迹电化学传感器的制备与研究

以盐酸普萘洛尔为目标模板分子,通过电聚合多巴胺,在多壁碳纳米管修饰的玻碳电极表面制备了对目标分子有特异响应的分子印迹电化学传感器.利用扫描电子显微镜、循环伏安法和差示脉冲伏安法对此传感器的表面形貌及性能进行了表征,并且优化了检测条件,研究了印迹传感器对模板分子及其结构类似物的选择性响应.结果表明:此传感器具有较好的选择性响应,而且碳纳米管的存在显著提高了传感器的灵敏度.盐酸普萘洛尔的浓度在0.20～100 μmol/L范围内与峰电流呈良好的线性关系;检出限为2.53×10-8 mol/L(S/N=3).此传感器还具有良好的稳定性和重现性.     

Electrochemical Determination of Phenylethanolamine A Based on Nafion/MWCNTs/AuNPs Modified Carbon Electrode

Phenylethanolamine A (PEA), a β‐agonist, was found to be illegally used as a growth promoter in pigs last year, causing Chinese government's great attention. Here, a sensitive electrochemical method was developed for detecting PEA by immobilization of gold nanoparticles (AuNPs), multiwalled carbon nanotubes (MWCNTs) and Nafion on the surface of a glassy carbon electrode (GCE). The Nafion/MWCNTs/AuNPs film was characterized by scanning electronic micrographs (SEM) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of PEA at the modified GCE were investigated in detail. The synergetic effects of AuNPs, MWCNTs and Nafion amplify the electrochemical reduction signal of PEA, and result in high sensitivity for PEA determination. Under the optimal conditions, the electrochemical sensor shows a wide linear range of 0.01 to 10 (mol/L with a detection limit of 0.005 µmol/L. Moreover, the fabricated sensor presents high selectivity and long‐term stability, which paves a new way for simple, rapid, sensitive detection of PEA.     

基于DNA电化学发光传感器研究金纳米颗粒对量子点的电化学发光影响

纳米金颗粒具有高的消光系数和良好的表面等离子体共振特性, 其等离子体共振特性受纳米金颗粒的尺寸和周围环境等因素的影响. 本文基于半导体纳米晶电化学发光信号对金纳米颗粒的距离依赖性制备了DNA电化学发光传感器. 首先利用循环伏安法(CV)在玻碳电极(GCE)表面原位沉积金纳米颗粒(AuNPs), 巯基丙酸包裹的CdS量子点(QDs)与氨基修饰的双链DNA (dsDNA)通过酰胺键缩合, 形成量子点修饰的双链DNA(QDs-dsDNA). 最后将QDs-dsDNA 通过dsDNA 另一端的巯基组装到纳米金表面, 得到CdS QDs-DNA/AuNPs/GCE电化学发光传感器. 在优化电极表面QDs-dsDNA密度、金纳米颗粒沉积方法等实验条件的基础上, 对不同传感器的表面性质进行了表征, 如形貌和电化学阻抗等. 进一步通过控制纳米金和CdS QDs之间的DNA研究了纳米金对CdS QDs发光信号的影响作用. 结果显示DNA链的长度和类型对发光信号有着重要的影响. 最后将此传感器用于环境污染物的DNA损伤检测, 显示出很好的灵敏响应.     

Electrochemical sensing of DNA immobilization and hybridization based on carbon nanotubes/nano zinc oxide/chitosan composite film

A novel electrochemical DNA biosensor based on zinc oxide （ZnO） nanoparticles and multi-walled carbon nanotubes （MWNTs） for DNA immobilization and enhanced hybridization detection is presented. The MWNTs/nano ZnO/chitosan composite film modified glassy carbon electrode （MWNTs/ZnO/CHIT/GCE） was fabricated and DNA probes were immobilized on the electrode surface. The hybridization events were monitored by differential pulse voltammetry （DPV） using methylene blue （MB） as an indicator. The sensor can effectively discriminate different DNA sequences related to PAT gene in the transgenic corn, with a detection limit of 2.8× 10^-12 mol/L of target sequence.     

脉冲恒电位一步法制备聚3,4-乙烯二氧噻吩石墨烯复合材料构建无酶葡萄糖传感器

本研究利用石墨烯(rGO)与3,4-乙烯二氧噻吩(EDOT)单体芳香环之间的π-π*相互作用和氢键作用,采用脉冲恒电位一步法制备了聚3,4-乙烯二氧噻吩石墨烯(PEDOT-rGO)复合膜,将纳米镍(NiNPs)电沉积在此复合膜(PEDOT-rGO)表面,制备了NiNPs/PEDOT-rGO修饰玻碳电极(NiNPs/PEDOT-rGO/GCE),研究了此修饰电极对葡萄糖的电催化氧化性能.实验结果表明,此NiNPs/PEDOT-rGO/GCE可以作为无酶传感器实现对葡萄糖的检测.本方法稳定性高,选择性好,线性范围宽(2μmol/L~58 mmol/L),检出限低至0.7μmol/L,可以用于对葡萄糖的快速、灵敏检测.