层层自组装纳米金与乙酰胆碱酯酶电化学生物传感器检测有机磷农药

采用层层自组装技术制备了快速检测有机磷农药的生物传感器,利用带正电荷的高分子聚电解质聚二烯丙基二甲基氯化铵(PDDA)将乙酰胆碱酯酶(AChE)和金纳米粒子(AuNPs)通过静电力逐层固定到玻碳电极(GCE)表面,并采用交流阻抗和微分脉冲伏安法研究了此生物传感器的电化学行为。由于金纳米粒子优异的电催化性能和良好的生物相容性,使固定化的乙酰胆碱酯酶对其底物具有更高的亲和力和更快的响应速度。实验结果表明:修饰金纳米粒子后,传感器的氧化电流明显增大,在4.6×10-5～5.3×10-3mol/L范围内,固定化酶的抑制率与甲基对硫磷浓度的对数成正比,检出限为7.6×10-6mol/L。该生物传感器具有制备方法简便、成本低、灵敏度高等优点,已成功用于蔬菜样品中甲基对硫磷含量的测定。     

基于修饰石墨烯/纳米金复合膜固定乙酰胆碱酯酶的敌百虫传感器

结合氨基功能化离子液体修饰石墨烯(IL-GR)、纳米金(Au)等纳米材料的独特性质,以壳聚糖(CHIT)为交联剂,首先在玻碳电极表面固定IL-GR,然后吸附胶体金制得Au/IL-GR-CHIT复合膜,最后固定乙酰胆碱酯酶(AChE)制得新型有机磷检测酶传感器(AChE/Au/IL-GR-CHIT/GCE),并用于白菜样品中敌百虫农药的测定。采用透射电镜(TEM)对纳米材料进行了表征,循环伏安法(CV)和差示脉冲伏安法(DPV)研究了传感器的电化学性质。纳米复合物不仅为保持AChE的生物活性提供了适宜的微环境,并且对传感器性能的改善显示出强大的协同效应。在优化实验条件下,抑制率(A)与敌百虫浓度的负对数在2.0×10-10~1.0×10-6mol/L范围内呈良好的线性关系,检出限(S/N=3)为2.1×10-12mol/L。用于蔬菜中敌百虫含量的测定,回收率为97.5%~107.2%。     

再生丝素固定乙酰胆碱酯酶生物传感器

再生丝素固定乙酰胆碱酯酶生物传感器;生物传感器;乙酰胆碱酯酶;再生丝素     

基于乙酰胆碱酯酶抑制的有机磷农药生物传感器研究进展

有机磷农药(OPs)残留可通过食物链在生物体内富集,从而对自然生态和人类健康带来极大威胁.用于检测有机磷农药的传统分析方法(如高效液相色谱法和气相色谱法)具有响应时间较长、成本较高以及检测程序复杂等局限.近年来,生物传感因具有专一性强、速度快、准确度高等优势被广泛用于分析领域.而利用乙酰胆碱酯酶(AChE)作为识别元件...     

双重信号放大的乙酰胆碱酯酶电化学传感器检测有机磷农药

基于生物催化纳米金的生成和纳米金粒子电催化银沉积实现两次信号放大的原理,构建了一种快速、灵敏的乙酰胆碱酯酶电化学传感器,用于检测有机磷农药。固定在金电极表面的乙酰胆碱酯酶催化底物氯化乙酰硫代胆碱产生硫代胆碱,硫代胆碱还原氯金酸生成纳米金,将电极置于1.0 mol/L NH3-2.0×10#3mol/L AgNO3的银增强液中,由于纳米金粒子的催化作用,在#0.10 V的电压下,银只会沉积在生成的纳米金表面,沉积银的量与生成的纳米金颗粒的数目成正比,通过线性扫描伏安法定量检测沉积的银。在0.1~1000μg/L范围内,乙酰胆碱酯酶的抑制剂马拉硫磷的浓度与银的溶出峰呈线性,线性方程为i pa=149.9-40.49lgC(r=0.9963),检出限为0.05μg/L。本方法极大地提高了传感器检测的灵敏度。将其应用于湘江水样中马拉硫磷的检测,回收率在95.5%~102.2%之间,结果满意。     

基于氧化锌纳米棒的乙酰胆碱酯酶生物传感器用于辛硫磷农药测定

以喷金的聚碳酸酯模板为工作电极,采用电沉积法从氯化锌和氯化钾溶液中制得氧化锌纳米棒.将沉积了氧化锌纳米棒的模板固定在打磨后的玻碳电极表面,并将模板溶解.再通过在氧化锌纳米棒修饰电极的表面直接固定乙酰胆碱酯酶,制备出乙酰胆碱酯酶生物传感器.自然晾干后,所得乙酰胆碱酯争氧化锌生物传感器用于辛硫磷农药的测定.试验结果表明:在含有0.5 mmol·L-1的巯基乙酰胆碱的PH 7.38磷酸盐缓冲溶液中,乙酰胆碱酯酶-氧化锌修饰电极的氧化峰电流显著提高,而再向其中加入酶抑制剂辛硫磷后,电流明显减小,在此基础上提出了一种高灵敏度的测定辛硫磷农药的方法.在优化的条件下,辛硫磷浓度在9.85 × 10-6～4.95×10-4mol·L-1之间,其浓度的对数与抑制率呈线性关系,检出限(3S/N)为5.99×10-6mol·L-1.     

基于碳纳米管修饰电极检测有机磷农药的生物传感器

报道了一种用于检测有机磷农药的安培型生物传感器,利用戊二醛交联法将乙酰胆碱酯酶和牛血清白蛋白固定在羧基化多壁碳纳米管修饰玻碳电极表面,制备了可应用于检测有机磷农药的新型生物传感器,并确定了最佳工作条件.该方法具有良好的重现性和回收率,当辛硫磷及氧化乐果的浓度分别在5.0×10-4～5.0×10-1 g/L和1.0×10-3～5.0×10-1 g/L范围内时,抑制率与其浓度的对数呈线性关系,检出限按抑制率为10%时的农药浓度计算,可分别达到3.6×10-4 g/L和5.9×10-4 g/L.     

基于铂/碳球的乙酰胆碱酯酶传感器在农药乐果检测中的应用研究

基于农药乐果对乙酰胆碱酯酶的抑制作用,构建生物传感器,实现了农药乐果的快速、高灵敏检测。合成了纳米材料铂/碳球(Pt/Cs),利用其比表面积大、导电性好的优势,构建乙酰胆碱酯酶(ACh E)传感器。铂/碳球修饰电极比裸电极的阻抗更低,峰电流增加了147.06%,说明该材料能很好地保持酶的催化活性。在最优实验条件下,用ACh E传感器检测农药乐果,在1.0×10~(-9)~1.0×10~(-6)g/L范围,乐果浓度的负对数与抑制率呈良好的线性关系,其检出限为7.3×10~(-12)g/L(按抑制率为10%计算)。对纺织品样品进行加标回收实验,测得回收率为86.2%~101.7%。     

Sol-Gel/AChE/GLU/GCE传感器的研制及其对番茄碱的测定

利用戊二醛(GLU)交联剂的作用和溶胶-凝胶(Sol-Gel)固定化酶方法,采用"三明治"夹心结构的方法制得了Sol-Gel/AChE/GLU/GCE结构乙酰胆碱酯酶(AChE)传感器.通过传感器对氯化乙酰硫代胆碱的测定对其电极响应机理进行了探究,计算了米氏常数.结果表明:该传感器在pH 7.0磷酸缓冲溶液中对氯化乙酰...     

基于乙酰胆碱酯酶生物传感平台的西维因检测

为给农药西维因检测提供一种新方法,根据西维因抑制乙酰胆碱酯酶活性的原理,以黑珍珠2000（BP2000）为乙酰胆碱酯酶的固定化材料,采用滴凃电极法构建了基于乙酰胆碱酯酶的西维因生物传感平台. 结果表明,固定在BP2000 上的乙酰胆碱酯酶保持了对氯化乙酰胆碱的催化活性,并且由于BP2000 材料的引入,提升了电极有效的电化学活性表面积,而且电极上物质的电化学氧化拥有较低氧化电位（0.630 V）并伴随质子传输. 由BP2000 搭建成功的乙酰胆碱酯酶生物传感平台对西维因检测的线性响应范围为2.0 ng·mL^-1 ~ 12.5 ng·mL^-1,检测限为3.15 ng·mL^-1. 本研究对酶生物传感平台和酶生物燃料电池体系中酶电极的构建提供了一种简单方法及高效载体.     

Acetylcholinesterase Sensor with Patterned Structure for Detecting Organophosphorus Pesticides Based on Titanium Dioxide Sol‐gel Carrier

In this paper, novel and stable acetylcholinesterase (AChE) sensor with patterned structure for detecting organophosphorus pesticides (OPs) based on titanium dioxide sol‐gel carrier was proposed and prepared. Biosensor was assembled by dropping titanium oxide, chitosan (CS) and enzyme to the surface of the glass carbon step by step. The concentration range of the sensor detection for dichlorvos (DDVP) is 1.13 nM to 22.6 μM, and the limit of detection (LOD) is 0.23 nM. It can also detect dichlorvos in cabbage juice samples accurately. The preparation of biosensor adopted a patterned novel structure for the first time, which opens a new way for the structure optimization of organophosphorus pesticide sensor.     

Study of Inhibition,Reactivation and Aging Processes of Pesticides Using Graphene Nanosheets/Gold Nanoparticles‐Based Acetylcholinesterase Biosensor

Organophosphate (OP) and carbamate pesticides exert their toxicity via attacking the hydroxyl moiety of serine in the ‘active site’ of acetylcholinesterase (AChE). In this paper we developed a stable AChE biosensor based on self‐assembling AChE to graphene nanosheet (GN)‐gold nanoparticles (AuNPs) nanocomposite electrode for investigation of inhibition, reactivation and aging processes of different pesticides. It is confirmed that pesticides can inhibit AChE in a short time. OPs poisoning is treatable with oximes while carbarmates exposure is insensitive to oximes. The proposed electrochemical approach thus provides a new simple tool for comparison of pesticide sensitivity and guide of therapeutic intervention.     

Amperometric Biosensor Based on Immobilization Acetylcholinesterase on Manganese Porphyrin Nanoparticles for Detection of Trichlorfon with Flow‐Injection Analysis System

A highly sensitive amperometric biosensor for the detection of organophosphate pesticides (OPs) is developed. The biosensor was fabricated by immobilized acetylcholinesterase (AChE) on manganese (III) meso‐tetraphenylporphyrin (MnTPP) nanoparticles (NPs)‐modified glassy carbon (GC) electrode. The MnTPP NPs used in this article were synthesized by mixing solvent techniques. AChE enzyme was immobilized on the MnTPP NPs surface by conjugated with chitosan (CHIT). The electrocatalytic activity of MnTPP NPs led to a greatly improved performance for thiocholine (TCh) product detection. The developed AChE‐CHIT/MnTPPNP/GC biosensor integrated with a flow‐injection analysis (FIA) system was used to monitor trichlorfon (typical OP). A wide linear inhibition response for trichlorfon is observed in the range of 1.0 nM–1.0 mM, corresponding to 10–83% inhibition for AChE with a detection limit of 0.5 nM.     

利用溶胶-凝胶生物传感器测定饱和苯系物废水中酚类化合物

研制了用溶胶-凝胶包埋酪氨酸酶碳糊生物电极。其生物电极的工作条件为:电位为-100mV(vs.SCE),溶液pH5.40,响应时间为3min。本文方法对苯酚的检出限为1.00×10-6mol/L,线性范围为1.00×10-6~1.00×10-4mol/L,相对标准偏差为1.04%。实验结果表明,本电极对邻甲酚、对苯二酚、邻苯二酚、对氯苯酚都有良好的响应,但对邻氨基酚、间苯二酚、对甲苯酚、邻硝基酚、2.4二甲基酚响应较差。用本法对化工废水中酚类进行了测定,有机干扰物苯、甲苯、二甲苯对测定结果无影响。     

A Penicillamine Biosensor Based on Tyrosinase Immobilized on Nano‐Au/ PAMAM Dendrimer Modified Gold Electrode

Gold electrodes were modified with submonolayers of 3‐mercaptopropionic acid and further reacted with poly(amidoamine) (PAMAM) dendrimers to obtain thin films. The high affinity of PAMAM dendrimer for nano‐Au with its amine groups was used to realize the role of nano‐Au as an intermediator to immobilize the enzyme of tyrosinase. The characterization of the modified electrode was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and atomic force microscopy (AFM). Tyrosinase can catalyze the oxidation of catechol to o‐benzoquinone. When penicillamine was added to the solution, it reacted with o‐benzoquinone to form the corresponding thioquinone derivatives, which resulted in decrease of the reduction current of o‐benzoquinone. Based on this, a new electrochemical sensor for determination of penicillamine has been developed.     

利用流动注射型乙酰胆碱酯酶传感器监测海水中马拉硫磷

将乙酰胆碱酯酶(AChE)传感器引入流动注射系统中，研究了传感器连续监测海水中马拉硫磷的可行性。系统中的载液为不含马拉硫磷的海水。传感器适宜的工作条件为：载液和样品的流速为0．39mL／min，进样时间为20min；底物(碘化硫代乙酰胆碱)溶液的浓度为41．6mmol／L，注射量为40μL。利用次氯酸钠溶液对含马拉硫磷的海水样品进行预氧化处理，可以大大提高传感器的灵敏度，对马拉硫磷的检出限达到0．05μg/L；而不进行氧化时的检出限为1．3μg/L。另外，海水样品经过预氧化处理后，传感器对其中0．1-10μg／L的马拉硫磷具有良好的线性响应关系(r=0．991)。测定含马拉硫磷的海水样品后，向传感器持续通入0．5mmol／L的2-PAM溶液15min，可以完全恢复受到100μg／L马拉硫磷抑制的固定化酶活性。结果表明：所设计的酶传感器适于海水中马拉硫磷的连续、灵敏和准确监测。     

Determination of Organophosphorus Pesticides Based on BDD Electrode Modified with Au/chitosan Fiber

The Au/chitosan fiber was firstly prepared by electrospinning and chemical reduction method and used to modify BDD electrode for the detection of methyl parathion. The results indicated that Au/chitosan fiber‐modified BDD electrode could improve the electrocatalytic activity, accelerate response, enhance the sensitivity, and reduce the detection limit, as compared with the bare BDD electrode. The repeatability and stability of Au/chitosan fiber‐modified BDD electrode was also studied. For the detection of methyl parathion in the apple juice samples, Au/chitosan fiber‐modified BDD electrode obtained favorable results and ideal recovery rate.     

Determination of Catechol by a Laccase Biosensor Based on Silica-Modified Zirconia Nanoparticles

A promising nanotechnological material, zirconia nanoparticles modified with SiO₂, was used as a medium for the immobilization of laccase to construct a novel biosensor that exhibits sensitive amperometric response to catechol in 0.1 mol · L^?1 phosphate buffer (pH 6.0) using cyclic voltammetry. The linear response to catechol was from 1.0 × 10^?6 to 1.0 × 10^?4 mol · L^?1 and the detection limit was 3.5 × 10^?7 mol · L^?1 at a signal-to-noise ratio of 3. The biosensor exhibited good stability, precision, and few interferences.     

Spectrophotomeric Assay of Aflatoxin B1 Using Acetylcholinesterase Immobilized on Standard Microplates

Aflatoxins are a group of hepatotoxic secondary metabolites produced by molds Aspergillus. During inappropriate storage or processing of food and beverages, aflatoxins can be distributed and become a serious health problem. Disparate analytical techniques were prepared for the assay in the past. Here, a method based on inhibition of enzyme acetylcholinesterase (AChE) is performed allowing fast and simple prove of aflatoxins presence. For the assay purposes, AChE was immobilized on standard polystyrene microplates using gelatin as a stabilizing substance. Both free and immobilized AChEs were used and compared one to each other. Immobilization protocol was optimized and interference of organic solvents such as methanol was tested. For the immobilized AChE, limit of detection 2.75 ppb for aflatoxin B1 was received. The immobilized AChE kept full activity at least one month. Suitability of the assay for a practical performance is considered.