石墨烯三维微电极生物传感器研究

基于石墨烯优良的导电性和透明性,为改善生物传感器存在透明性不足的缺陷,提出了石墨烯三维微电极传感器的研究.利用SEM,Raman对其形貌进行表征,以及采用电化学测试电极电化学性能,结果表明:研究的石墨烯三维电极生物传感器在透明性和电化学性能方面优于传统微电极生物传感器,为透明生物传感器的制作提供了新思路.     

血药测定仪

血药浓度的检测能指导临床治疗,从经验性治疗转向科学性治疗,此项工作的开展能减少药物毒副作用的危险,防止毒效发生,要想开展好这项工作,必需具有科学的测试手段,目前已有一些仪器和方法:放射免疫法、火焰光度法、离子选择性电极、生物电化学传感器、离子敏传感器及微生物传感器等,本章重点讨论离子选择电极、生物电化学传感器、离子敏传感器在血液检测中所发挥的功能。     

植物组织电极

离子选择电极是六十年代后期以来发展最迅速的分析技术之一。在离子选择性原电极表面固定一层具有分子识别功能的酶、抗原或抗体、激素、微生物及某些生物细胞和组织,即可构成以电化学信号为基础的电极型生物传感器。此领域的研究近年来已成为化学工作者聚集的“热点”之一。国际性专业杂志“Biosensors”已于1985年创刊,每年公开报导的文献已达400余篇。根据美国教授Rechnitz用玻璃电极为主干以生物形象的“家谱树”图所比喻总结的电化学膜电极概貌,组织电极位于其图中的枝叶繁茂之处,有着旺     

发明与专利

一种检测多巴胺的电化学生物传感器及其制备方法 【摘要】本发明公开了一种检测多巴胺的电化学生物传感器及其制备方法,该生物传感器是先采用电化学方法在铂盘电极表面电聚合包覆一层聚（3,4-乙烯二氧噻吩）薄膜,然后通过静电作用与纳米金结合而得。该生物传感器具有超强的稳定寿命,     

微型电流式生物传感器

1967年 Updike 和 Hick 根据 Clark 等人提出的酶和电极相结合测定酶底物的原理,应用酶固定化技术研制出世界上第一支以氧电极为基础的葡萄糖传感器,开拓了一个新的生物传感器研究领域。其后相继发展出组织、微生物、免疫和细胞等生物传感器。其中基于电化学原理进行测定的生物电化学传感器是生物传感器的一个重要分支。依据生物电化学传感器电信号测定方式的不同,一般可分为电流式、电位式和电导式三类,电流式和电位式占主导地位。电流式电化学生物传感器的基础电极一般是 O_2、H_2O_2、H_2电极。现已经研制出多种不同的电流式生物传感器,且许多已商品化,广泛地应用在国民经济各个领域,许多学者作了这方面的详细综述。     

基于纳米材料的辣根过氧化物酶电化学传感器的构建

酶生物传感器具有高选择性是由于酶对底物高选择性和反应产物指示无干扰性.这为在大量常规分析中进行快速实时分析提供了可能.自从Clark等首次报道了可以将酶固定在电化学检测器表面制成酶电极以来,电化学生物传感器得到了迅速地发展,电化学传感器被认为是21世纪最具有前途的研究领域之一.     

壳聚糖修饰电极的电化学行为及其在生物传感器中的应用

该文利用循环伏安法考察了尿酸、抗坏血酸在壳聚糖修饰电极上的电化学行为.实验结果表明,不同浓度的壳聚糖修饰电极的电化学性能有所不同.通过系统的实验摸索,确定壳聚糖修饰液浓度以5mg/mL为佳.利用壳聚糖作为固膜基质制作生物传感器,方法简便,制得的电极对葡萄糖响应讯速,一般几秒内就达到稳定的电流,抗干扰性能也有了明显的提高,有望在专一性更强、灵敏度更高的第三代生物传感器的制作中得以进一步应用.     

Au—Ni／酪氨酸酶修饰生物传感器检定BPA

将镍金材料结合壳聚糖修饰于玻碳电极表面形成复合膜,酪氨酸酶（Tyr）借助NHS～EDC联酶法修饰于复合膜上,制备了一种新型的酪氨酸酶修饰电极。以循环伏安法和电化学阻抗谱实验研究了修饰电极的电化学性能。由于复合材料良好的生物相容性和高电导特性,联酶法保持了酶活性和稳定性,该传感器对双酚A（BPA）具有良好的电化学响应。在最佳实验条件下,该传感器对双酚A的检测范围为：4．0×10^-8～5．0×10^-6mol／L,检测限为1.0×10^-8mol／L（信噪比=3）。该传感器具有良好的性能,重现性,稳定性。     

修饰电极在流动体系电化学检测器中的应用与发展

本文总结电化学修饰电极、激光脉冲修饰电极、金属氧化物修饰电极、化学修饰电极、生物修饰电极在液相色谱(LC)和流动注射分析(FIA)中的应用和发展。     

介质电流型电极的作用机制探讨

生物传感器以其生物活性分子识别作为基础,有严格的专一性、较高的灵敏度,且操作方便简单,在生物过程控制和医疗临床上有广泛的应用前景,因此,新型生物传感器的开发研究日益受到重视。生物传感器由于其生物活性成分的不同(如酶、细胞、细胞器、免疫物质、受体等)和传感方式的不同(如压电型、电流型、电压型、FET 型、光敏型、热敏型等)分成许多类型,但现在研究得最多,应用范围最广的是电流型酶生物传感器。自从1962年 Clark和 Lyons 第一次提出“酶电极”概念以来,这种生物传感器发展迅速,已经从传统的第一代二次传感型电极,经过第二代一次传感型电极(1984,Cass et al),发展到第三代直接传感电极三代传感器的作用原理图见图1.     

碳纳米管修饰酶生物传感器的应用进展

很多酶生物传感器是利用氧化酶将底物氧化,同时产生过氧化氢,通过在电极表面检测过氧化氢的量来达到检测的目的。碳纳米管用于修饰电极,可降低化学物质氧化还原反应的过电位,改善生物分子氧化还原可逆性,达到提高检测的灵敏度和稳定性的目的。本文介绍了酶生物传感器及碳纳米管修饰酶生物传感器,并综述了近几年来碳纳米管修饰酶生物传感器的应用进展。     

Glycerol biosensor based on glycerol dehydrogenase incorporated into polyaniline modified aluminum electrode using hexacyanoferrate as mediator

Enzyme-modified electrodes were fabricated by the immobilization of glycerol dehyrogenase into the polyaniline film and were used as glycerol biosensors. Two different electrodes were prepared by forming monolayer and bilayer electroactive films on the electrode surface and were compared. Potassium ferrocyanide was used as mediator of the biosensing reaction. The biosensors exhibit amperometric response to the glycerol in the range 5×10⁻⁶ to 2×10⁻³ M with detection limit of 1×10⁻⁶ M. The Michaelis–Menten constants, K_m′, of the electrodes were calculated, their values indicates that the enzyme has not chemically modified with the electrode materials and has its original enzymatic activity. The electrode has a good stability and selectivity due to the enhanced stability of the deposited polyaniline film on Al substrate.     

Urea biosensors

A biosensor is an analytical tool that comprises two essential components—an immobilized biocomponent, in intimate contact with a transducer that converts a biological signal into a measurable electrical signal. This review summarizes the studies carried on the development of biosensors for the analysis of urea in different fields of application, the various techniques of immobilization of urease enzyme, the stability and response time characteristics and the transducers used for biosensor development such as pH electrodes, ammonia gas sensing electrodes, ammonium ion-selective electrodes, optical, conductometric and amperometric transducers. Underlying the importance of this study is the fact that urea is toxic above certain concentrations and its continuous real time monitoring in clinical, environmental and food related environments is of utmost interest. The conventional analytical techniques used, although precise, are time consuming and mostly laboratory bound whereas biosensors have the advantages of ease of use, portability and the ability to furnish real time signals.     

基于纳米材料的化学与生物传感器研究进展

纳米材料由于其量子尺寸效应和表面效应,可以有效地提高化学或生物传感器的性能.同时,通过对纳米材料的进一步功能化设计与改造,可以研究开发超高灵敏度、超高选择性的新型传感器件.该文主要就金利通课题组近年来基于纳米材料修饰的化学与生物传感器方面的研究工作进行介绍并对该领域的发展作一展望.     

Acetylthiocholine/acetylcholine and thiocholine/choline electrochemical biosensors/sensors based on an organically modified sol–gel glass enzyme reactor and graphite paste electrode

Electrochemical sensors for acetylthiocholine and acetylcholine are described. The non-mediated electrochemistry of acetylthiocholine and thiocholine is studied on the surface of graphite paste electrode and results show that acetylthiocholine is directly oxidized/reduced at >0.32 V vs. Ag/AgCl in both acidic and basic medium. In basic medium, both cathodic and anodic peak currents are less as compared to that of the same amount in acidic medium, which shows that the kinetics of non-enzymatic hydrolysis of acetylcholine into electroactive thiocholine is faster in acidic medium and slower in basic medium. Thiocholine is directly oxidized/reduced at >0.35 V vs. Ag/AgCl with relatively larger anodic current compared to cathodic peak current similar to that of acetylcholine results recorded in acidic medium (pH 6.0). The electrochemical sensor/biosensors for acetylthiocholine/acetylcholine and thiocholine/choline are developed using two enzyme reactors: (1) acetylcholinesterase (AChE) encapsulated organically modified sol–gel glass, and (2) choline oxidase (ChO) immobilized within mediators (tetracyanoquinodimethane (TCNQ), tetrathiafulvalene (TTF), and dimethyl ferrocene (dmFc))-modified graphite paste electrodes. The AChE-immobilized into organically modified sol–gel glass behaves as the reactor for enzymatic hydrolysis of acetylthiocholine/acetylcholine into thiocholine/choline, whereas mediator- and ChO-modified paste electrodes are used for the detection of thiocholine/choline through mediated mechanism. The electrochemistry of AChE-generated thiocholine is studied at the mediator-modified electrodes in the presence and absence of ChO. It is observed that thiocholine undergoes both mediated and non-mediated oxidation in the absence of ChO as well as oxidation through enzyme-catalyzed mediated reactions. The results based on cyclic voltammetry on the oxidation of thiocholine at the surface of mediator-modified electrodes in the presence and absence of ChO are reported. In the presence of the ChO large anodic current is observed near the mediator's redox potentials as compared to the anodic current in the absence of enzyme, which shows mediated bioelectrochemistry of thiocholine. The typical response curves for the detection of thiocholine/choline using mediators and ChO-modified electrodes below 0.24 V vs. Ag/AgCl in 0.1 M Tris–HCl buffer pH 8.0 are reported. Comparative analytical performance on the mediated electrochemical responses of the biosensors is discussed.     

Fabrication of polypyrrole–glucose oxidase biosensor based on multilayered interdigitated ultramicroelectrode array with containing trenches

A miniature glucose biosensor has been developed based on electropolymerization of polypyrrole–glucose oxidase on a multilayered gold interdigitated ultramicroelectrode array with containing trenches. The basal band ultramicroelectrode with a functional width of 362 nm is fabricated using multilayered materials and conventional photolithographic techniques. The electrode surface is inside the containing trenches, the depth of which is larger than 1.5 μm. High quality electrodes with uniform geometries are characterized by microscopy and electrochemical techniques. The corrosion resistance is investigated on exposure to the normal saline, which indicates that the electrodes are adequate for acute experiments lasting a few hours. Fabricated by electropolymerization, the glucose oxidase/polypyrrole (GOx/PPy) biosensors can be used for detecting glucose concentration in the linear range of 0–10 mmol/L, with a sensitivity of 13.4 nA/(mmol L) and a correlation coefficient of 0.998, respectively.     

Preparation of Ag–Au nanoparticle and its application to glucose biosensor

In this paper, Ag–Au nanoparticles are produced in sodium-bis(2-ethylhexyl)-sulfosuccinate (AOT)–cyclohexane reverse micelle system. The properties of the obtained nanoparticles are characterized with transmission electron microscope (TEM) and UV–vis absorption spectrophotometer. Glucose biosensors have been formed with glucose oxidase (GOx) immobilized in Ag–Au sol. GOx are simply mixed with Ag–Au nanoparticles and crosslinked with a polyvinyl butyral (PVB) medium by glutaraldehyde. Then a platinum electrode is coated with the mixture. The effects of the various molar ratios of Ag–Au particles with respect to the current response and the stability of the GOx electrodes are studied. The experimental results indicate the current response of the enzyme electrode containing Ag–Au sol increase from 0.32 to 19 μA cm⁻² in the solution of 10 mM β-d-glucose. In our study, the stability of enzyme electrodes is also enhanced.     

Serum tumor marker detection on PEGylated lipid membrane using biosensor based on total internal reflection imaging ellipsometry

We describe highly sensitive, label-free, real time detection of the biomarker CA19-9 using microarray biosensors based on total internal reflection imaging ellipsometry (TIRIE), in which anti-CA19-9 is immobilized onto the PEGylated phospholipid membrane. Strong resistance against non-specific adsorption of PEGylated lipid membrane allows direct serum assay without the blocking agent. We find that PEG density has an influence on antibody assembly and only a proper amount of PEG is appropriate for antigen binding. Two different methods for antibody assembly are compared and finally protein A is preferred due to its higher protein binding efficiency. The estimated detection limit of CA19-9 is 18.2 U/ml, which is lower than the cut-off value for normal level (37 U/ml). Regression analysis between the results of microarray biosensor and electrochemiluminescence immunoassay (ECLIA) suggests a high correlation (R = 0.989). The capability for real-time monitoring of tumor marker with high sensitivity and selectivity in clinically relevant samples opens up substantial possibilities for early cancer diagnosis and treatment.     

A novel, electrically protein-manipulated microcantilever biosensor for enhancement of capture antibody immobilization

This study demonstrated a microcantilever biosensor for enhancement of capture antibody immobilization. The electrically protein-manipulated, microcantilever biosensor is featured with enhanced capture antibody immobilization, miniaturization, and high sensitivity. Thanks to the electric property of biological substances in a real environment, given charged proteins can be manipulated with attraction in solution under an electric field. It is evident that higher amount of capture antibody molecules immobilized onto sensing surfaces captures or detects specific molecules, indicating greater deflection and stresses as well. This however leads to significant cost in biosensors. With the merit of MEMS technique that allows highly fabrication-compatible integration into microcantilever biosensors, sparsely distributed antibody molecules in solution are attracted in focus onto a sensing solid surface under electric fields. As the sensing element of the gold-coated, V-shaped silicon nitride microcantilever also serves as an electrode, the electric fields are applied in a channel of flowing microfluidics by locally in-plane electrodes or by a top electrode arranged for three-dimensional fields. As expected, most charged proteins distributed in solution are effectively attracted onto the sensing area within the electric fields. This improves the efficiency of capture antibody immobilization and achieves an eight-fold reduction over the necessary amount of capture antibodies without applying electric fields. With such a successful manipulation of charged proteins, the novel microcantilever biosensor exhibits efficient use of capture antibodies in solution.