聚吡咯固定胆固醇氧化酶/普鲁士蓝安培传感器的研制

利用电聚合吡咯的方法将胆固醇氧化酶固定在普鲁士蓝 (PB)修饰玻碳电极表面 ,制成了一种新型胆固醇安培传感器。PB膜修饰电极催化过氧化氢电还原 ,于 0V(vs.Ag ACl)产生灵敏还原峰 ,利用安培法可对胆固醇进行间接测定。胆固醇的测定范围为 0～ 2× 10 - 4mol L ,检出限为 6× 10 - 7mol L ,灵敏度较当前胆固醇传感器有明显的提高。同时该传感器对胆固醇的测定避免了常规电化学传感器测定中样品所含大量的易氧化物质带来的干扰     

Prussian Blue Modified Amperometric Hg2+ Ion Biosensor Based on Glucose Oxidase Inhibition

In this research a Hg²⁺ ion biosensor was developed by combining Prussian blue (PB) with glucose oxidase (GOx) – an enzyme that can be inhibited by Hg²⁺ ions. An application of PB in the design of Hg²⁺ ion biosensor enabled detecting changes in hydrogen peroxide reduction current at low operational potential of 0.2 vs Ag|AgCl,KCl_sat. The described Hg²⁺ ion biosensor exhibited wide linear range from 27 μM to 247 μM of Hg²⁺ and higher maximal detectable concentration of Hg²⁺ than other GOx inhibition-based biosensors, making it convenient for the analysis of samples with high concentration of Hg²⁺ ions.     

A Cholesterol Biosensor Based on Entrapment of Cholesterol Oxidase in a Silicic Sol‐Gel Matrix at a Prussian Blue Modified Electrode

A cholesterol biosensors fabricated by immobilization of cholesterol oxidase (ChOx) in a layer of silicic sol‐gel matrix on the top of a Prussian Blue‐modified glassy carbon electrode was prepared. It is based on the detection of hydrogen peroxide produced by ChOx at ?0.05 V. The half‐lifetime of the biosensor is about 35 days. Cholesterol can be determined in the concentration range of 1×10^?6?8×10^?5 mol/L with a detection limit of 1.2×10^?7 mol/L. Normal interfering compounds, such as ascorbic acid and uric acid do not affect the determination. The high sensitivity and outstanding selectivity are attributed to the Prussian Blue film modified on the sensor.     

溶胶-凝胶法固定胆固醇氧化酶偶联普鲁士蓝化学修饰电极的研究

用溶胶-凝胶法将胆固醇氧化酶固定在普鲁士蓝修饰的玻碳电极表面,制成了一种新型胆固醇传感器,实现了低电位下对胆固醇的间接测定,胆固醇的测定范围伏安法为5×10^-7～8×10^-5mol/L,安培法为5×10^-6～5×10^-4mol/L.伏安法检出限为1.2×10^-7mol/L,是目前所见灵敏度最高的胆固醇传感器之一,该传感器对胆固醇的测定可避免常规电化学传感器测定中由于样品中大量存在的易氧化物质所带来的干扰,该传感器的寿命长,使用次数在300次以上.     

Nafion—四硫富瓦烯修饰蜡浸石墨电极的葡萄糖传感器

本文用四硫富瓦烯（ＴＴＦ）作为酶与电极之间的电子传递体，通过牛血清蛋白和戊二醛交联剂，把葡萄糖化氧化酶固定在Ｎａｆｉｏｎ－ＴＴＦ修饰石墨电极上，最后在电极修饰一层Ｎａｆｉｏｎ膜，制备成葡萄糖传感器。Ｎａｆｉｏｎ膜不仅能防止四硫富瓦燃流失，而且能氢抗坏血酸，尿酸等电活生物质阻挡在电极外，防止其干扰，同时具有防污性能。通过实验表明ＴＴＦ＾＋，ＴＴＴ＾２＾＋都能够氧化葡萄糖氧化酶中的辅酶（ＦＡＤＨ２）。     

Nafion－Ferrocene修饰的次黄嘌呤传感器

本文用Ｆｅｒｒｏｃｅｎｅ（ＦＣ）作为黄嘌呤氧化酶与电极之间的电子传递体，通过牛血清白蛋白和戊二醛交联剂，把黄嘌呤氧化酶固定在Ｎａｆｉｏｎ－Ｆｃ修饰电极表面，制备成次黄嘌呤传感器。该传感器的线性范围为５．０×１０－５—７．５×１０－４ｍｏｌ／Ｌ，响应时间小于７ｏｓ。     

普鲁士蓝修饰铂盘电极的胆固醇传感器的研制

在制备普鲁士蓝膜修饰铂盘电极的基础上 ,利用修饰电极对过氧化氢的电催化还原特性 ,制得了性能优良的胆固醇传感器。作者系统地考察了有关修饰膜制备和测试实验条件对传感器性能的影响 ,结果表明 :传感器的最佳工作电位是 0 .0 5V ,测试溶液的最适pH值为 7.0。在选定的工作条件下 ,传感器的灵敏度为 15 0nA mmol·L- 1 ,线性范围为 0 .2～ 2mmol/L ,响应时间为 1min ,寿命在 1个月以上。本方法制得的传感器能有效消除抗坏血酸、尿酸的干扰 ,有望用于血液中胆固醇的测定     

Amperometric Study of Au‐Colloid Function on Xanthine Biosensor Based on Xanthine Oxidase Immobilized in Polypyrrole Layer

Four kinds of xanthine oxidase (XOD) based amperometric biosensors were fabricated and their analytical performances were compared. Polypyrrole (PPY)/XOD biosensor was constructed by electrochemical oxidation of pyrrole in the solution containing xanthine oxidase and pyrrole in this paper. Colloidal Au was then immobilized on the biosensor. On the other hand, electron mediator, Prussian Blue (PB), was deposited on the electrode before the immobilization of PPY/XOD to enhance electron‐transfer rate and current response. The results showed that PPY/XOD, PPY/XOD/Au‐colloid, PB/PPY/XOD and PB/PPY/XOD/Au‐colloid biosensors exhibit good response to xanthine in 1×10^?6 M and 2×10^?5 M and Michaelis‐Menten constants (K_m) of these biosensors were 242.2, 113.4, 144.5, 43.2 μmol?L^?1, respectively. The dependence of current responses with applied voltages was discussed, and different mechanisms of these biosensors were discussed. It has been found that colloidal Au can enhance the current response at the same concentration of xanthine solution and decrease the energy‐barrier of electron‐transfer reaction on the electrode.     

Development An Amperometric Microbial-enzyme Hybrid Cholesterol Biosensor Based On Ionic Liquid MWCNT Carbon Paste Electrode

In this study we report the development of an amperometric cholesterol biosensor based on cholesterol oxidase from Pseudomonas sp. and catalase immobilized in carbon paste electrode (CPE) modified with multiwall carbon nanotubes (MWCNT) and ionic liquid (IL). The working electrode (CPE/MWCNT-IL/Microorganism (MO)-Catalase) was characterized by impedance spectroscopy and cyclic voltammetry at different stages of its construction. This proposed cholesterol biosensor performed linear relationship in the range of 5–600 μM with a low detection limit of 1.52 μM. The biosensor showed good sensitivity and high selectivity and it was successfully applied for the measurement of cholesterol levels in lyophilized serum samples.     

Preparation of Three‐Dimensional Ordered Macroporous Prussian Blue Film Electrode for Glucose Biosensor Application

Ordered 3D interconnected macroporous Prussian blue (PB) films were electrochemically fabricated by using colloidal crystals of polystyrene beads as sacrificial templates. The prepared PB film electrodes have excellent catalytic activity towards the reduction of hydrogen peroxide. The PB structure was further used as functional interface for fabricating an enzyme‐based glucose sensor by using surface modification technique based on the electrostatic interactions. The resulted sensor has higher functional density, and larger surface area. The interconnected macroporous structure allows enhanced mass transport. These characteristics of the sensor enable us to detect glucose with high sensitivity. Therefore, the present 3D ordered macroporous film sensor exhibits wide linear detection range towards glucose, acceptable reproducibility and operational and storage stability. The present approach is promising for the generation of high‐enzyme‐content thin films with tailored bioactivity.     

碳纳米管负载铂修饰电极结合溶胶-凝胶技术制备胆固醇传感器

制作了碳纳米管和碳纳米管负载铂镶嵌修饰的浸蜡石墨电极,实验发现纳米铂的引入使修饰电极对过氧化氢的还原有更好的电催化性能。用溶胶凝胶法将胆固醇氧化酶固定在碳纳米管负载铂修饰的浸蜡石墨电极表面,构建了一种新型的胆固醇生物传感器。实现了低电位下对胆固醇的间接测定。胆固醇浓度在4.0×10-6~1×10-4mol/L范围内与其峰电流的增量呈现良好的线性关系。检出限为1.4×10-6mol/L。该传感器的灵敏度高,选择性好,可以避免样品中大量易氧化物质的干扰,且寿命长,性能稳定。     

掺杂纳米普鲁士蓝溶胶-凝胶修饰葡萄糖生物传感器

采用溶胶-凝胶法制备了纳米普鲁士蓝微粒,将含纳米普鲁士蓝微粒的TiO2溶胶-凝胶固定在玻碳电极表面得到纳米普鲁士蓝修饰电极,该电极对H2O2产生灵敏的响应,线性范围为0．5～400μmoL／L,较常规普鲁士蓝修饰电极(线性范围为25～500μmol／L)灵敏。电极表面再用溶胶．凝胶法固定葡萄糖氧化酶后构建了葡萄糖生物传感器,响应范围0～20mmoL／L,葡萄糖氧化酶表观米氏常数为8．04mmoL／L。实验表明,该法适合于批量制作高灵敏和高重现性的生物传感器。     

基于立方体纳米氧化亚铜修饰的安培型葡萄糖生物传感器的制备及性能研究

将合成的立方体纳米氧化亚铜用于修饰玻碳电极,在其上固定葡萄糖氧化酶,构建了高灵敏的安培型葡萄糖生物传感器.采用X射线衍射(X RD)、扫描电镜(SEM)对合成的立方体纳米氧化亚铜及其修饰电极进行了表征.结果表明,合成的纳米氧化亚铜为均匀的立方体形状.采用循环伏安法(CV)、交流阻抗谱(EIS)、差分脉冲伏安法(DPV)及计时电流法(CA)考察了修饰电极的电化学行为.在含0.1 mmol/L葡萄糖的磷酸盐缓冲溶液(pH 7.4)中研究了立方体纳米氧化亚铜修饰电极的循环伏安(CV)响应,实验结果表明,此修饰电极对葡萄糖显示出良好的电催化性能.DPV响应电流与葡萄糖的浓度在5.0×10-6 ～4.0× 10-3mol/L范围内呈良好的线性关系,线性相关系数R2=0.9983,检出限为6.8×10-7 mol/L(S/N=3).CA实验结果表明,尿酸、抗坏血酸、D-果糖对传感器不产生干扰.本传感器具有较好的重现性和稳定性,可用于实际样品中葡萄糖的检测.     

An Electrochemical Biosensor with Cholesterol Oxidase/ Sol‐Gel Film on a Nanoplatinum/Carbon Nanotube Electrode

The carbon nanotubes decorated nanoplatinum (CNT‐Pt) were prepared using a chemical reduction method and a novel base electrode was constructed by intercalating CNT‐Pt on the surface of a waxed graphite electrode. The results showed that the nano‐particles of platinum at a waxed graphite electrode exhibits high catalytic activity for the reduction of hydrogen peroxide. The cholesterol oxidase (ChOx), chosen as a model enzyme, was immobilized with sol‐gel on the CNT‐Pt base electrode to construct a biosensor. The current response of the biosensor for cholesterol was very rapid (<20 s). The linear range for cholesterol measurement was 4.0×10^?6 mol/L ?1.0×10^?4 mol/L with a detection limit of 1.4×10^?6 mol/L. The experiments also showed that the ChOx/sol‐gel/CNT‐Pt biosensor was sensitive and stable in detecting cholesterol in serum samples.     

Amperometric cholesterol biosensor based on immobilized cholesterol esterase and cholesterol oxidase on conducting polypyrrole films

Fabrication of an amperometric cholesterol biosensor by co-immobilization of cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) onto conducting polypyrrole (PPY) films using electrochemical entrapment technique is described. Electrochemical polymerization was carried out using a two-electrode cell configuration at 0.8 V. Characterization of resulting amperometric biosensor for the estimation of cholesterol has been experimentally determined in terms of linear response range, optimum pH, applied potential, temperature, and shelf-life. These PPY/ChEt/ChOx electrodes can be used for cholesterol ester estimation from 1 to 8 mM and have shelf-life of about 4 weeks at 4 °C during which about 15 estimations of cholesterol ester could be made. The sensitivity of PPY/ChEt/ChOx electrode has been found to be 0.15 μA/mM and the apparent K_m value for this electrode is 9.8 mM. Conductivity of the polymer films found to be about 3×10⁻³ S/cm.     

A Highly Sensitive Amperometric Galactose Biosensor Based on Graphene-doped Sol-gel-derived Titania-Nafion Composite Films

A highly sensitive amperometric galactose biosensor was developed by encapsulating galactose oxidase within the graphene-doped sol-gel titania-Nafion composite film on platinized glassy carbon electrode. Due to the combined electrocatalytic activity of graphene and Pt NPs on the electrode towards hydrogen peroxide as well as the mesoporous nature of the titania-Nafion composite, the present galactose biosensor exhibited relatively fast response time under 2 s, high sensitivity of 40.6 mAM⁻¹cm⁻², and wide dynamic range over three orders of magnitude with a detection limit of 3.78×10⁻⁶ M (S/N=3). In addition, the biocompatible composite in the biosensor secures excellent long-term stability.     

Amperometric biosensors based on the immobilization of oxidases in a Prussian blue film by electrochemical codeposition

Prussian blue has been formed by cyclic voltammetry onto the basal pyrolytic graphite surface to prepare a chemically modified electrode which provides excellent electrocatalysis for both oxidation and reduction of hydrogen peroxide. It is found for the first time that glucose oxidase or -amino oxidase can be incorporated into a Prussian blue film during its electrochemical growth process. Two amperometric biosensors were fabricated by electrochemical codeposition, and the resulting sensors were protected by coverage with a thin film of Nafion. The influence of various experimental conditions was examined for optimum analytical performance. The glucose sensor responds rapidly to substrates with a detection limit of 2 × 10⁻⁶ M and a linear concentration range of 0.01–3 mM. There was no interference from 2 mM ascorbic acid or uric acid. Another ( -amino acid) sensor gave a detection limit of 3 × 10⁻⁵ M -alanine, injected with a linear concentration range of 7.0 × 10⁻⁵-1.4 × 10⁻² M. Glucose and -amino acid sensors remain relatively stable for 20 and 15 days, respectively. There is no obvious interference from anion electroactive species due to a low operating potential and excellent permselectivity of Nafion.     

Graphene/Poly(vinylferrocene) Composite Based Amperometric Biosensor for L‐lysine Determination

A novel and sensitive amperometric biosensor for L‐lysine determination based on a glassy carbon electrode (GCE) modified with graphene (GR) and redox polymer poly(vinylferrocene) (PVF) was constructed. L‐lysine‐α‐oxidase was immobilized onto the modified GCE by a glutaraldehyde/bovine serum albumin cross‐linking procedure. SEM, CV and EIS were used for the characterization of the surface morphology and stepwise fabrication processes of PVF/GR composite. Optimal composition of the biosensor and experimental conditions that affect the performance of the biosensor are discussed. The effect of buffer pH on biosensor response was studied in detail over a wide pH range. L‐lysine biosensor displayed a linear range of 9.9×10⁻⁷ ‐ 3.1×10⁻⁴ M with a low detection limit of 2.3×10⁻⁷ M and K_M ^app value of 0.4 mM. The L‐lysine biosensor was tested using pharmaceutical sample and cheese with satisfactory results.     

钴原卟啉附修饰玻碳电极为基底的胆固醇酶电极

本文利用钴原卟啉对H₂O₂氧化有很高催化活性的特点,以钴原卟啉修饰玻碳电极为基底,戊二醛交联法固定胆固醇氧化酶,以电聚合邻苯二胺膜抗干扰、抗毒化.得到了线性范围为0.1～2mmol/L,响应时间在30s以内,可连续使用150次的胆固醇酶电极.     

Chloroperoxidase Modified Electrode for Amperometric Determination of 2,4,6‐Trichlorophenol

A carbon paste‐poly(o‐phenylendiamine)‐modified electrode to be used as amperometric biosensor for 2,4,6‐trichlorophenol (TCP) is described. The enzyme chloroperoxidase (EC 1.11.1.10) from Caldariomyces fumago is immobilized through dispersion in a graphite paraffin oil carbon paste covered by an electrogenerated poly(o‐phenylendiamine) (PPD) layer. The main enzymatic dehalogenation product, 2,6‐dichloro‐1,4‐benzoquinone (DCQ) is characterized by liquid chromatography‐mass spectrometry and cyclic voltammetry. This product is electrochemically active and can be detected amperometrically at +150 mV vs. Ag|AgCl|KCl (3 M). The biosensor exhibits a response time of 4 min, a detection limit of 10^?7 M, and a dynamic linear range between 10^?7 and 10^?6 M. Selectivity as well as operating and storage stability were evaluated.