基于Nafion共固定Pt/PEDOT/MWCNTs复合材料和辣根过氧化物酶电化学H2O2生物传感器

以多壁碳纳米管(MWCNTs)为载体,采用改进的一步化学合成法制备了Pt/聚3,4-乙烯二氧噻吩(PEDOT)/MWCNTs复合材料,以Nafion共固定此复合材料和辣根过氧化物酶(HRP)从而研制出性能优良的生物传感器。利用扫描电子显微镜(SEM)、傅立叶变换红外(FTIR)光谱和紫外-可见(UV-Vis)吸收光谱对制得的复合材料进行表征,同时通过循环伏安法详细探讨了该传感器对H2O2的响应性能。结果表明,固定的HRP仍能维持其结构和生物活性,并进行有效和稳定的直接电子转移。该方法由于使用了载体MWCNTs及NaBH4的进一步还原过程,明显增强了传感器对H2O2的电催化活性。在优化条件下,该传感器对H2O2在0.008～1.8mmol/L浓度范围内成线性相关,检出限为0.4μmol/L,且具有良好的重现性、稳定性和选择性。     

基于SiO2纳米粒子固定辣根过氧化物酶的生物传感器

制备了尺寸均一的SiO2纳米粒子(60nm),并将其用于固定辣根过氧化物酶.以儿茶酚为电子媒介体制得的H2O2传感器的检测范围为1.7×10-7～1.9×10-5mol/L,检出限为8.3×10-8mol/L.达到95%稳态电流所用时间少于10s.该传感器的米氏常数为7.8μmol/L,表明所固定的酶具有较高的生物活性.     

磁性纳米粒子固定辣根过氧化物酶的生物传感器

利用FeSO4与FeCl3合成了磁性Fe3O4纳米粒子,并进一步利用3-氨丙基-3-乙氧基硅烷(APS)和戊二醛溶液将辣根过氧化物酶共价固定于该磁性纳米粒子表面,研究了该磁性颗粒的磁学性能,通过磁力将其修饰于固体石蜡碳糊电极表面制成了酶修饰电极。考察了该传感器对H2O2的电化学响应。该生物传感器可对H2O2进行测定,线性范围为1.2×10-7~8.3×10-5mol/L;检出限为4.5×10-8mol/L。利用磁性纳米粒子所制得的酶修饰电极具有催化性能高、稳定性好、造价低和修饰层易更新等优点,有望得到更多的实际应用。     

基于石墨烯-壳聚糖-辣根过氧化物酶的H2O2生物传感器的研制

制备了石墨烯-壳聚糖(GR-CS)纳米复合材料,并将之与辣根过氧化物酶(HRP)混合,构建了基于石墨烯-壳聚糖-辣根过氧化物酶的生物传感器(GR-CS-HRP/GC)。探针及循环伏安研究表明,该界面具有优异的电子传导能力、较大的比表面积和良好的生物相容性,对H2O2的还原显示出较好的电催化活性,在工作电位为-0.2 V,0.05 mol/L的磷酸盐缓冲盐溶液(PBS,pH 6.8)中,该酶传感器对过氧化氢响应灵敏度高,检测范围宽,测定H2O2的线性范围为5.0×10-7～2×10-3mol/L(相关系数为0.998)。检出限为2.0×10-7mol/L(S/N=3)。并且表现出良好的稳定性和高选择性。该电极用于实际样品中H2O2的测定,结果令人满意。     

碳纳米管/TiO2薄膜固定酶的生物传感器及电催化氧化H2O2的研究

采用酸性溶胶法在碳纳米管上负载纳米TiO2颗粒,并制备了CNT-TiO2薄膜固定辣根过氧化物酶的生物传感器。研究了该生物传感器在磷酸盐缓冲溶液中对H2O2的电催化氧化作用及实验条件的影响。结果表明该生物传感器对H2O2表现出良好的电催化性能,在最佳实验条件下,对H2O2检测的线性范围为:4.2×10-7mol/L~3.2×10-3mol/L。检出限为:7.22×10-8mol/L。     

壳聚糖/聚乙烯吡咯烷酮固定辣根过氧化物酶的过氧化氢生物传感器

用一种新型的壳聚糖(CS)/聚乙烯吡咯烷酮(PVP)复合膜在玻碳电极(GCE)上固定辣根过氧化物酶(HRP)。以乙二醛作交联剂,二茂铁(Fc)作媒介体,制备过氧化氢生物传感器。红外光谱表明:CS与PVP交联形成了一种新的高聚物,实验结果证明该聚合物适合辣根过氧化物酶的固定。该传感器对于H2O2的电流响应在5 s内即可达到最大,线性范围为6.0×10-6~1.7×10-4mol/L;检出限为2.5×10-6mol/L。该传感器的检测灵敏度为62.5μA/mmol/L。     

基于静电吸附多层膜固定酶的过氧化氢生物传感器的研究

以玻碳电极为基底,电聚合2,6-吡啶二甲酸(PDC),使形成一带负电的界面,再通过静电吸附自组装一层聚阳离子聚丙烯胺(PAH),用于静电吸附固定辣根过氧化物酶并以此方法固定多层酶膜制备过氧化氢传感器.探讨了工作电位、介体浓度、pH对电极响应的影响,考察了电极的重现性、干扰及使用寿命.该传感器在H₂O₂浓度4.6×10^-6～3.5×10^-3 mol/L范围内有线性响应, 检出限为2×10^-6 mol/L.电极在用于实际试样回收率的测定中,结果良好.     

基于辣根过氧化物酶/纳米金/L-半胱氨酸/聚邻氨基苯甲酸膜修饰的过氧化氢生物传感器

描述了测定过氧化氢的第三代电流型生物传感器。为了制备生物传感器，邻氨基苯甲酸（oABA）被电聚合到铂电极的表面形成具有抗干扰能力的静电排斥层。辣根过氧化物酶（HRP）通过纳米金（Nano-Au）的吸附固定到修饰了聚邻氨基苯甲酸及L-半胱氨酸的电极上。过氧化氢的测量是在相对于饱和甘汞电极的＋20 mV处进行的。修饰好的电极具有快速的响应，优秀的再现性和灵敏度，宽的线性范围和低的干扰水平等特点。我们研究了温度和pH对电极响应的影响及传感器的稳定性。在优化的条件下，传感器对过氧化氢的线性范围是2.99×10^-6到3.55×10^-3 mol/L，灵敏度和检测下限分别为0.0177 A•L^－1•mol^－1和4.3×10-7 mol/L（S/N＝3）。传感器不到10 s就可以达到响应的95％。     

三氧化二铝溶胶-凝胶固定过氧化氢生物传感器

三氧化二铝溶胶凝胶将辣根过氧化物酶和硫堇同时固定在玻碳电极上,紫外-可见光谱结果表明酶在固定过程中生物活性保持得较好.传感器在pH 7.0外加电压为-0.22 V条件下,对过氧化氢浓度为1.76×10-3～5.5×10-2 mol/L的范围内呈线性响应,检出限为1.1×10-4 mol/L.传感器的选择性和稳定性较好,使用3个星期后,仍能保持其初始活性的80%.     

辣根过氧化物酶生物传感器的制备及其应用于过氧化氢的测定

通过将碳纳米管及二氧化钛复合材料(CNT-TiO2)修饰于金电极表面,并借其对辣根过氧化物酶的静电吸附和对羧酸基的高反应特性,使辣根过氧化物酶(HRP)固定在CNT-TiO2表面,制成了辣根过氧化物酶生物传感器(HRP-CNT-TiO2)。对此修饰电极在磷酸盐缓冲介质(pH7.2)中的电催化性质及其电催化反应的最佳条件作了研究。试验结果表明,此电极对过氧化氢有很好的电催化特性,且发现当过氧化氢的浓度在4.2×10-7~3.2×10-4mol.L-1之间与ΔI之间呈线性关系,检出限(S/N=3)为7.2×10-8mol.L-1。为试验方法的精密度,对过氧化氢的浓度水平为5×10-5mol.L-1的条件下进行了8次测定,结果的RSD值为4.5%。     

Mediatorless Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Immobilized on 4‐Carboxyphenyl Film Electrografted on Gold Electrode

A novel method to fabricate a third‐generation hydrogen peroxide biosensor was reported. The electrode was first derivatized by electrochemical reduction of in situ generated 4‐carboxyphenyl diazonium salt (4‐CPDS) in acidic aqueous solution yielded stable 4‐carboxyphenyl (4‐CP) layer. The horseradish peroxidase (HRP) enzyme was then covalently immobilized by amidation between NH₂ terminus of enzyme and COOH terminus of 4‐CP film making use of the carbodiimide chemistry. Electrodeposition conditions used to control electrode functionalization density and film electron transfer kinetics were assessed by chronoamperometry and electrochemical impedance spectroscopy. The immobilized HRP displayed excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H₂O₂) without any mediators. The effect of various operational parameters was explored for optimum analytical performance. The reported biosensor exhibited fast amperometric response (within 5 s) to H₂O₂. The detection limit of the biosensor was 5 μM, and linear range was from 20 μM to 20 mM. Furthermore, the biosensor exhibited high sensitivity, good reproducibility, and long‐term stability.     

A Third‐Generation Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Immobilized in Carbon Nanotubes/ SBA‐15 Film

A new third‐generation biosensor for H₂O₂ assay was developed on the basis of the immobilization of horseradish peroxidase (HRP) in a nanocomposite film of carbon nanotubes (CNTs)‐SBA‐15 modified gold electrode. The biological activity of HRP immobilizing in the composite film was characterized by UV‐vis spectra. The HRP immobilized in the nanocomposite matrix displayed excellent electrocatalytic activity to the reduction of H₂O₂. The effects of the experimental variables such as solution pH and working potential were investigated using steady‐state amperometry. Under the optimal conditions, the resulting biosensor showed a linear range from 1 µM to 7 mM and a detection limit of 0.5 µM (S/N=3). Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.     

Amperometric Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Immobilized on Fe3O4/Chitosan Modified Glassy Carbon Electrode

A new type of amperometric hydrogen peroxide biosensor was constructed based on horseradish peroxidase (HRP) immobilized on Fe₃O₄/chitosan modified glassy carbon electrode. The effects of some experimental variables such as the concentration of supporting electrolyte, pH, enzyme loading, the concentration of the mediator of methylene blue (MB) and the applied potential were investigated. The linear range of the calibration curve for H₂O₂ was 2.0×10^?4–1.2×10^?2 M with a detection limit of 1.0×10^?4 M (S/N=3). The response time was less than 12 s. The apparent Michaelis‐Menten constant K_m was 21.4 mM and it illustrated the excellent biological activity of the fixed enzyme. In addition, the biosensor had long‐time stability and good reproducibility. And this method has been used to determine H₂O₂ concentration in the real sample.     

辣根过氧化物酶/多壁碳纳米管修饰铂电极生物传感器用于过氧化氢的循环伏安测定

将1mg多壁碳纳米管(MWCNT's)分散在5mL的0.5g·L~(-1)壳聚糖溶液中后,滴涂在铂电极表面,制得多壁碳纳米管修饰电极。将上述修饰电极在辣根过氧化物酶(HRP)溶液中浸泡8h,在MWCNT's修饰电极表面静电吸附辣根过氧化物酶,制成过氧化氢生物传感器,用于过氧化氢的测定。试验结果表明:在pH 6.0的磷酸盐缓冲溶液中,HRP/MWCNT's修饰电极对过氧化氢具有明显的电催化还原作用,过氧化氢的浓度在3.5×10~(-5)～9.0×10~(-3)mol·L~(-1)范围内与其还原峰电流呈线性关系,检出限(3S/N)为2.4×10~(-5)mol·L~(-1)。用标准加入法作回收试验,回收率在96.0%～101.8%之间。     

A Third‐Generation Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Covalently Immobilized on Electrografted Organic Film on Screen‐Printed Carbon Electrode

A new convenient strategy to fabricate a third‐generation hydrogen peroxide biosensor was described. The screen‐printed carbon electrode (SPCE) was first modified with a layer of 4‐nitrophenyl assembled from the 4‐nitroaniline diazonium salt synthesized in situ in acidic aqueous solution. Next, the nitro groups were converted to amines followed by crosslinking to the horseradish peroxidase (HRP) by glutaraldehyde. The redox chemistry of the active center of the HRP was observed and the HRP‐modified electrode displayed electrocatalytic activity towards the reduction of hydrogen peroxide (H₂O₂) without any mediators. H₂O₂ was determined in a linear range from 5.0 μM to 50.0 μM, with a detection limit of 1.0 μM. Furthermore, the biosensor exhibited fast amperometric response, good reproducibility and long‐term stability.     

A Novel Amperometric Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Incorporated in Organically Modified Sol-Gel Glass Matrix/Graphite Paste with Multiwalled Carbon Nanotubes

We herein report an electrochemical hydrogen peroxide sensor based on horseradish peroxidase immobilized in organically modified sol-gel glass (ormosil) with mediator ferricyanide along with multiwalled carbon nanotubes (mwcnts). The ormosil material is converted to fine powder followed by incorporation within graphite paste electrode. The electrochemistry of redox materials encapsulated within ormosil has been studied. The requirement of mwcnts is examined. The ormosil prepared with optimum concentration of mwcnts shows better redox electrochemistry as compared to that made without mwcnts. The biosensor has been characterized by cyclic voltammetry and chroanoamperometry. The performance, stability, and reproducibility of a new peroxide biosensor are reported.     

基于纳米金自组装膜固定辣根过氧化物酶的生物传感研究

将辣根过氧化物酶(HRP)通过纳米技术和自组装技术固定于电极表面,制得了酶修饰电极.纳米金与HRP形成了静电复合物并高效地保持了HRP的生物活性,以对苯二酚作为电子媒介体,差示脉冲伏安法(DPV)研究生物酶电极测定H2O2的线性范围为5.0×10-6～1.0×10-3 mol/L,检测限为2.5×10-6 mol/L,线性方程为△I=0.34765+4.05553CH2O2(mM).酶电极的表观米氏常数(K(app))为0.0675 mmol/L.实验同时证明该生物酶电极具有良好的稳定性和使用寿命.     

A Novel Hydrogen Peroxide Biosensor Based on Adsorption of Horseradish Peroxidase onto a Nanobiomaterial Composite Modified Glassy Carbon Electrode

In this work, a novel hydrogen peroxide biosensor derived from maize tassel (MT) and multiwalled carbon nanotube (MWCNT) composite was used to adsorb horseradish peroxidase (HRP) onto the surface of a glassy carbon electrode through electrostatic interactions. The morphology and structure of the products were characterized by SEM, FTIR and UV‐visible spectroscopy. The electrochemical and electrocatalytic performance of the HRP/MT‐MWCNT/GCE was studied using voltammetric and amperometric methods. The amperometric response of the biosensor varied linearly with concentration of H₂O₂ from 9 µM to 1 mM with detection limit of 4.0 µM (S/N=3). Furthermore, the biosensor exhibited good reproducibility and stability.     

A MgO Nanoparticles Composite Matrix‐Based Electrochemical Biosensor for Hydrogen Peroxide with High Sensitivity

A novel horseradish peroxidase (HRP) electrochemical biosensor based on a MgO nanoparticles (nano‐MgO)‐chitosan (chit) composite matrix was developed. The morphology of nano‐MgO‐chit nanocomposite was examined by scanning electron microscopy (SEM). The interaction between nano‐MgO‐chit nanocomposite matrix and enzyme was characterized with UV‐vis spectra. This proposed composite material combined the advantages of inorganic nanoparticles and organic polymer chit. The HRP immobilized in the nanocomposite matrix displayed excellent electrocatalytic activity to the reduction of H₂O₂ in the presence of hydroquinone as a mediator. The effects of the experimental variables such as solution pH and the working potential were investigated using steady‐state amperometry. The present biosensor (HRP‐modified electrode) had a fast response towards H₂O₂ (less than 10 s), and excellent linear relationships were obtained in the concentration range of 0.1–1300 μM, with a detection limit of 0.05 μM (S/N=3). Moreover, the stability and reproducibility of this biosensor were evaluated with satisfactory results.