多孔硅-酶复合电极对葡萄糖溶液的电化学检测

多孔硅（PS）具有纳米级尺寸,高的表面积比和生物兼容性为固定生物分子提供了有利的条件。文章采用光电化学腐蚀的方法制备出多孔硅,并将3-氨基丙基三乙氧基硅烷（APTS）共价结合到多孔硅表面实现其生物功能化。通过戊二醛（Gluta）交联的方式将葡萄糖氧化酶（GOD）固定到生物功能化多孔硅上,形成GOD-Gluta-APTS-PS复合结构并用作电化学测量的工作电极。铂金和饱和甘汞电极分别作辅助电极和参比电极。通过测量还原电流对数与电极电势的关系以及计时电流曲线,对10×10^-6-55×10^-6mol dm^-3浓度范围的葡萄糖水溶液进行测量分析,发现还原电流与葡萄糖溶液在一定范围内有线性响应关系。制成的多孔硅酶复合电极间隔5天重复使用1次,20天内性能能保持基本不变。     

金属与非金属纳米颗粒增强葡萄糖生物传感器

为了提高葡萄糖传感器的灵敏度和抗干扰性,利用纳米增强效应,以Au、Ag、Pt、SiO2纳米颗粒及金属-无机复合纳米颗粒与聚乙烯醇缩丁醛(PVB)构成复合固定酶膜基质,采用溶胶-凝胶法固定葡萄糖氧化酶(GOD),组成葡萄糖生物传感器.研究表明,纳米颗粒可以大幅度地提高固定化酶的催化活性,增加电极的电流响应灵敏度,改进生物传感器的抗干扰性能,使信噪比提高了32倍.     

基于离子液体功能化石墨烯/碳纳米管的葡萄糖传感器的研究(英文)

将离子液体功能化的石墨烯/碳纳米管(G-IL/CNTs)修饰到玻碳电极上,再固载上葡萄糖氧化酶(GOD)和辣根过氧化物酶(HRP),构筑了新型的(G-IL/CNTs)/(GOD+HRP)/GC双酶葡萄糖传感器。用SEM观察电极形貌,发现碳纳米管类似于导线穿插在石墨烯片层中,连接了各石墨烯片层,两者结合形成了三维立体结构,明显提高了石墨烯的分散性,同时由于功能化后的石墨烯与碳纳米管的协同作用,该传感器在葡萄糖的检测上表现了良好的分析性能,传感器的线性范围为0. 004～5 mmol/L,灵敏度为53. 89μA mmol/L~(-1)cm~(-2),检出限为3. 99×10~(-7)mol/L(S/N=3)。     

新型CMCS/WMCNTs修饰电极对槲皮素的电化学检测及应用

研究了一种黄酮类物质槲皮素在新颖的多壁碳纳米管(WMCNTs)/羧甲基壳聚糖(CMCS)复合物修饰电极上的循环伏安行为。实验采用直接滴涂方法制备CMCS/WMCNTs修饰电极,在不同的pH、扫描速度、底液浓度、修饰材料等条件下通过循环伏安法来研究槲皮素在修饰电极上电化学行为。修饰电极与裸电极相比,峰电流有明显提升,表明修饰材料对槲皮素的电化学氧化还原行为有一定的催化增敏作用。槲皮素在pH=5.0的醋酸-醋酸钠(NaAc-HAc)缓冲溶液中有一对明显的氧化还原峰,电极过程为等量质子和电子参与的吸附控制过程,且还原峰电流与槲皮素浓度在(1.0×10~(-4)~1.0×10~(-3))mol/L范围内呈良好的线性关系。     

辣根过氧化物酶在多壁碳纳米管——壳聚糖膜中的电化学和生物传感性质

采用壳聚糖包裹的多壁碳纳米管膜固定辣根过氧化物酶(HaP)于玻碳电极表面,实现了HRP的直接电化学并以此酶膜制备了NO生物传感器.在磷酸缓冲溶液中固定在电极表面的HRP氧化还原式电位为-0.354 V(us.SCE),直接电子转移速率常数为4.24±1.02 s-1.研究结果表明,固定在电极表面的HRP能保持其对一氧化氮还原的生物电催化活性,该传感器在NO浓度为1.0×10-4~1.4×10-3 mol L-1范围内存在线性响应,响应时间小于11 s,NO的检出限为7×10-4 mol L-1.多壁碳纳米管特殊的电学性质和壳聚糖良好的生物相容性性使得构筑的HRP生物传感器呈现了良好的应用前景,尤其适用于痕量NO的检测.     

前列腺特异性抗体电化学免疫传感器的研制

利用自组装的方法在金电极上制得巯基丁二胺铜(Ⅱ)/纳米金胶/前列腺特异性抗体(抗PSA)免疫修饰电极。用该修饰电极对PSA进行检测,发现其循环伏安图的氧化还原峰电流都随PSA浓度的增高而降低,峰电位没有变化。其最佳实验条件包括:pH5.2的0.1mol/L磷酸盐缓冲液作为底液,以及用示差脉冲方式进行定量测定。结果显示:该传感器的氧化峰电流减少值与PSA浓度在0.005-0.48μg/mL范围内成线性关系,检测下限为2ng/mL.在40 ng/mLPSA浓度下八次测量相对标准偏差为2.9%,该免疫传感器的稳定性和抗干扰性都较好。对血清中的PSA进行检测,获得满意的结果。     

氢氧化氧化钴和铜修饰的ITO双电极上丙酮酸的电化学检测

采用电沉积技术在ITO导电基底上制备了氢氧化氧化钴(CoOx(OH)y/ITO)和铜(Cu/ITO)双电极,同时采用循环伏安技术研究了丙酮酸在该双电极上的电化学氧化还原。结果表明:丙酮酸在CoOx(OH)y/ITO上有氧化电流响应,在Cu/ITO上有还原电流响应。在此基础上,利用双电流通道计时电流法,分别在CoOx(OH)y/ITO和Cu/ITO电极上施加0.45V和-1.4V的电位。结果表明:丙酮酸响应的线性范围在CoOx(OH)y/ITO上为低浓度,Cu/ITO上为高浓度,从而利用该双电极在较宽浓度范围内(1.67μmol.L-1～6.01mmol.L-1),实现了丙酮酸的定量检测。     

基于石墨烯/金纳米棒的甲硝唑电化学行为及其检测

碱性条件下制备水中分散性良好的石墨烯,并通过一步还原法得到石墨烯/AuNRs复合材料。利用滴涂法制备石墨烯/AuNRs修饰电极,并研究了甲硝唑在该修饰电极上的电化学行为。结果表明,在pH=7.4时,甲硝唑在修饰电极上出现明显的氧化还原峰。甲硝唑在该修饰电极的还原峰峰电流与浓度在3.0×10-7～5.0×10-5 mol/L(S/N=3)范围内呈良好的线性关系,检出限为9.2×10-8 mol/L。该检测方法具有良好的灵敏度、选择性和稳定性,可用于甲硝唑药物的分析。同时也展现了这种新型的复合纳米材料在药物的检测中的应用潜力。     

叶酸在聚苯胺修饰铂电极上的电催化氧化行为

采用电化学聚合法制备了聚苯胺修饰的铂电极(PAN/Pt),并用循环伏安法(CV)研究了该电极对叶酸(FA)的电催化氧化性能。结果显示:FA在裸铂电极上的直接电化学氧化十分迟缓,无氧化峰出现,而在PAN/Pt修饰电极上0.561V处出现氧化峰,表明此电极对FA有很良好的电催化作用。另外,氧化峰电流与叶酸浓度在1×10-12 mol/L~1×10-6 mol/L范围内呈线性关系,检测限为1×10-11 mol/L。利用该电极测定市售叶酸片中的叶酸,获得令人满意的结果。     

基于花状MoS2微米材料的葡萄糖生物传感器的制备及其性能研究

本研究采用水热法制备了花状MoS₂微米材料, 将其作为电极构建葡萄糖生物传感器, 并研究了相关性能。结果表明: 水热法制备的MoS₂呈花状, 具有较好的结晶质量, 尺寸约为3.6 μm, 比表面积约为9.646 m²/g; MoS₂电极具有优良的电催化活性, 且电阻抗较小, 使得传感器对葡萄糖具有较好的响应。葡萄糖检测结果表明, 该传感器在0~20 mmol/L范围内, 氧化峰电流与葡萄糖浓度呈良好的线性关系, 相关系数(R)为0.9653, 灵敏度为262 μA•L/mmol。     

ZnS nanoparticles electrodeposited onto ITO electrode as a platform for fabrication of enzyme-based biosensors of glucose

The electrochemical and photoelectrochemical biosensors based on glucose oxidase (GOD) and ZnS nanoparticles modified indium tin oxide (ITO) electrode were investigated. The ZnS nanoparticles were electrodeposited directly on the surface of ITO electrode. The enzyme was immobilized on ZnS/ITO electrode surface by sol–gel method to fabricate glucose biosensor. GOD could electrocatalyze the reduction of dissolved oxygen, which resulted in a great increase of the reduction peak current. The reduction peak current decreased linearly with the addition of glucose, which could be used for glucose detection. Moreover, ZnS nanoparticles deposited on ITO electrode surface showed good photocurrent response under illumination. A photoelectrochemical biosensor for the detection of glucose was also developed by monitoring the decreases in the cathodic peak photocurrent. The results indicated that ZnS nanoparticles deposited on ITO substrate were a good candidate material for the immobilization of enzyme in glucose biosensor construction.     

基于二氧化硅球腔阵列的葡萄糖传感器研究

在二氧化硅球腔阵列电极上,通过电沉积普鲁士蓝和直接吸附葡萄糖氧化酶,制备了一种新型葡萄糖生物传感器。该传感器对酶催化反应产物过氧化氢的选择性催化还原特性可实现对葡萄糖的检测,实验结果表明,传感器的最佳工作电位是－0．3V,测试溶液的最佳pH值为6．0。在选定的工作条件下,传感器的线性范围为2．49×10-5－2．42×10-3mol／L,检测极限值为7．2×10-6mol／L（S／N=3）,米氏常数为1．136mmol／L。该方法制备的生物传感器能有效降低干扰,具有潜在的应用价值。     

Enzyme electrodes with conductive polymer membranes and Langmuir-Blodgett films

A glucose sensor consisting of a conductive polypyrrole membrane and a lipid Langmuir-Blodgett (LB) film has been investigated. Different arrangements of the biosensor on the electrodes examined were (1) electrode with glucose oxidase (GOD)-immobilized lipid LB films; (2) GOD-immobilized LB film coated on polypyrrole-modified electrode; (3) electrode with a GOD-immobilized polypyrrole membrane; (4) GOD-immobilized LB film coated on a GOD-polypyrrole-modified electrode. It was shown that the quality of the biosensor was apparently improved in case (4) with respect to both the detectable concentration range of glucose and the lifetime over which it could be used. The number of layers of the LB film has a marked influence on the sensitivity of the biosensor, an optimum number of layers existing for the best response. The mechanism of such an improvement is discussed.     

壳聚糖凝胶材料固定葡萄糖氧化酶制电极的研究

以壳聚糖为载体研究凝胶法固定葡萄糖氧化酶制电极。试验研究了载体壳聚糖的降解性；交联剂戊二醛的浓度、用量；电极的载酶量等固定化条件对所组建的传感器性能的影响。通过影响规律的分析、优化固定化条件的研究，找出了根据壳聚糖溶液粘度适当调整交联剂成二醛的用量和铂丝在酶膜母液中浸涂时间，克服壳聚糖的降解性对酶电极性能的影响，建立了制备性能相近的GOD传感器的方法。     

Electrochemical biosensor based on multi-walled carbon nanotubes and Au nanoparticles synthesized in chitosan

A new biosensor is prepared by cross-linking glucose oxidase (GOD) with glutaradehyde at the electrode combining Au nanoparticles (AuNP) with multi-walled carbon nanotubes (MWCNTs). Au nanoparticles-doped chitosan (CS) solution (AuNP-CS) is prepared by treating the CS solution followed by chemical reduction of Au (III) with NaBH4. MWCNTs are then dispersed in AuNP-CS solution. TEM, FT-IR, and UV-Vis show that the AuNP-CS solution is highly dispersed and stable. The synergistic effect between AuNP and CNTs of the AuNP-CNTs-CS material has been investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric methods. The modified glassy carbon electrode (GCE) allows low-potential detection of H2O2 with high sensitivity and fast response time. With the immobilization of GOD, a biosensor has been constructed. In phosphate buffer solutions (PBS, pH 7.0), nearly free interference determination of glucose has been realized at 0.4 V(vs. Ag/AgCl/3.0 M KCI) with a wide linear range from 2.0 x 10(-5) to 1.5 x 10(-2) M and a fast response time within 5s. The biosensor has been used to determine glucose in human serum samples and the results are satisfactory.     

Glucose biosensor from covalent immobilization of chitosan-coupled carbon nanotubes on polyaniline-modified gold electrode

An amperometric glucose biosensor was prepared using polyaniline (PANI) and chitosan-coupled carbon nanotubes (CS-CNTs) as the signal amplifiers and glucose oxidase (GOD) as the glucose detector on a gold electrode (the Au-g-PANI-c-(CS-CNTs)-GOD biosensor). The PANI layer was prepared via oxidative graft polymerization of aniline from the gold electrode surface premodified by self-assembled monolayer of 4-aminothiophenol. CS-CNTs were covalently coupled to the PANI-modified gold substrate using glutaradehyde as a bifunctional linker. GOD was then covalently bonded to the pendant hydroxyl groups of chitosan using 1,4-carbonyldiimidazole as the bifunctional linker. The surface functionalization processes were ascertained by X-ray photoelectron spectroscopy (XPS) analyses. The field emission scanning electron microscopy (FESEM) images of the Au-g-PANI-c-(CS-CNTs) electrode revealed the formation of a three-dimensional surface network structure. The electrode could thus provide a more spatially biocompatible microenvironment to enhance the amount and biocatalytic activity of the immobilized enzyme and to better mediate the electron transfer. The resulting Au-g-PANI-c-(CS-CNTs)-GOD biosensor exhibited a linear response to glucose in the concentration range of 1-20 mM, good sensitivity (21 μA/(mM·cm(2))), good reproducibility, and retention of >80% of the initial response current after 2 months of storage.     

Electrodeposition of chitosan-glucose oxidase biocomposite onto Pt-Pb nanoparticles modified stainless steel needle electrode for amperometric glucose biosensor

A glucose biosensor was fabricated by electrodepositing chitosan (CS)-glucose oxidase(GOD) biocomposite onto the stainless steel needle electrode (SSN electrode) modified by Pt–Pb nanoparticles (Pt–Pb/SSN electrode). Firstly, Pt–Pb nanoparticles were deposited onto the SSN electrode and then CS-GOD biocomposite was co-electrodeposited onto the Pt–Pb/SSN electrode in a mixed solution containing p-benzoquinone (p-BQ), CS and GOD. The electrochemical results showed that the Pt–Pb nanoparticles can accelerate the electron transfer and improve the effective surface area of the SSN electrode. As a result, the detection range of the proposed biosensor was from 0.03 to 9 mM with a current sensitivity of 0.4485 μA/mM and a response time of 15 s. The Michaelis constant value was calculated to be 4.9837 mM. The cell test results indicated that the electrodes have a low cytotoxicity. This work provided a suitable technology for the fabrication of the needle-type glucose biosensor.     

GOD/PPy/GC电极的电化学性能研究

采用电沉积法在玻碳(GC)电极表面合成纳米级聚吡咯(PPy),通过扫描电镜得到PPy的形貌。以PPy为载体,通过吸附法固定葡萄糖氧化酶(GOD),得到GOD/PPy/GC电极。利用循环伏安法对GOD/PPy/GC电极的电化学行为进行分析,结果表明,以PPy为载体可以很好地固定GOD并保持其生物活性。在0.1mol/L磷酸盐缓冲溶液中,无任何电子媒介体存在时,GOD/PPy/GC电极显示了很好的电催化性能。     

DNA as a support for glucose oxidase immobilization at Prussian blue-modified glassy carbon electrode in biosensor preparation

An amperometric glucose biosensor has been developed using DNA as a matrix of Glucose oxidase (GOx) at Prussian-blue (PB)-modified glassy carbon (GC) electrode. GC electrode was chemically modified by the PB. GOx was immobilized together with DNA at the working area of the PB-modified electrode by placing a drop of the mixture of DNA and GOx. The response of the biosensor for glucose was evaluated amperometrically. Upon immobilization of glucose oxidase with DNA, the biosensor showed rapid response toward the glucose. On the other hand, no significant response was obtained in the absence of DNA. Experimental conditions influencing the biosensor performance were optimized and assessed. This biosensor offered an excellent electrochemical response for glucose concentration in micro mol level with high sensitivity and selectivity and short response time. The levels of the relative standard deviation (RSDs), (<4%) for the entire analyses reflected a highly reproducible sensor performance. Through the use of optimized conditions, a linear relationship between current and glucose concentration was obtained up to 4 x 10(-4) M. In addition, this biosensor showed high reproducibility and stability.