金纳米颗粒增强一次性使用葡萄糖传感器的响应性能

为了提高一次性使用葡萄糖传感器响应灵敏度,降低工作电压,研究了加入金纳米颗粒的一次性使用电化学葡萄糖传感器的响应性能。采用水溶性高分子材料聚丙烯酰胺包埋葡萄糖氧化酶(GOD)制备酶电极,研究了聚丙烯酰胺溶液浓度、纳米颗粒加入以及加入量等对电极响应的影响。结果表明引入纳米粒子可显著增强葡萄糖传感器的响应灵敏度,明显缩短传感器的响应时间(<20s),降低传感器的工作电压(<0.4V)。     

光照纳米银颗粒对葡萄糖生物传感器响应电流的抑制

采用纳米银-壳聚糖复合膜固定葡萄糖氧化酶,构建葡萄糖生物传感器.利用计时电流法对不同光照时间纳米银颗粒组装的酶电极响应电流进行了表征.实验结果表明,光照纳米银颗粒可以抑制葡萄糖生物传感器的响应电流;随着光照时间的延长,纳米银颗粒的抑制作用逐渐增强,当光照时间达到120min时,葡萄糖生物传感器的响应电流最小(-3.953μA/cm2).葡萄糖生物传感器响应电流的抑制可能是由纳米银颗粒表面的Ag+离子浓度及表面性能的变化引起的.     

反胶束法制备纳米氧化锌及其在葡萄糖生物传感器中的应用

采用琥珀酸-2-乙基己基磺酸钠/环己烷反胶束体系制备纳米ZnO,并以此ZnO为载体固定葡萄糖氧化酶,用戊二醛交联制作成葡萄糖氧化酶电极. 实验结果表明,此酶电极表现出对葡萄糖溶液浓度的优良响应,线性范围在1′10-5~3′10-3 mol/L,响应灵敏度约为6 mA/(cm2×mmol/L),表观米氏常数为2.57 mmol/L. 还研究了温度和溶液pH值对电极电流响应的影响.     

基于纳米材料和对乙酰氨基酚的葡萄糖生物传感器的研究

将碳纳米管用Nafion膜分散后固定在玻碳电极表层,再用电化学方法将金纳米粒子沉积在碳纳米管修饰电极上,制备修饰电极。并以对乙酰氨基酚为电子媒介体,共同构建新型的葡萄糖酶生物传感器。实验结果表明:对乙酰氨基酚起到了很好的电子传递媒介体作用,传感器抗干扰能力增强,而且碳纳米管和金纳米粒子修饰电极能保持葡萄糖氧化酶的生物活性,电催化活性高,对葡萄糖的响应有明显的增敏效应。     

纳米金修饰电极对对苯二酚的电催化性能研究

本文使用纳米金制备出三种纳米金修饰电极。考察了不同电极对对苯二酚响应特性及响应线性范围。实验结果表明:在pH值=6.0的磷酸盐缓冲溶液中,使用滴涂法制备的纳米金/壳聚糖复合膜修饰电极对对苯二酚的催化响应更为显著,在0.2×10-4~1.6×10~(-4)mol/L浓度范围内,其氧化峰电流与对苯二酚浓度呈良好的线性关系,具有制备对苯二酚传感器的前景。     

纳米金修饰电极的制备及其性能研究

本文采用恒电流电沉积的方法,得到了纳米金修饰电极。通过扫描电子显微镜和电化学表征技术,考察了不同沉积电流对电沉积金的形貌和性能的影响。采用循环伏安法研究了最佳电沉积密度下修饰电极对葡萄糖的响应,表明此修饰电极有望应用于葡萄糖的检测。     

纳米金修饰电极的电化学研究

将由柠檬酸三钠与氯金酸制备的纳米金颗粒利用自组装方法修饰于金电极表面形成纳米金修饰电极,运用N5粒度测定仪、透射电子显微镜（TEM）和原子力显微镜（AFM）对纳米颗粒及其修饰电极进行了表征。利用循环伏安法（CV）与交流阻抗法（EIS）研究了纳米金修饰电极的电化学性质。     

电化学分析方法用于面膜中氯霉素现场快速检测

开发一种基于金纳米颗粒的便携式电化学传感器用于面膜中氯霉素现场快速分析。以电沉积的方式，采用沉积电位-0.6 V、沉积时间20 s，在便携式、可抛弃的丝网印刷电极表面沉积金纳米颗粒。结果显示，构建的负载金纳米颗粒的电化学传感器对氯霉素的电催化性能明显高于裸电极。实验考察了电解质溶液的pH，在较优条件下对不同浓度的氯霉素进行测定。结果显示，氯霉素浓度在0.02～0.5 mmol/L范围时，峰电流响应与氯霉素的浓度呈线性关系，方法的检出限为0.005 mmol/L。为了进一步评价方法的可行性，以市售面膜为实际样品进行添加回收实验。结果显示，三个添加水平下，氯霉素的添加回收率为106.01%～110.59%，相对标准偏差不大于3.66%(n=3)。结合手持式电化学工作站的无线蓝牙数据传输功能，可将现场检测结果实时传输至用户手机客户端，为面膜中氯霉素的现场快速筛查提供新的研究思路。     

一种基于多层金纳米颗粒的铵离子电化学传感器的研究

研究了使用通过硫醇化学连接在金电极表面上的金纳米颗粒(AuNP)的多层以制备基于丙氨酸脱氢酶(AlaDH)的铵(NH_4~+)离子生物传感器。在没有AuNP的情况下,尽管观察到电流响应较高,NH_4~+离子生物传感器没有表现出任何良好的线性响应范围。这项工作表明,加入AuNPs可以导致更高的NH_4~+离子浓度的检测,而不需要稀释高NH_4~+离子浓度样品,反应速度快。     

基于雪花形状的金纳米结构的抗坏血酸传感器的研究

本文利用一步合成装技术在碳纸表面合成雪花片形状的金(Au)纳米结构通过控制聚乙烯亚胺和Au纳米颗粒的浓度和反应时间。利用聚乙烯亚胺上的N与Au形成N-Au纳米颗粒组装成雪花形状Au纳米结构。用扫描电镜来表征雪花形状Au纳米结构的形貌,Au纳米结构很均匀的分散在碳纸表面,并不存在大的团聚。电化学技术(循环伏安法和计时电流分析法)检测雪花形状Au纳米结构对抗坏血酸的响应情况,显示修饰电极对抗坏血酸有很好的响应,在抗坏血酸浓度1×10~(-6)~1.15×10~(-4) mol/L的范围内,氧化电流与其浓度存在线性关系(R=0.998),检测限为6×10~(-7) mol/L;另外传感器具有很好的稳定性和选择性,为小分子污染物的检测提供新方法。     

Gold nanoparticles/single-stranded DNA-reduced graphene oxide nanocomposites based electrochemical biosensor for highly sensitive detection of cholesterol

High density and uniform distribution of the gold nanoparticles functionalized single-stranded DNA modified reduced graphene oxide nanocomposites were obtained by non-covalent interaction. The positive gold nanoparticles prepared by phase inversion method exhibited good dimensional homogeneity and dispersibility, which could readily combine with single-stranded DNA modified reduced graphene oxide nanocomposites by electrostatic interactions. The modification of single-stranded DNA endowed the reduced graphene oxide with favorable biocompatibility and provided the preferable surface with negative charge for further assembling of gold nanoparticles to obtain gold nanoparticles/single-stranded DNA modified reduced graphene oxide nanocomposites with better conductivity, larger specific surface area, biocompatibility and electrocatalytic characteristics. The as-prepared nanocomposites were applied as substrates for the construction of cholesterol oxidase modified electrode and well realized the direct electron transfer between the enzyme and electrode. The modified gold nanoparticles could further catalyze the products of cholesterol oxidation catalyzed by cholesterol oxidase, which was beneficial to the enzyme-catalyzed reaction. The as-fabricated bioelectrode exhibited excellent electrocatalytic performance for the cholesterol with a linear range of 7.5−280.5 μmol·L⁻¹, a low detection limit of 2.1 μmol·L⁻¹, good stability and reproducibility. Moreover, the electrochemical biosensor showed good selectivity and acceptable accuracy for the detection of cholesterol in human serum samples.     

葡糖氧化酶修饰碳纤维电极

研究了碳纤维电极经预处理后与葡糖酶的偶联行为，电化学氧化处理碳纤维的最佳时间是２ｍｉｎ，此法制得的碳纤维葡糖酶修饰电极活性期可达２个月以上。     

胆红素氧化酶的生物电化学特性研究进展

从胆红素氧化酶的结构、来源、生物电催化的反应机制（铜离子活性中心的氧化还原电势、直接和介体参与的电子传递）、修饰电极的材料、固定化技术以及在生物燃料电池中的应用等方面介绍了胆红素氧化酶,提出了胆红素氧化酶的结构与来源、生物电催化,胆红素氧化酶燃料电池和胆红素氧化酶在电化学中的应用。     

A new amperometric glucose biosensor based on platinum nanoparticles/polymerized ionic liquid-carbon nanotubes nanocomposites

A new amperometric glucose biosensor has been developed based on platinum (Pt) nanoparticles/polymerized ionic liquid-carbon nanotubes (CNTs) nanocomposites (PtNPs/PIL-CNTs). The CNTs was functionalized with polymerized ionic liquid (PIL) through directly polymerization of the ionic liquid, 1-vinyl-3-ethylimidazolium tetrafluoroborate ([VEIM]BF₄), on carbon nanotubes and then used as the support for the highly dispersed Pt nanoparticles. The electrochemical performance of the PtNPs/PIL-CNTs modified glassy carbon (PtNPs/PIL-CNTs/GC) electrode has been investigated by typical electrochemical methods. The PtNPs/PIL-CNTs/GC electrode shows high electrocatalytic activity towards the oxidation of hydrogen peroxide. Taking glucose oxidase (GOD) as the model, the resulting amperometric glucose biosensor shows good analytical characteristics, such as a high sensitivity (28.28 μA mM⁻¹ cm⁻²), wide linear range (up to 12 mM) and low detection limit (10 μM).     

Bioconjugates of Glucose Oxidase and Gold Nanorods Based on Electrostatic Interaction with Enhanced Thermostability

Bioconjugates made up of an enzyme and gold nanorods (GNRs) were fabricated by electrostatic interactions (layer-by-layer method, LBL) between anionic glucose oxidase (GOD) and positively charged GNRs. The assembled processes were monitored by UV–Vis spectra, zeta potential measurements, and transmission electron microscopy. The enzyme activity assays of the obtained bioconjugates display a relatively enhanced thermostability behavior in contrast with that of free enzyme. Free GOD in solution only retains about 22% of its relative activity at 90 °C. Unexpectedly, the immobilized GOD on GNRs still retains about 39.3% activity after the same treatment. This work will be of significance for the biologic enhancement using other kinds of anisotropic nanostructure and suggests a new way of enhancing enzyme thermostability using anisotropic metal nanomaterials.     

Glucose-Sensitive Liposomes Incorporating Hydrophobically Modified Glucose Oxidase

Glucose-sensitive liposomes were prepared by incorporating hydrophobically modified glucose oxidase (EC 1.1.3.4.) into the liposomal bilayer of dioleoylphosphatidylethanolamine and cholesteryl hemisuccinate. For the release test, calcein, a fluorescence marker, was entrapped in the liposomes. The liposomes were stable under neutral conditions in terms of calcein release but an extensive release was observed under acidic conditions. In the experiment of glucose concentration-dependent calcein release, no release was observed for 180 min when the suspension of liposome was free of glucose. With a glucose concentration of 50 mg/dL, no appreciable amount of calcein was released for the first 20 min, and then the release rate was accelerated. At 200 mg/dL glucose concentration which is diagnostic and indicative for insulin-dependent diabetes, the lag time of calcein release became shorter and a faster response was obtained. When glucose concentration further increased to 400 mg/dL, the calcein release rate and the degree of release in 180 min were almost the same as the values when the glucose concentration was 200 mg/dL. The glucose concentration-dependent release is due to pH change, since the suspension of liposomes became acidic during the release experiments.     

Immobilization of glucose oxidase in the regenerated silk fibroin membrane: Characterization of the membrane structure and its application to an amperometric glucose sensor employing ferrocene as electron shuttle

The structural changes of the regenerated silk fibroin membranes for immobilizing glucose oxidase were characterized with FT-IR spectra. The results of electronic absorption spectra and scanning electron microscopy illustrated that the glucose oxidase in the membranes existed in aggregates. The blend membranes exhibited an island-like structure, attributable to the incompatible and weak intermolecular interactions between regenerated silk fibroin and glucose oxidase. The glucose sensor was constructed by combining glucose oxidase immobilized in regenerated silk fibroin membrane with an Eastman-AQ-ferrocene modified electrode. The advantages of the mediator include high stability and the ability to use a less positive potential for increased selectivity.     

An ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core–shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle

The paper reported an ultrasensitive electrochemical biosensor for glucose which was based on CdTe-CdS core–shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since efficient electron transfer between glucose oxidase and the electrode was achieved, the biosensor showed high sensitivity (5762.8 nA nM⁻¹ cm⁻²), low detection limit (S/N = 3) (3 × 10⁻¹² M), fast response time (0.045 s), wide calibration range (from 1 × 10⁻¹¹ M to 1 × 10⁻⁸ M) and good long-term stability (26 weeks). The apparent Michaelis–Menten constant of the glucose oxidase on the medium, 5.24 × 10⁻⁶ mM, indicates excellent bioelectrocatalytic activity of the immobilized enzyme towards glucose oxidation. Moreover, the effects of omitting graphene-gold nanocomposite, CdTe-CdS core–shell quantum dot and gold nanoparticle were also investigated. The result showed sensitivity of the biosensor is 7.67-fold better if graphene-gold nanocomposite, CdTe-CdS core–shell quantum dot and gold nanoparticle are used. This could be ascribed to improvement of the conductivity between graphene nanosheets due to introduction of gold nanoparticles, ultrafast charge transfer from CdTe-CdS core–shell quantum dot to graphene nanosheets and gold nanoparticle due to unique electrochemical properties of the CdTe-CdS core–shell quantum dot and good biocompatibility of gold nanoparticle for glucose oxidase. The biosensor is of best sensitivity in all glucose biosensors based on graphene nanomaterials up to now and has been satisfactorily applied to determination of the glucose in human saliva samples.     

乙二醛氧化酶的研究进展

乙二醛氧化酶是一类黄孢原毛平革菌木质素降解酶系中重要的H2O2供体。近年来,随着对木质素降解酶系的深入研究,乙二醛氧化酶的神秘面纱也逐渐被人们揭开。     

Neodymium (III) hexacyanoferrate (II) nanoparticles induced by enzymatic reaction and their use in biosensing of glucose

The formation of neodymium (III) hexacyanoferrate (II) (NdHCF) nanoparticles (NPs) on the surface of carbon-paste electrode induced by enzymatic reaction was described and characterized. The conditions for biosensing of glucose were optimized through various experiments. Results showed that the optimized condition of the glucose oxidase (GOx)-induced NdHCF NPs for the biosensing of glucose were 2.0 mM Nd³⁺, 40.0 mM Fe(CN)₆³⁻ and 20 μg/mL GOx. The biocatalyzed generation of NdHCF NPs in the presence of O₂/glucose and GOx enabled the development of an electrochemical biosensor for glucose. Furthermore, this system avoids the interferences from other species for the biosensing of glucose.