碳纳米管负载铂颗粒酶电极葡萄糖传感器

以碳纳米管负载纳米铂颗粒修饰玻碳电极 (CNT Pt/GCE)为基底 ,用明胶固定葡萄糖氧化酶(GOD) ,构建了电流型葡萄糖生物传感器 (GOD/CNT Pt/GCE)。在实验中 ,GOD/CNT Pt/GCE显示了良好的分析性能 ,与常规铂电极葡萄糖传感器 (GOD/Pt)相比较 ,测定葡萄糖的检出限从 6 .7× 10 -3 mol/L下降到8.3× 10 -4mol/L ;工作电位从 0 .6 5V下降至 0 .4 5V ;响应时间从 30s下降至 5s左右。实验结果表明 ,具有高度电催化活性的CNT Pt/GCE可作为酶传感器的一种新型基体电极。     

一种新型酶生物燃料电池阳极构建及性能研究

通过酸化碳纳米管(CNTs)和β-环糊精(β-CD)之间的范德华力作用, 实现CNTs的β-CD功能化. β-CD具有内腔疏水、外壁亲水的环状结构, 其内腔容易与二茂铁(Fc)形成稳定的主客体包合结构, 实现Fc在碳纳米管上的高效固载; 再将CNTs-β-CD-Fc复合物与葡萄糖氧化酶(GOD)混合, 采用戊二醛实现酶分子间的交联, 形成GOD/CNTs-β-CD-Fc复合物, 然后将其涂覆到玻碳电极(GC)上, 得到一种新型的酶生物燃料电池阳极(GOD/CNTs-β-CD-Fc/GC). 采用同步热分析法、傅里叶变换红外光谱和透射电子显微镜对所制备的CNTs-β-CD-Fc复合物进行了表征, 采用循环伏安法研究了GOD/CNTs-β-CD-Fc/GC电极对葡萄糖氧化的催化性能. 结果表明: 在同等实验条件下, 没有固载Fc的GOD/CNTs- β-CD/GC电极基本无催化电流, 而GOD/CNTs-β-CD-Fc/GC电极表现出比GOD/CNTs-Fc/GC电极更为优越的电催化性能. 进一步以GOD/CNTs-β-CD-Fc/GC电极或GOD/CNTs-Fc/GC电极为酶阳极, 商用催化剂E-TEK Pt/C电极(E-TEK Pt/C/GC)为阴极, 构建葡萄糖/氧气生物燃料电池(EBFC), 结果表明前者的最大功率密度(33 μW·cm^-2, 0.18 V)几乎是后者的三倍(11.7 μW·cm^-2, 0.16 V). 通过记录开路电位随时间的变化研究了EBFC的稳定性, 以GOD/CNTs-β-CD-Fc/GC电极为阳极的EBFC在连续工作9 h后仍保留了92%的开路电位, 表明该电池具有良好的连续工作稳定性. 我们提出的这种新型生物燃料电池阳极的构造方法, 为构建高性能、高稳定性的葡萄糖/氧气EBFC提供了新的思路.     

亲水金和憎水二氧化硅纳米颗粒对葡萄糖生物传感器响应灵敏度的增强作用

用亲水金、憎水二氧化硅纳米颗粒固定葡萄糖氧化酶(GOD),采用聚乙烯醇缩丁醛(PVB)为辅助固酶膜基质来制备葡萄糖生物传感器,并考察了亲水金、憎水二氧化硅纳米颗粒对酶电极电流响应的影响.实验表明,引入纳米粒子可显著增强电极响应灵敏度.并对两种不同性质纳米颗粒所起作用的可能机理进行讨论,从理论和实验上证明了纳米颗粒对固定酶的作用.为制备有实用价值的葡萄糖生物传感器提供了可供参考的实验和理论依据.     

镀金和碳纳米管修饰金电极上吸附态葡萄糖氧化酶比活性的EQCM研究

采用石英晶体微天平(EQCM)技术监测了裸金电极、镀金和碳纳米管修饰金电极上葡萄糖氧化酶(GOD)的吸附过程. 通过EQCM测量吸附固定的GOD质量, 并实时检测酶反应产物H2O2的氧化电量, 求算了各表面上吸附态GOD的比活性(ESAi). 结果表明, 各表面上均可吸附一定的GOD, 且吸附态GOD均有一定的酶活性; 修饰CNTs可增大酶吸附量和酶电极对葡萄糖的响应电流, 但ESAi随CNTs修饰量的增大而降低; Au电极上电镀金后, 酶吸附量和酶电极对葡萄糖的响应电流亦增大, 但ESAi与裸金电极上的基本一致.     

基于花状铂纳米颗粒构建的电致化学发光免疫传感器用于检测载脂蛋白A1

采用一锅合成法制备了新型的具有大比表面积的花状铂纳米颗粒（PtNFs）,并构建了一个高灵敏电致化学发光（ECL）免疫传感器用于检测载脂蛋白A1（Apo-A1）. 该PtNFs用于吸附二抗（anti-Apo-A1）,并用葡糖糖氧化酶（GOD）封闭其表面的非特异性位点,最终制备了PtNFs@anti-Apo-A1@GOD信号探针. 当Apo-A1存在时,通过夹心免疫反应将制备的信号探针捕获于电极表面,并将所制得的电极置于含有葡萄糖的过硫酸根底液中检测. GOD催化葡萄糖产生H₂O₂,H₂O₂在PtNFs的催化下分解并在电极表面原位产生O₂,所产生的O₂能够催化过硫酸根-氧气体系的电致化学发光反应,放大发光信号,提高检测灵敏度. 该传感器在0.1ng•mL^-1 ~ 100 ng•mL^-1范围内对Apo-A1有良好的线性响应,检测下限达到0.03ng•mL^-1,有望应用于临床分析诊断.     

纳米ZnO增强葡萄糖生物传感器的制备和应用

为提高葡萄糖生物传感器的灵敏度,以纳米ZnO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),用戊二醛进行交联,制成葡萄糖生物传感器。实验结果表明,GOD可牢固地固定在电极表面,在相同葡萄糖浓度下,加入纳米颗粒的电极的电流响应值比未加颗粒的高约100倍,电极重复使用46次后电流响应值仅下降到初始的70%。电极制备方法简单,易于操作。同时对温度、溶液pH值以及溶剂对电极的影响进行了研究,获得了最优的实验条件。     

甘氨酸为络合剂时钯和葡萄糖氧化酶的电化学共沉积研究

甘氨酸和Pd(NH3 ) 2 Cl2 组成镀液 ,用于钯和葡萄糖氧化酶 (GOD)的电化学共沉积以制备金属化酶电极、UV/V光谱实验表明甘氨酸能与Pd2 + 离子发生络合作用 ,并使镀液在一定 pH范围内具有较稳定的化学组成 .伏安法实验证实甘氨酸的存在降低了Pd的沉积电位 ,有利于防止钯氢化合物的形成 .讨论了钯和GOD电化学共沉积的合适条件 .     

纳米级微带金电极上葡萄糖氧化酶的固定.性质及应用

实现了葡萄糖氧化酶以及葡萄糖氧化酶和电子传递媒体Fe(CN)^3^-~6同时在纳米级微带电极上的固定,用红外光谱和循环伏安对GOD/PPy微电极进行了表征, 研究了微带金电极上聚吡咯恒电位形成过程的动力学及葡萄糖氧化酶对其动力学过程的影响,探讨了微酶电极GOD/Fe(CN)^3^-~6/PPy对葡萄糖氧化的催化作用, 考察了PPy膜厚度和溶液中氧的存在对GOD/Fe(CN)^3^-~6/PPy微电极测定葡萄糖的影响.     

离子液体中水热合成Pt-Pd/MWCNTs和Pd/MWCNTs催化剂

采用水热合成法, 以离子液体1-乙基-3-甲基咪唑四氟硼酸盐(C₆H₁₁BF₄N₂, EMIBF₄)为溶剂制备了Pt-Pd/MWCNTs(Multi-walled carbon nanotubes)和Pd/MWCNTs催化剂. X射线衍射(XRD)和X射线能量散射谱(EDS)测试证明了Pt-Pd合金和Pd纳米颗粒在MWCNTs的表面生成. 透射电子显微镜(TEM)照片不仅证明了在MWCNTs表面Pt-Pd, Pd纳米颗粒的生成, 而且还表明样品颗粒的平均粒径约为4 nm. 循环伏安(CV)和交流阻抗(EIS)测试表明, 在碱性环境下, 乙醇在Pt-Pd/MWCNTs和Pd/MWCNTs修饰的玻碳(GC)电极上均能发生氧化反应, 与Pd/MWCNTs修饰的电极相比, 在Pt-Pd/MWCNTs上乙醇的起峰电位负移了大约200 mV, 且具有更高的氧化峰电流值.     

炭气凝胶纳米颗粒固定葡萄糖氧化酶的直接电化学

利用间苯二酚和甲醛在碱性环境下制备炭气凝胶(CA), 通过扫描电镜(SEM)、透射电镜(TEM)、比表面积测试Brunauer-Emmett-Teller (BET)等方法分析载体的形貌结构; 以CA为载体通过吸附法固定葡萄糖氧化酶(GOD)并修饰玻碳(GC)电极, 得到GOD/CA/GC电极. 在0.1 mol·L^-1磷酸盐缓冲溶液中, 利用循环伏安法研究了GOD/CA/GC 电极的直接电化学行为和对葡萄糖的催化性能. 结果表明, 以CA为载体可以很好地固定GOD并保持其生物活性, 在无任何电子媒介体存在时, GOD在电极上实现了直接电子转移, GOD/CA/GC电极对葡萄糖具有很好的电催化性能.     

Direct electrochemistry study of glucose oxidase on Pt nanoparticle-modified aligned carbon nanotubes electrode by the assistance of chitosan–CdS and its biosensoring for glucose

Aligned carbon nanotubes (ACNTs) electrode has been developed for the direct protein electrochemistry and enzyme-biosensor study involving two types of nanoparticles. Pt nanoparticles (Pt_nano) were electro-modified on the ACNTs’ each tube, greatly increasing the electrode surface area for locating protein and also its electronic transfer ability. Glucose oxidase (GOD) with chitosan (CS) and CdS nanoparticles electrochemically coated on each tube of ACNTs–Pt_nano by the electrodeposition reaction of CS when pH value passing its pKa. The CdS nanoparticles between ACNTs electrode and GOD have stimulated the GOD’s direct electron transfer during its redox reaction of FAD/FADH₂. The CS–GOD–CdS/ACNTs–Pt_nano electrode also offer sensitive response to the substrate of glucose with detection limit of 46.8 μM (S/N = 3) and apparent Michaelis–Menten constant of 11.86 mM.     

铂纳米颗粒修饰直立碳纳米管电极的葡萄糖生物传感器

基于Pt纳米颗粒修饰直立的碳纳米管电极制备了葡萄糖生物传感器.铂纳米颗粒是利用电位脉冲沉积法修饰到直立碳纳米管上的,可以增强电极对酶反应过程当中产生的过氧化氢的催化行为.用扫描电镜和透射电镜观察了直立碳纳米管在修饰Pt纳米颗粒前后的形态.该酶电极对葡萄糖的氧化表现出很好的响应,线性范围为1×10-5～7×10-3mol/L,响应时间小于5s,并且有很好的重现性.     

Amperometric Glucose Biosensor Based on Platinum Nanoparticles Combined Aligned Carbon Nanotubes Electrode

A sensitive amperometric glucose biosensor based on platinum nanoparticles (PtNPs) combined aligned carbon nanotubes (ACNTs) electrode was investigated. PtNPs which can enhance the electrocatalytic activity of the electrode for electrooxidating hydrogen peroxide by enzymatic reaction were electrocrystallized on 4‐aminobenzene monolayer‐grafted ACNTs electrode by potential‐step method. These PtNPs combined ACNTs' (PtNPs/ACNTs) surfaces were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The highly dispersed PtNPs on ACNTs can be obtained. The enzyme electrode exhibits excellent response performance to glucose with linear range from 1×10^?5–7×10^?3 mol L^?1 and fast response time within 5 s. Furthermore, this glucose biosensor also has good reproducibility. It is demonstrated that the PtNPs/ACNTs electrode with high electrocatalytic activity is a suitable basic electrode for preparing enzyme electrodes.     

Kinetic analysis of superoxide anion radical-scavenging and hydroxyl radical-scavenging activities of platinum nanoparticles

There are few reports on the physiological effects of metal nanoparticles (nps), especially with respect to their functions as scavengers for superoxide anion radical (O2(.-)) and hydroxyl radical (.OH). We tried to detect the scavenging activity of Pt nps using a hypoxanthine-xanthine oxidase system for O2(.-) and using a Fenton and a UV/H2O2 system for .OH. Electron spin resonance analysis revealed that 2 nm particle size Pt nps have the ability to scavenge O2(.-) and .OH. The calculated rate constant for the O2(.-)-scavenging reaction was 5.03 +/- 0.03 x 10(7) M (-1) s (-1). However, the analysis of the Fenton and UV/H 2O 2 system in the presence of Pt nps suggested that the .OH-scavenging reaction cannot be determined in both systems. Among particle sizes tested from 1 to 5 nm, 1 nm Pt nps showed the highest O2(.-)-scavenging ability. Almost no cytotoxicity was observed even after adherent cells (TIG-1, HeLa, HepG2, WI-38, and MRC-5) were exposed to Pt nps at concentrations as high as 50 mg/L. Pt nps scavenged intrinsically generated reactive oxygen species (ROS) in HeLa cells. Additionally, Pt nps significantly reduced the levels of intracellular O2(.-) generated by UVA irradiation and subsequently protected HeLa cells from ROS damage-induced cell death. These findings suggest that Pt nps may be a new type of antioxidant capable of circumventing the paradoxical effects of conventional antioxidants.     

Amperometric biosensor based on thermally activated polymer-stabilized metal nanoparticles

Polymer-stabilized Pd nanoparticles on carbon support were synthesized by a low thermal procedure that does not involve the utilization of a reducing agent such as NaBH₄ or hydrogen gas for the formation of the metallic nanoparticles. The Pd-catalyzed graphite particles were then mixed with known amounts of glucose oxidase (GOx) enzyme and Nafion to prepare a GOx-immobilized ink. A glassy carbon electrode (GCE) modified with the GOx ink was used to evaluate the performance of the biosensor electrode. The results of TEM and AFM show that the Pd nanoparticles are uniformly distributed on top of the substrate. Results are presented for sensing glucose through the voltammetric measurement of H₂O₂. Coupled with the simplicity of preparation, the biosensor exhibited high sensitivity and extended linear range for glucose measurement. Further, the electrochemical characteristics of the nanocomposite biosensor were evaluated with respect to the electrochemistry of potassium ferricyanide by cyclic voltammetry. Whereas the presence of polymer and Nafion improved the stability of both the ink and biosensor electrode, the concentration of glucose was measured without interferences from oxygen, ascorbic acid and uric acid because of the Nafion.     

A Membraneless Glucose/O2 Biofuel Cell Based on Pd Aerogels

In this study, we introduce the first membraneless glucose/O₂ biofuel cell using Pd‐based aerogels as electrode materials. The bioanode was fabricated with a coimmobilized mediator and glucose oxidase for the oxidation of glucose, in which ferrocenecarboxylic acid was integrated into a three‐dimensional porous beta‐cyclodextrin‐modified Pd aerogel to mediate the bioelectrocatalytic reaction. Bilirubin oxidase and Pd–Pt alloy aerogel were confined to an electrode surface, which realized the direct bioelectrocatalytic function for the reduction of O₂ to H₂O with a synergetic effect at the biocathode. By employing these two bioelectrodes, the assembled glucose/O₂ biofuel cell showed a maximum power output of 20 μW cm^?2 at 0.25 V.     

Amperometric Glucose Biosensor Based on Pt‐Pd Nanoparticles Supported by Reduced Graphene Oxide and Integrated with Glucose Oxidase

A novel glucose biosensor was developed based on the immobilization of glucose oxidase (GOx) on reduced graphene oxide incorporated with electrochemically deposited platinum and palladium nanoparticles (PtPdNPs). Reduced graphene oxide (RGO) was more hybridized by chemical and heat treatment. Bimetallic nanoparticles were deposited electrochemically on the RGO surface for potential application of the Pd? Pt alloy in biosensor preparation. The as‐prepared hybrid electrode exhibited high electrocatalytic activities toward H₂O₂, with a wide linear response range from 0.5 to 8 mM (R²=0.997) and high sensitivity of 814×10^?6 A/mMcm². Furthermore, glucose oxidase with active material was integrated by a simple casting method on the RGO/PdPtNPs surface. The as‐prepared biosensor showed good amperometric response to glucose in the linear range from 2 mM to 12 mM, with a sensitivity of 24×10^?6 A/mMcm², a low detection limit of 0.001 mM, and a short response time (5 s). Moreover, the effect of interference materials, reproducibility and the stability of the sensor were also investigated.     

Electrochemical Behavior of Glucose Oxidase Immobilized on Pd‐Nanoparticles Decorated Ionic Liquid Derived Fibrillated Mesoporous Carbon

Pd nanoparticles with an average diameter of 5 nm were decorated on the surface of ionic liquid derived fibrillated mesoporous carbon (IFMC) to prepare a novel nano‐hybrid material (Pd@IFMC). Thereafter, glucose oxidase was immobilized on Pd@IFMC modified glassy carbon electrode to fabricate an enzymatic glucose biosensor. A pair of well‐defined redox peaks was recorded for direct electron transfer of the immobilized glucose oxidase at the formal potential of ? 0.418 V with a peak to peak separation of 25 mV. Electron transfer rate constant of was calculated to be 14.6 s^?1. The response of fabricated biosensor was linear towards glucose concentration.     

Direct Electrochemistry and Electrocatalysis of Hemoglobin on Aligned Carbon Nanotubes Based Electrodes Modified with Au Nanoparticles and SiO2 Gel

Here we report on the preparation and characterization of new electrodes based on aligned carbon nanotubes (ACNTs) for hemoglobin (Hb) electrochemistry and electrocatalysis. The ACNTs are obtained by a thermal chemical vapor deposition method under normal pressure. Then the electrodes are elaborated by first sputtering a thin Au film (thickness of 200 nm) onto the top of the ACNTs, and then removing the Au layer/ACNTs from the quartz substrate with the aide of hydrofluoric acid (HF) treatment. Field emission scanning electron microscopy (FESEM) demonstrates that after nitric acid (HNO₃) treatment, the nanotubes of the removed Au layer are totally tip‐opened, purified and organized in a perfect vertically aligned architecture. The final ACNTs electrode is obtained by attaching the Au layer of ACNTs onto a glassy carbon electrode. Then the electrode was modified to act as a matrix for hemoglobin (Hb) immobilization and as an electrode for Hb electroanalysis by the assistance of Au nanoparticles (AuNPs) and SiO₂ gel. Due to the individual specific effects of AuNPs, SiO₂ gel and ACNTs, the resulting SiO₂/Hb‐AuNPs/ACNTs electrode showed good direct electrochemistry of Hb with an apparent Michaelis? Menten constant of 0.44 mM. The electrode showed an excellent electrocatalytic activity towards H₂O₂, possessing a linear range from 40 µM to 4 mM and the detection limit was 22 µM based on a signal to noise ratio of 3.     

基于Nafion/碳纳米粒子修饰的葡萄糖传感器

采用滴涂法制备了Nafion/碳纳米粒子复合物修饰玻碳电极,该电极对H2O2具有良好的电催化氧化性能。还利用滴涂法制备了Nafion/碳纳米粒子复合物包裹的葡萄糖酶电化学生物传感器,该生物传感器对葡萄糖有着良好的电催化作用。应用该传感器对葡萄糖进行了检测,检测线性范围为2.0×10-6～6.0×10-3mol/L,检出限为1.6×10-6mol/L(S/N=3),实验结果表明该传感器具有良好的稳定性、重现性和抗干扰能力。对小鼠血清样品中的葡萄糖进行检测,结果令人满意。