Fabrication of a novel electrochemiluminescence glucose biosensor using Au nanoparticles decorated multiwalled carbon nanotubes

Au nanoparticles (nanoAu) with an average diameter of 60 nm were decorated on the surface of multiwalled carbon nanotubes to prepare MWCNTs-nanoAu nano-hybrids. The MWCNTs-nanoAu nano-hybrids were cast on the surface of a glassy carbon electrode and were then further modified with a layer comprising glucose oxidase and chitosan to fabricate a novel electrochemiluminescence (ECL) glucose biosensor. The biosensor showed a remarkably improved electrocatalytic activity towards luminol oxidation and significant improvement in its ECL response. The proposed ECL biosensor exhibited excellent performance for glucose detection with a wide linear range (1-1000 μM), low detection limit (0.5 μM), excellent reproducibility (0.5%) and satisfactory selectivity.     

Performance of glucose biosensor based on oxygen electrode in physiological fluids and at body temperature

A potentially implantable glucose biosensor for continuous monitoring of glucose levels in diabetic patients has been developed. The glucose biosensor is based on an amperometric oxygen electrode and glucose oxidase immobilized on carbon powder held in the form of a liquid suspension. The enzyme material can be replaced (the sensor recharged) without sensor disassembly. Diffusion membranes made of silastic coatings over a microporous polycarbonate membrane are used. Calibration curves of the sensors in phosphate buffer solution and in undiluted blood plasma at body temperature have been obtained. The reproducibility of the sensor response in serum at body temperature is demonstrated. The sensors have a stable signal during storage and continuous operation at body temperature for a period of at least one month.     

A novel photometric glucose biosensor based on decolorizing of silver nanoparticles

A novel glucose biosensor based on chromophore (silver nanoparticles) decolorizing for the photometric determination of glucose was developed. Silver nanoparticles are directly synthesized in the sol-gel matrix by a one-step method based on the reduction of the inorganic precursor AgNO₃ and were used for the preparation, characterization and calibration of a highly sensitive and cost-effective localized surface plasmon resonance-based glucose biosensor. In the presence of glucose oxidase (GOx) and due to the enzyme-substrate (glucose) reaction, H₂O₂ was produced and silver nanoparticles in the sol-gel glass have the ability for the decomposition of hydrogen peroxide. Due to the degradation of silver nanoparticles a remarkable change in the localized surface plasmon resonance absorbance strength could be observed which have been monitored as a suitable signal for determination of substrate concentration. Beer's law is obeyed in the range from 50 to 800 mg/L glucose and the limit of detection is 23 mg/L. The proposed optical biosensor has been successfully applied to the determination of glucose in various real samples.     

基于碳纳米管固定葡萄糖氧化酶的ECL葡萄糖传感器的制备

将葡萄糖氧化酶(GOD)固定在多壁碳纳米管(MWCNTs)修饰电极(ME)上,GOD催化氧化葡萄糖生成过氧化氢,并使鲁米诺产生电致化学发光(ECL),据此构建了一种新型ECL葡萄糖传感器.结果表明:CNTs修饰的电极对鲁米诺和H2O2反应具有显著的电催化活性和增敏效果.该传感器对葡萄糖检测的线性范围为0.01～10.0...     

A miniaturized glucose biosensor based on the coimmobilization of glucose oxidase and ferrocene perchlorate in nafion at a microdisk platinum electrode

A miniaturized glucose biosensor based on the coimmobilization of Fc⁺ (ferrocene perchlorate)/GOD (glucose oxidase) in nafion film at the surface of a microdisk platinum electrode was fabricated and successfully used for the amperometric determination of glucose. The influences of various experimental conditions, including the relative amounts of glucose oxidase in diluted nafion aqueous solution, the concentration of ferrocene perchlorate and oxygen etc., were investigated in this paper. Ferrocene perchlorate as a redox mediator could catalyze the oxidation of the generated H₂O₂ based on the enzymatic reaction of glucose in the presence of glucose oxidase and oxygen at a favorable lower working potential (ca. 0.25 V vs. SCE). Moreover, it could also oxidize the reduced flavin adenine dinucleotide (FADH₂) of glucose oxidase directly in anaerobic environment. The response time and the detection limit under an optimal parameters were 2 min and 1 × 10⁻⁵ M, respectively. The interferences of ascorbic acid and uric acid could be obviously reduced because of the ion-selective characteristics of nation film and a favorable lower working potential. From the Michealis-Menten analysis, the apparent Michaelis constants for glucose and the maximum limiting currents determined were 10.7 mM and 5.1 nA for the incorporation of Fc⁺ in 1.00 mM Fc⁺ solution, 7.06 mM and 5.85 nA in 2.00 mM Fc⁺, respectively. Moreover, using water instead of organic solvents for nafion dilution made this enzyme electrode exhibit a good stability and reproducibility for a long-term use.     

Adsorption of glucose oxidase at platinum-multiwalled carbon nanotube-alumina-coated silica nanocomposite for amperometric glucose biosensor

Glucose oxidase (GOx) has been immobilized in platinum-multiwalled carbon nanotube-alumina-coated silica (Pt-MWCNT-ACS) nanocomposite modified glassy carbon electrode by adsorption to provide a novel amperometric glucose biosensor. The morphology, nature, and performance of the resulting GOx-Pt-MWCNT-ACS nanobiocomposite modified glassy carbon electrode were characterized by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry, and amperometry. The influence of various experimental conditions was examined for the determination of the optimum analytical performance. The optimized glucose biosensor displayed a wide linear range of up to 10.5 mM, a high sensitivity of 113.13 mA M⁻¹ cm⁻², and a response time of less than 5 s. The sensitivity for the determination of glucose at the GOx-Pt-MWCNT-ACS nanobiocomposite modified glassy carbon electrode is better than at common GOx-Pt-CNT nanobiocomposite modified electrodes. The proposed biosensor has good anti-interferent ability and long-term storage stability after coating with Nafion, and it can be used for the determination of glucose in synthetic serum.     

An amperometric glucose biosensor based on layer-by-layer GOx-SWCNT conjugate/redox polymer multilayer on a screen-printed carbon electrode

An amperometric glucose biosensor based on a multilayer made by layer-by-layer assembly of single-walled carbon nanotubes modified with glucose oxidase (GOx-SWCNT conjugates) and redox polymer (PVI-Os) on a screen-printed carbon electrode (SPCE) surface was developed. The SPCE surface was functionalized with a cationic polymer by electrodeposition of the PVI-Os, followed by alternating immersions in anionic GOx-SWCNT conjugate solutions and cationic PVI-O solutions. The purpose is to build a multilayer structure which is further stabilized through the electrodeposition of PVI-Os on the multilayer film. The electrochemistry of the layer-by-layer assembly of the GOx-SWCNT conjugate/PVI-Os bilayer was followed by cyclic voltammetry. The resultant glucose biosensor provided stable and reproducible electrocatalytic responses to glucose, and the electrocatalytic current for glucose oxidation was enhanced with an increase in the number of bilayers. The glucose biosensor displayed a wide linear range from 0.5 to 8.0 mM, a high sensitivity of 32 μA mM⁻¹ cm⁻², and a response time of less than 5 s. The glucose biosensor proved to be promising amperometric detectors for the flow injection analysis of glucose.     

基于铂纳米颗粒修饰碳纳米管Nafion膜电极的葡萄糖传感器

将分散在Nafion溶液中的多壁碳纳米管(MWNT)修饰玻碳电极(GCE),再在该膜上电沉积一层铂纳米粒子,制成铂纳米颗粒修饰的碳纳米管Nafion膜电极(Nafion-MWNT-Pt/GCE),并吸附固定葡萄糖氧化酶(GOD),构建电流型葡萄糖生物传感器。考察了Nafion-MWNT-Pt/GCE的电化学特性,发现沉积铂纳米粒子后,Fe(CN)6-3/-4电对在Nafion-MWNT-Pt/GCE上的氧化峰和还原蜂之间的电势差(ΔE)为179mV,小于未修饰铂纳米粒子的碳纳米管Nafion膜电极的ΔE(190mV),表明碳纳米管上电沉积的铂纳米粒子可加速电极的电子传递,电化学反应具有良好的可逆性。此外,铂纳米粒子尚具有良好的催化H2O2氧化的特性,H2O2在Nafion-MWNT-Pt/GCE上的计时电流响应明显增大。基于Nafion-MWNT-Pt/GCE的葡萄糖生物传感器显示了良好的传感性能,其检测线性范围为2.1×10-5～7.6×10-3mol/L,检测下限为1.0×10-6mol/L。     

碳纳米管-铂纳米颗粒修饰金电极用于葡萄糖生物传感器的研究

用交联剂戊二醛把葡萄糖氧化酶(GOx)固定在多聚赖氨酸(polylysine)修饰的碳纳米管(CNT)上,然后将Nafion和修饰上葡萄糖氧化酶的碳纳米管(CNT-lysine-GOx)混合均匀涂在Pt纳米颗粒修饰的金电极表面制备成葡萄糖传感器。探讨了Pt沉积时间、Nafion中碳纳米管的含量、缓冲液的pH值以及工作电位对电极响应的影响。实验结果表明该传感器具有响应快、稳定性好等优点,催化电流与葡萄糖的浓度在0.1μmol/L～6mmol/L范围内成线性关系,响应时间小于5s。     

Direct electron transfer of glucose oxidase at glassy carbon electrode modified with functionalized carbon nanotubes within a dihexadecylphosphate film

A glassy carbon electrode modified with functionalized multiwalled carbon nanotubes (CNTs) immobilized by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) in a dihexadecylphosphate film was prepared and characterized by cyclic voltammetry and scanning electron microscopy. It was used as a support for FAD or glucose oxidase (GOx) immobilization with EDC/NHS crosslinking agents. Cyclic voltammetry of GOx immobilized onto the surface of CNTs showed a pair of well-defined redox peaks, which correspond to the direct electron transfer of GOx, with a formal potential of −0.418 V vs. Ag/AgCl (3 M KCl) in 0.1 M phosphate buffer solution (pH 7.0). An apparent heterogeneous electron transfer rate constant of 1.69 s⁻¹ was obtained. The dependence of half wave potential on pH indicated that the direct electron transfer reaction of GOx involves a two-electron, two-proton transfer. The determination of glucose was carried out by square wave voltammetry and the developed biosensor showed good reproducibility and stability. The proposed method could be easily extended to immobilize and evaluate the direct electron transfer of other redox enzymes or proteins.     

A novel microbial biosensor based on Circinella sp. modified carbon paste electrode and its voltammetric application

Microbial biosensors have been developed for voltammetric determination of various substances. This paper describes the development of a new biosorption based microbial biosensor for determination of Cu²⁺. The developed biosensor is based on carbon paste electrode consisting of whole cells of Circinella sp. Cu²⁺ was preconcentrated on the electrode surface at open circuit and then cathodically detected with the reduction of Cu²⁺. The voltammetric responses were evaluated with respect to percentage cell loading in the carbon paste, preconcentration time, pH of preconcentration solution, scan rate and interferences. The optimum response was realized by biosensor constructed using 5 mg of dry cell weight per 100 mg of carbon paste in pH 5.5 preconcentration solution. Under the optimum experimental conditions, the developed microbial biosensor exhibited an excellent current response to Cu²⁺ over a linear range from 5.0 × 10⁻⁷ to 1.0 × 10⁻⁵ M (r² = 0.9938) with a detection limit of 5.4 × 10⁻⁸ M (S/N = 3). The microbial biosensor had good sensitivity and reproducibility (R.S.D. 4.3%, n = 6). Finally, the applicability of the proposed microbial biosensor to voltammetric determination of Cu²⁺ in real sample was also demonstrated and validated with atomic absorption spectrophotometric (AAS) method.     

Amperometric glucose biosensor based on integration of glucose oxidase with platinum nanoparticles/ordered mesoporous carbon nanocomposite

This article reports a new amperometric glucose biosensor based on ordered mesoporous carbon (OMC) supported platinum nanoparticles (Pt/OMC) modified electrode. The Pt/OMC nanocomposite modified electrode exhibited excellent electrocatalytic activities towards the reduction and oxidation of H₂O₂ as well. This feature allowed us to use it as bioplatform on which glucose oxidase (GOD) was immobilized by entrapment in electropolymerized pyrrole film for the construction of the glucose biosensor. The biosensor showed good analytical performances in terms of low detection (0.05 mM), high sensitivity (0.38 μA/mM) and wide linear range (0.05-3.70 mM). In addition, the effects of pH value, applied potential, electroactive interference and the stability of the biosensor were discussed. The applicability to blood analysis was also evaluated.     

A printable glucose sensor based on a poly(pyrrole)-latex hybrid material

A printable glucose sensor was obtained by immobilisation of glucose oxidase onto the surface of poly(pyrrole)-coated latex spheres, which were mixed with a conducting ink. The obtained hybrid material was able to amperometrically detect glucose under aerobic as well as anaerobic conditions, without the use of electron mediators. Since all of the steps involved in the preparation of this latex-poly(pyrrole)-based ink are performed in solution, in-expensive mass production will be possible. A possible mechanism for this sensor is proposed based on the direct communication between the enzyme and the conducting polymer under anaerobic conditions.     

Fiber optic glucose sensor based on bionanofilms

In this paper a glucose fiber optic biosensor based on electrostatic self-assembly adsorption technique is proposed. Up to 35 bilayers biofilm was achieved from alternate deposition of enzyme glucose dehydrogenase and polyelectrolytes polyethyleneimine and poly(sodium 4-styrenesulfonate). The layer thickness was characterized using an in situ optical near infrared interferometry method, which showed formation of nanoscale multilayer structure as a function of alternate adsorption cycles. Experiments showed highly efficient adsorption. The catalytic effect of the multilayer film on the reduction of nicotinamide adenine dinucleotide was studied utilizing ultraviolet fiber optic spectroscopy. The performance of this nanobiofilm onto both the cleaved end of an optical fiber pigtail and a tapered optical fiber structure were compared. As a result enzymes kept their activities after immobilization; the biosensor showed high sensitivity and stability during storage.     

丝网印刷电极的电化学发光生物传感器

对丝网印刷电极及其应用于电化学发光检测的功能化及信号放大修饰进行综述,归纳了该检测体系在抗体、核酸、氧化酶底物、肿瘤细胞、病原菌、抗生素等物质检测中的应用,最后对该领域的发展进行了展望.     

基于半胱氨酸／PDDA／纳米金共修饰的过氧化氢生物传感器研究

将L-半胱氨酸、聚二烯丙基二甲基氯化铵(PDDA)、纳米金及血红蛋白(Hb)自组装到金电极表面,制成了新型过氧化氢生物传感器.采用循环伏安法和计时电流法对该传感器的性能进行了详细研究.实验发现,该传感器增加了酶的吸附量,响应快、稳定性好,对H2O2表现出良好的响应特性.检测范围为4.2×10-7～3.0×10-3 mol/L,检出限为1.4×10-7 mol/L,并具有抗尿酸、抗坏血酸等干扰的特点.     

纳米银／半胱氨酸修饰葡萄糖生物传感器的研究

为优化电流型生物传感器的性能,采用相转移法结合超声波法制备纳米银溶胶,并用透射电镜对其粒径和形态进行了表征.将纳米银/半胱氨酸与葡萄糖氧化酶(GOD)共同修饰在电极表面制成酶电极.结果表明:制备的纳米银粒子近似球形,平均直径为6.27 nm;酶电极的线性响应范围为5.0×10-5～1.5×10-3 mol/L;检出限为7.14×10-6 mol/L(S/N=3);响应时间小于5 s.4℃保存30 d,该电极仍有83.7%的初始响应电流,重复性和稳定性良好.     

以硫堇为介体的纳米金颗粒增强的葡萄糖传感器

研制以纳米金颗粒与聚乙烯缩丁醛(PVB)及葡萄糖氧化酶(GOD)混合制成复合固酶膜基质,制成葡萄糖氧化酶生物传感器.研究了使用硫堇(Thi.)作为电子媒介体对葡萄糖氧化酶电极响应的影响.实验证明,电子媒介体的引入可以大大提高葡萄糖氧化酶电极响应的灵敏度,为制备有实用价值的葡萄糖生物传感器提供了重要的实验依据.     

基于葡萄糖氧化酶-空壳钯修饰的新型葡萄糖传感器

制备了空壳钯纳米粒子,通过TEM对其空壳结构进行了表征。将空壳钯纳米粒子和葡萄糖氧化酶（GOD）修饰在玻碳电极（GC）表面,构建了新型的葡萄糖传感器。空壳钯纳米粒子对过氧化氢（H202）具有良好的催化还原作用,通过检测酶反应产生的H202可检测葡萄糖的浓度。在-0．3V工作电位下,在2．5×10＾－5mol／L到2．7...     

Hybrid phenol biosensor based on modified phenoloxidase electrode

Electrolytic deposition has been widely used to immobilize biomacromolecules, and it is always the most important factor to preserve or even increase an activity of the immobilized protein. We report here simple and rather universal method for the highly efficient immobilization of laccase for amperometric biosensing. Laccase from Cerrena unicolor has been successfully immobilized (electrolytic deposition) on the surface of thin, ordered polythiophene films (3-methylthiophene/3-thiopheneacetic acid/N-heptyl-3,6-bis(2-thiophene)carbazole). Two different compounds capable of mediating laccase-catalyzed reactions have been tested by cyclic voltammetry. They exhibited quasi-reversible electrodic behaviour with formal redox potentials ranging from 68 and 918 mV (E⁰vs. SCE). The immersion of the laccase-coated electrode in solution with substrate generated large catalytic currents easily recorded by cyclic voltammetry at low potential scan rates. Considering the fact, that immobilization strategy showed high efficiency, obtained results suggest that method for phenoloxidase immobilization has a great potential of enabling high throughput fabrication of bioelectronics’ devices.