电化学可控制备溶胶-凝胶薄膜在生物传感器中的应用

构建化学可控、生物兼容性好、有利于界面传质与信号转换的生物传感界面是生物传感研究领域的热点问题和一大挑战.溶胶-凝胶技术在生物传感器领域应用广泛,电化学可控制备的新方法扩大了溶胶-凝胶膜在各个领域的应用前景.该文综述了近年来溶胶-凝胶技术在生物活性物质固定化方面的应用和进展,对比了不同溶胶-凝胶技术在生物传感器应用方面...     

溶胶凝胶技术在生物传感器中的应用进展

溶胶-凝胶材料由于具有制备条件温和、孔径可调、机械刚性、热稳定性好、化学惰性及溶剂中可以忽略的溶胀性等优点而被应用于固定各种生物物质.溶胶凝胶技术是一种新型固定技术,该文综合论述了溶胶凝胶制备过程、影响因素及在生物传感器中的应用发展.     

溶胶-凝胶固定酪氨酸酶电极的研究

研制了用溶胶-凝胶包埋的测酚酪氨酸酶碳糊电极.研究以四乙氧基硅烷(TEOS)为前驱体制备SiO2溶胶-凝胶材料的机理,利用红外光谱法对材料进行了结构表征,确定了制备溶胶-凝胶和制作酶电极的最优化条件.所研制的溶胶-凝胶酪氨酸酶碳糊电极的工作条件为:工作电位-100mV(vs,SCE)、工作pH值5.40、测量时间3 min,电极对苯酚的检测下限为1.00×10-6mol/L,线性区间为1.00×10-6mol/L～1.00×10-4mol/L.相对标准偏差RSD和相对误差RE分别达1.04%和0.002%,此电极对邻甲酚、对苯二酚、邻苯二酚、对氯苯酚都有良好的响应,对邻氨基酚、间苯二酚、对甲苯酚、邻硝基酚、2.4二甲基酚响应不好.有机干扰物苯、甲苯、丙酮、乙酸乙酯、抗坏血酸对它无影响.电极在使用72 h后,电极响应最好,一周后电极仍可用于检测.     

基于生物固定基质的电化学生物传感器研究

为了保持生物分子的生物活性并且能够给出检测所需的电化学输出信号,研究者发展了多种具有良好生物相容性的生物固定基质,包括水凝胶,有机-无机复合物衍生的溶胶-凝胶以及脂膜等,并将其引入电化学生物传感器。研究表明,这些生物基质的应用大大提高了电化学生物传感器的性能并拓宽了电化学生物传感器的应用范围。     

溶胶—凝胶法制备纳米SnO2材料

本文介绍了一种新型分散介质在溶胶－凝胶法制备纳米ＳｎＯ２材料中的应用。通过扫描电子显微镜比表面积测试仪和Ｘ射线衍射仪等实验等手段对ＳｎＯ２材料的粒径大小进行测试和分析，结果表明，本实验方法制备的ＳｎＯ２材料粒径最小为１５ｎｍ左右，实验还发现，热处理对ＳｎＯ２材料的粒径大小有很大的影响。     

溶胶-凝胶法制备纳米TiO2的凝胶机理研究

以硝酸为催化剂,钛酸丁酯为前驱物,用溶胶-凝胶法制备TiO2凝胶,研究了不同的掺水量、硝酸含量、反应温度、搅拌速度等反应条件下的凝胶过程,采用X射线衍射和透射电镜对纳米粒子的性能进行分析,找出制备纯度较高的锐钛矿型的纳米TiO2粉体的最佳工艺条件。     

一种葡萄糖氧化酶安培传感器研究

利用铁氰化钾作为电化学反应的媒介体,将葡萄糖氧化酶固定在羧甲基纤维素处理的碳电极表面,制成了一种新型的葡萄糖安培传感器.该传感器在恒电位0.4 V和葡萄糖氧化酶的催化作用下,使被检测物--葡萄糖--氧化,铁氰化钾还原,在电极表面产生灵敏氧化-还原峰,利用安培法可对葡萄糖进行间接测定.葡萄糖的测定范围为2.7～27 mmol/L,线性范围较好,拟合系数为0.997 8,灵敏度较当前葡萄糖传感器有明显的提高,11 s内即可达到输出稳态电流.同时该传感器对葡萄糖的测定避免了常规电化学传感器测定中样品所含大量的易氧化物质--如抗坏血酸和尿酸--带来的干扰.     

溶胶- 凝胶技术在光化学传感器中的应用

溶胶-凝胶技术是一种很有发展前途的材料制备方法，已在材料科学及有关的许多领域中得到了广泛的重视。文章综述了溶胶-凝胶技术的机理，以及传感器染料的包埋。     

壳聚糖／葡萄糖氧化酶复合膜结合静电自组装技术制备葡萄糖生物传感器的研究

该文利用壳聚糖(chitosan,CS)结合静电自组装方法固定葡萄糖氧化酶(glucose oxidase,GOx)制备了复合膜修饰的酶电极,构建了一种新型的葡萄糖生物传感器,实验结果表明随着(CS/GOx)薄膜层数增加,产生的氧化电流升高,可以通过增加组装次数提高酶电极中GOx的量.实验得到(CS/GOx)6、(CS/GOx)9和(CS/GOx)12响应时间分别为6.4 s、8.5 s和13.0 s,线性浓度范围为7×10-4～1.3×10-2mol/L、4.2×10-4～1.6×10-2mol/L、1.4×10-4～1.9×10-2mol/L.传感器的工作曲线表明增加GOx的层数可以提高传感器的灵敏度,但同时延长了响应时间.     

基于壳聚糖膜固定葡萄糖氧化酶生物传感器的研究

该传感器以电聚合于玻碳电极的甲苯胺蓝作为电子传递介体,用壳聚糖作为固酶基质,在真空状态下将葡萄糖氧化酶(GOD)固定于甲苯胺蓝修饰的玻碳电极表面。实验结果显示,用此法制备的传感器对葡萄糖的线性响应范围为0.0008～1.2g/L,并具有抗尿酸、抗坏血酸干扰的特点。     

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...     

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.     

Evaluation of amperometric glucose biosensors based on glucose oxidase encapsulated within enzymatically synthesized polyaniline and polypyrrole

In this article potential and suitability of enzymatically synthesized conducting polymers polyaniline (PANI) and polypyrrole (PPY) for fabrication of enzymatic amperometric glucose biosensors were evaluated. The polymerisation of these polymers was induced by catalytic activity of glucose oxidase (GOx) from Penicillium vitale cross-linked by glutaraldehyde (GA) on the graphite rod electrode (GOx-electrode) surface. The main precursors for initiation of polymerisation reactions were hydrogen peroxide as an initiator of polymerisation reaction and β-d-gluconic acid as a medium, which reduced the pH towards acidic one is the most suitable for the formation of PANI and PPY. During the polymerisation reactions the immobilized GOx was self-encapsulated within formed PANI or PPY layers in order to form GOx/PANI- and GOx/PPY-modified electrodes (GOx/PANI-electrode and GOx/PPY-electrode, respectively). Kinetic properties of GOx, which is acting as a biocatalyst in GOx/PANI- and GOx/PPY-electrodes, were studied and results were compared with GOx-electrode. The results show that in both GOx/PANI- and GOx/PPY-electrodes self-encapsulated GOx exhibited different parameters of catalysed reaction kinetics due to increasing diffusion limitations if compared with that of the GOx-electrode and it allowed the detection of glucose in a wider concentration interval. Moreover, both GOx/PANI- and GOx/PPY-electrodes exhibited good operational stability and reproducibility of analytical signal. The electrochemical characteristics of formed PANI and PPY in the GOx/PANI- and GOx/PPY-electrodes were also determined. In addition, the influence of temperature, pH and common interfering compounds on the steady-state current response of modified electrodes were investigated and discussed.     

A new glucose sensor based on encapsulated glucose oxidase within organically modified sol–gel glass

A non-mediated glucose biosensor is reported based on encapsulated glucose oxidase (GOD) within the composite sol–gel glass, which is prepared using optimum concentrations of 3-aminopropyltriethoxy silane, 2-(3, 4-epoxycyclohexyl)-ethyltrimethoxy silane, GOD dissolved in double distilled water and HCl. A white, smooth film of sol–gel glass with controlled thickness is also prepared at the surface of a Pt disk electrode without GOD to study the electrochemistry of ferrocene monocarboxylic acid at the surface of the modified electrode. The electrochemistry of ferrocene monocarboxylic acid at composite sol–gel glass electrode with varying thickness is reported. The GOD-immobilized film over the Pt disk surface shows a yellow colour. The new sol–gel glass in the absence and the presence of GOD is characterized by scanning electron microscopy (SEM). The enzyme-immobilized film of different thickness is made using varying concentrations of soluble sol–gel components applied to the well of the Pt disk electrode. The enzyme is cross-lined with the 3-aminopropyltriethoxysilane, one of the composite component of sol–gel glass using glyoxal at 4°C for 4 h. The response of non-mediated enzyme sensor is studied based on cyclic voltammetry and amperometric measurements. A typical amperometric response of the enzyme sensor having varying thickness of the modified sol–gel glass film is reported. The variation of the response time as a function of the film thickness is reported. The stability of cross-linked GOD to sol–gel glass is found to be more than a month without loss of enzymatic activity when the enzyme sensor is stored at 4°C.     

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.     

电化学极化玻碳电极构建的葡萄糖生物传感器

在硝酸溶液中电化学极化处理玻碳电极(GCE),以硫堇(TH)为电子介体,通过金-硫、金-氮共价键作用和静电吸附作用将纳米金(GNPs)、葡萄糖氧化酶(GOD)和辣根过氧化物酶(HRP)修饰于电极上,最后在电极上滴涂Nafion水溶液制备抗干扰膜并固定酶电极,构建了一种新型双酶葡萄糖生物传感器.实验结果表明:电化学极化处...     

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...     

Direct electrochemistry of glucose oxidase on screen-printed electrodes through one-step enzyme immobilization process with silica sol–gel/polyvinyl alcohol hybrid film

A one-step enzyme immobilization process with silica sol–gel/polyvinyl alcohol was described to achieve direct electrochemistry of glucose oxidase on screen-printed electrodes. The immobilized glucose oxidase displays a couple of stable and well-defined redox peaks with an electron transfer rate constant of 8.38 s⁻¹ and a formal potential of −460 mV (versus SCE) in phosphate buffer (0.05 M, pH 7.0) at a scan rate of 300 mV s⁻¹. The results suggested that conformation and bioactivity of glucose oxidase could be retained efficiently using the proposed immobilization method and the porous structure of screen-printed electrode surface was helpful for electron communication of glucose oxidase and the electrode. Furthermore, the modified electrode was used as a glucose biosensor, exhibiting a linear response to glucose concentration ranging from 0 to 4.13 mM and a sensitivity of 3.47 μA mM⁻¹ cm⁻² at an applied potential of −0.5 V. The detection limit of the biosensor is 9.8 μM, based on a signal-to-noise ratio of 3. The present work provided a promising strategy for fabricating a novel and disposable mediatorless glucose biosensor, which could be mass-produced through further development.     

Hybridization biosensor based on the covalent immobilization of probe DNA on chitosan-mutiwalled carbon nanotubes nanocomposite by using glutaraldehyde as an arm linker

A label-free DNA biosensor for hybridization detection of short DNA species related to the transgenic plants gene fragment of cauliflower mosaic virus (CaMV) 35S promoter was developed in this paper. The nanocomposite containing chitosan (CS) and mutiwalled carbon nanotubes (MWNTs) was first coated on a glassy carbon electrode. Then a highly reactive dialdehyde reagent of glutaraldehyde (GTD) was applied as an arm linker to covalently graft the 5′-amino modified probe DNA to the CS-MWNTs surface via the facile aldehyde-ammonia condensation reaction. The hybridization capacity of the developed biosensor was monitored with electrochemical impedance spectroscopy (EIS) using [Fe(CN)₆]^3−/4− as an indicating probe, and the experimental results showed that the biosensor had fast hybridization rate and low background interference. A wide dynamic detection range (1.0 × 10⁻¹³-5 × 10⁻¹⁰ M) and a low detection limit (8.5 × 10⁻¹⁴ M) were achieved for the complementary sequence. In addition, the hybridization specificity experiments showed that the sensing system can accurately discriminate complementary sequence from mismatch and noncomplementary sequences.