电流型微量胆固醇生物传感器的研制

将胆固醇氧化酶、胆固醇酯酶、过氧化物酶通过固定剂固定在碳糊印刷电极表面上，制成胆固醇传感器。这种传感器采用胆固醇氧化酶——过氧化物酶——电子传递剂体系检测全血中的总胆固醇含量，检测范围为l00-400mg／dL，检测所需血液样品量仅为2μL，是一种电流型微量生物传感器。传感器由于采用碳糊作为电极材料，添加海藻糖作为酶稳定刺，有效解决了酶等生物活性物质在电极上容易失活的问题，使传感器的存储时间可以延长到6个月以上，而酶的活性基本保持不变。     

介质电流型电极的作用机制探讨

生物传感器以其生物活性分子识别作为基础,有严格的专一性、较高的灵敏度,且操作方便简单,在生物过程控制和医疗临床上有广泛的应用前景,因此,新型生物传感器的开发研究日益受到重视。生物传感器由于其生物活性成分的不同(如酶、细胞、细胞器、免疫物质、受体等)和传感方式的不同(如压电型、电流型、电压型、FET 型、光敏型、热敏型等)分成许多类型,但现在研究得最多,应用范围最广的是电流型酶生物传感器。自从1962年 Clark和 Lyons 第一次提出“酶电极”概念以来,这种生物传感器发展迅速,已经从传统的第一代二次传感型电极,经过第二代一次传感型电极(1984,Cass et al),发展到第三代直接传感电极三代传感器的作用原理图见图1.     

基于蛋白质和纳米材料构建新型电化学生物传感器

随着蛋白质科学的飞速发展,越来越多研究者对基于蛋白质（酶）电子传递而研制新型电化学生物传感器给予了极大兴趣,同时,由于纳米材料的运用,各类新型电化学生物传感器不断报道。该文主要结合自己的工作,介绍几种采用蛋白质和纳米材料而研制的电化学生物传感器,以便与同行们进行交流。所使用的蛋白质主要包括：葡萄糖氧化酶、酪氨酸氧化酶、胆固醇氧化酶以及几种常见的血红素蛋白质如血红蛋白、     

农药残留检测生物传感器酶固定技术研究进展

酶生物传感器在农药残留检测方面具有传统检测方法不可比拟的优势,而酶的固定技术将直接影响酶生物传感器的性能.该文就酶的不同固定方法和使用的不同载体材料,对近二十年来农药残留检测生物传感器酶的固定技术的研究进展进行综述,并就不同固定方法,不同固定方法的特点和不同载体材料对生物传感器性能的影响作了简单介绍.     

电聚合二氧化锆固载辣根过氧化物酶的第三代生物传感器的研制

利用生物相容性良好的无机材料二氧化锆(ZrO2)对辣根过氧化物酶(HRP)进行直接固定,用交流阻抗法对修饰电极进行了表征,并用循环伏安法和计时电流法对过氧化氢(H2O2)生物传感器的性能进行了研究.结果表明,该法成功的制备了以电聚合ZrO2为载体的无介体第三代电流型生物传感器.其线性范围为1.00×10-6～1.87×10-3mol/L,线性回归方程为:ip(μA)=0.002 3 c(μmol/L)+2.9324,相关系数r为0.996 8,检测限为2.86×10-7 mol/L.     

碳纳米管修饰酶生物传感器的应用进展

很多酶生物传感器是利用氧化酶将底物氧化,同时产生过氧化氢,通过在电极表面检测过氧化氢的量来达到检测的目的。碳纳米管用于修饰电极,可降低化学物质氧化还原反应的过电位,改善生物分子氧化还原可逆性,达到提高检测的灵敏度和稳定性的目的。本文介绍了酶生物传感器及碳纳米管修饰酶生物传感器,并综述了近几年来碳纳米管修饰酶生物传感器的应用进展。     

碳纳米管在生物传感器中的应用

碳纳米管是一种新型的纳米材料,将其用于修饰电极,可以降低化学物质氧化还原反应的过电位,改善生物分子氧化还原可逆性,其大比表面积有利于酶的固定化,还能促进酶活性中心与电极表面的电子传递.碳纳米管的这些特性对于提高生物检测的灵敏度和稳定性具有重大意义,为生物传感器领域开辟了广阔的前景.     

生物传感器及展望

直接定量测定生物体液中的代谢物、氨基酸、蛋白质、激素、药物及其他生物物质,一直是分析化学家的艰巨任务之一.人们从不同途径进行种种努力以寻求简便、价廉、准确、实用的分析系统及方法.在这方面,卓有成效的是生物传感器.1960年L.C.Clark Jr,G.P.Hicks和S.J.Updike报道了第一只生物传感器——酶电极,开了生物传感器的先河.生物传感器使用具有特异选择性的生物元件,如酶、抗体、受体、微生物、组织、DNA及单克隆等,这些生物元件的特异选择性赋与了生物传感器的优异选择性.生物传感器的开发,为生物样品测定开辟了新的道路.     

用于农药残留快速检测的酶生物传感器研究进展

酶生物传感器以快速、操作简单、易于微型化等优势成为农药残留在线监测领域的研究热点。综述了近年来国内外农残速测酶生物传感器中所用酶的种类、酶固定化技术的发展与现状。探讨了影响酶生物传感器工业化进程的瓶颈,并展望了其发展趋势。     

磁性纳米粒子在生物传感器中的应用研究进展

磁性纳米粒子是一种新型的纳米材料,可应用于各种生物活性物质如蛋白质、DNA等的富集和分离、药物的磁靶向以及疾病的诊断和治疗等许多领域。由于磁性纳米粒子有着独特的化学和物理性能,已经成功的应用到磁控生物传感器、DNA传感器、蛋白质传感器、酶传感器以及其它类型的生物传感器中,并显著提高了生物传感器检测的灵敏度,缩短了生化反应的时间和提高检测的通量,为生物传感器领域开辟了广阔的前景。     

纳米颗粒增强尿酸酶生物传感器的研究设想

文章简要介绍了尿酸酶生物传感器研究的必要性及国内外研究现状;阐述了纳米颗粒增强酶生物传感器的初步机理,并对国内外纳米颗粒增强葡萄糖氧化酶生物传感器的研究进展进行评述.本课题组设想并正在进行有关纳米颗粒增强尿酸酶生物传感器方面的探索研究.     

检测神经性毒剂生物传感器的研究

阐述了通过微结构设计实现电化学技术与生物酶技术的有机结合,制造出对神经性毒剂敏感的生物传感器,分析了传感器的工艺制造过程,解决了酶的选择、酶的提纯、酶的固定化、底液、电极制作等关键技术。讨论了传感器的性能特点,稳定工作时间大于8h,传感器响应时间小于10min,零点漂移小于±2VDC。     

检测有机磷农药电流型胆碱酯酶传感器的研究进展

综述了检测有机磷农药电流型胆碱酯酶传感器的研究概况,对胆碱酯酶的固定化技术,工作电极的种类以及电化学修饰进行了探讨,并就其发展前景进行了展望。     

Enzyme-immobilized SH-SAW biosensor

A shear horizontal mode surface acoustic wave (SH-SAW) device has many attractions for chemical-sensing applications in liquid media. The SH-SAW that propagates on 36° rotated Y-cute, X-propagating LiTaO₃ is affected by a strong acoustoelectric interaction between the piezoelectric potential and electric properties of the adjacent liquid. This paper describes an enzyme-immobilized SH-SAW biosensor in which the detection principle is the acoustoelectric interaction due to the pH change in the enzyme reaction. Two kinds of enzymes, urease and cholinesterase, are immobilized on the sensor surface and highly sensitive detection of the enzyme reaction is obtained experimentally. The urease-immobilized SH-SAW biosensor is implemented in a liquid-flow system. By using the cholinesterase-immobilized SH-SAW sensor, we have succeeded in detecting an inhibition effect of a pesticide.     

Low temperature co-fired ceramic (LTCC)-based biosensor for continuous glucose monitoring

This article presents design, fabrication and testing of a miniature ceramic-based biosensor which is destined for continuous glucose monitoring. It is fabricated using well known LTCC (low temperature co-fired ceramics) technology. The biosensor consists of a microreaction chamber, three thick-film electrodes and a microdialysis tube. The detection process is based on oxidation of glucose by molecular oxygen in the presence of enzyme - glucose oxidase, GOx. One of the reaction products is a hydrogen peroxide which is detected amperometrically during its oxidation at a working electrode. Computational fluid dynamics (CFD) analysis was used for optimization of the biosensor geometry and considerations of the influence of operating conditions (flow rate) on mass transfer (diffusion) of the glucose within the microreaction chamber. Tests of the developed LTCC-based biosensor indicate its linear response to glucose concentration up to 9 mM with a relatively high sensitivity of about 147 nA/mM. Moreover, the properties of the presented ceramic biosensor are compared with properties of a similar device made in silicon/glass and in Perspex^®.     

Integrated biosensor employing a surface photovoltage technique

A monolithically integrated biosensor is constructed using a surface photovoltage (SPV) technique combined with a new patterning method for multiple enzyme integration. The SPV method provides a contactless sensing system leading to patterning flexibility. Photolithographical patterning methods using a water-soluble photocrosslinkable polymer (copolymer of dimethylacrylamide and cinnamoyloxyethylmethacrylate) are applied to immobilize the enzyme on a semiconductor surface. For bonding the enzyme membrane to the semiconductor surface, photoreactive poly-(meta azide styrene) is used, which bonds covalently with both the enzyme membrane and substrate. A pen-printing method has also been proposed for the patterning of enzyme films, which provides a simple method suitable for mass production.     

Surface-modified silicon nano-channel for urea sensing

Silicon nano-channels have been surface functionalized with the enzyme urease for biosensor applications to detect and quantify urea concentration. The device is nanofabricated from a silicon-on-insulator (SOI) wafer with a top down lithography approach. The differential conductance of silicon nano-channels can be tuned for optimum performance using the source drain bias voltage, and is sensitive to urea at low concentration. The experimental results show a linear relationship between surface potential change and urea concentration in the range of 0.1–0.68 mM. The sensitivity of our devices shows high reproducibility with time and different measurement conditions. The nano-channel urea biosensor offers the possibility of high quality, reusable enzyme sensor array integration with silicon-based circuits.     

Nanobiosensors: optofluidic, electrical and mechanical approaches to biomolecular detection at the nanoscale

Next generation biosensor platforms will require significant improvements in sensitivity, specificity and parallelity in order to meet the future needs of a variety of fields ranging from in vitro medical diagnostics, pharmaceutical discovery and pathogen detection. Nanobiosensors, which exploit some fundamental nanoscopic effect in order to detect a specific biomolecular interaction, have now been developed to a point where it is possible to determine in what cases their inherent advantages over traditional techniques (such as nucleic acid microarrays) more than offset the added complexity and cost involved constructing and assembling the devices. In this paper we will review the state of the art in nanoscale biosensor technologies, focusing primarily on optofluidic type devices but also covering those which exploit fundamental mechanical and electrical transduction mechanisms. A detailed overview of next generation requirements is presented yielding a series of metrics (namely limit of detection, multiplexibility, measurement limitations, and ease of fabrication/assembly) against which the various technologies are evaluated. Concluding remarks regarding the likely technological impact of some of the promising technologies are also provided.     

Application of functionalised carbon nanotubes immobilised into chitosan films in amperometric enzyme biosensors

A new approach for building a bio-conductive interface for enzyme immobilisation is described. This strategy permits very simple preparation of the enzyme biosensor and also reveals direct electron transfer features. A graphite-epoxy resin composite (GrEC) electrode modified with functionalised multi-wall carbon nanotubes (MWCNTs) immobilised by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide together with N-hydroxysuccinimide (EDC–NHS) in a chitosan (Chit) matrix was prepared and characterised by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of hexaammineruthenium (III) chloride. It was then used as a base for glucose oxidase (GOx) immobilisation by the simple method of crosslinking with glutaraldehyde (GA) with bovine serum albumin (BSA) as carrier protein. The resulting mediator-free biosensor was applied to the determination of glucose in amperometric mode at different applied potentials and the mechanism of reaction was also investigated by cyclic voltammetry, with and without dissolved oxygen in solution. Analytical parameters, as well as reproducibility, repeatability and stability were determined. Interferences were assessed using different compounds usually present in natural samples, such as wines, juices or blood, in order to evaluate the selectivity of the developed biosensor. The novel combination of carbon nanotubes immobilised with chitosan crosslinked with EDC–NHS and glucose oxidase immobilised by crosslinking with glutaraldehyde offers an excellent, easy to make biosensor for glucose determination without interferences.