Schuvailo O N, Dzyadevych S V, El'skaya A V, Gautier-Sauvigné S, Csöregi E, Cespuglio R, Soldatkin A P
Laboratory of Biomolecular Electronics, Institute of Molecular Biology and Genetics of Ukrainian NAS, 150 Zabolotnogo Street, Kyiv 03143, Ukraine.
Biosens Bioelectron. 2005 Jul 15;21(1):87-94. doi: 10.1016/j.bios.2004.09.017.
This report describes technical improvements to the manufacture of a carbon fibre electrode for the stable and sensitive detection of H2O2 (detection limit at 0.5 microM). This electrode was also modified through the co-immobilisation of acetylcholinesterase (AChE) and/or choline oxidase (ChOx) in a bovine serum albumin (BSA) membrane for the development of a sensor for in vivo measurements of acetylcholine and choline. Amperometric measurements were performed using a conventional three-electrode system forming part of a flow-injection set-up at an applied potential of 800-1100 mV relative to an Ag/AgCl reference electrode. The optimised biosensor obtained was reproducible and stable, and exhibited a detection limit of 1 microM for both acetylcholine and choline. However, due to the high operating potential used, the biosensor was prone to substantial interference from other electroactive compounds, such as ascorbic acid. Therefore, in a further step, a mediated electron transfer approach was used that incorporated horseradish peroxidase into an osmium-based redox hydrogel layered onto the active surface of the electrode. Afterwards, a Nafion layer and a coating containing AChE and/or ChOx co-immobilised in a BSA membrane were successively deposited. This procedure further increased the selectivity of the biosensor, when operated in the same flow-injection system but at an applied potential of -50 mV relative to an Ag/AgCl reference electrode. The sensor exhibited good selectivity and a high sensitivity over a concentration range (0.3-100 microM) suitable for the measurement of choline and acetylcholine in vivo.
本报告描述了用于稳定、灵敏检测过氧化氢（检测限为0.5微摩尔）的碳纤维电极制造技术的改进。该电极还通过将乙酰胆碱酯酶（AChE）和/或胆碱氧化酶（ChOx）共固定在牛血清白蛋白（BSA）膜中进行了修饰，以开发用于体内测量乙酰胆碱和胆碱的传感器。使用常规三电极系统进行安培测量，该系统是流动注射装置的一部分，相对于Ag/AgCl参比电极的施加电位为800 - 1100 mV。所获得的优化生物传感器具有可重复性和稳定性，对乙酰胆碱和胆碱的检测限均为1微摩尔。然而，由于使用的操作电位较高，该生物传感器容易受到其他电活性化合物（如抗坏血酸）的严重干扰。因此，在进一步的步骤中，采用了介导电子转移方法，将辣根过氧化物酶掺入到沉积在电极活性表面的锇基氧化还原水凝胶中。之后，依次沉积一层Nafion层和一层含有共固定在BSA膜中的AChE和/或ChOx的涂层。当在相同的流动注射系统中操作，但相对于Ag/AgCl参比电极的施加电位为 - 50 mV时，该步骤进一步提高了生物传感器的选择性。该传感器在适合体内胆碱和乙酰胆碱测量的浓度范围（0.3 - 100微摩尔）内表现出良好的选择性和高灵敏度。
