Sajjadi Sharareh, Ghourchian Hedayatollah, Tavakoli Hassan
Laboratory of Microanalysis, Institute of Biochemistry and Biophysics, University of Tehran, Enghelab Street, Tehran, Iran.
Biosens Bioelectron. 2009 Apr 15;24(8):2509-14. doi: 10.1016/j.bios.2009.01.008. Epub 2009 Jan 14.
A simple mono-enzyme biosensor has been developed for specific determination of paraoxon (POX). In this biosensor, choline oxidase (ChOx) was introduced and used as a new recognition element. Besides, by application of Prussian blue (PB), as an electron mediator, the necessity of applying oxygen or hydrogen peroxide sensor, as the internal transducer, was abated. The method was based on PB chemically modified screen-printed electrode coupled with ChOx for detection of POX as inhibitor. The concentration of H(2)O(2) produced by ChOx was electrochemically determined by the PB modified electrode at -50 mV versus the internal screen-printed Ag pseudo-reference electrode. The decrease in current caused by the addition of inhibitor was used for evaluation of POX concentration. The experimental parameters such as the quantity of enzyme, substrate concentration and incubation time were optimized for ChOx inhibition. At the incubation time of 5 min, the biosensor response was linear from 0.1 to 1 microM of POX with a detection limit of 0.1 microM.
一种用于特异性测定对氧磷（POX）的简单单酶生物传感器已被开发出来。在这种生物传感器中，引入了胆碱氧化酶（ChOx）并将其用作新的识别元件。此外，通过应用普鲁士蓝（PB）作为电子媒介体，减少了使用氧气或过氧化氢传感器作为内部换能器的必要性。该方法基于PB化学修饰的丝网印刷电极与ChOx耦合，用于检测作为抑制剂的POX。ChOx产生的H₂O₂浓度通过PB修饰电极相对于内部丝网印刷Ag伪参比电极在-50 mV下进行电化学测定。由抑制剂添加引起的电流下降用于评估POX浓度。针对ChOx抑制作用，对酶量、底物浓度和孵育时间等实验参数进行了优化。在孵育时间为5分钟时，生物传感器对0.1至1 microM的POX响应呈线性，检测限为0.1 microM。
