纳米碳管修饰铂结合溶胶-凝胶固定酶制备高性能胆碱生物传感器

Highly Sensitive Choline Biosensor Based on Nanotube Modified Pt Electrode Combined with Sol-Gel Immobilization

为了提高胆碱传感器的灵敏度和抗干扰性,以纳米碳管修饰铂电极为基础电极,采用溶胶-凝胶法固定胆碱氧化酶（ChOx）,构建了电流型胆碱检测生物传感器,对纳米碳管修饰电极的电化学特征进行分析,得知纳米碳管的引入不仅使电极对H2O2的催化电流增大,同时降低了电催化所需的恒定电位.讨论了缓冲液介质、pH值、酶负载量对传感器响应的影响.研究表明,所制备的传感器在pH 7.2、电位为0.15V条件下对氯化胆碱的线性响应范围为5.0×10^-6～1.0×10^-4 mol/L;检出限为5.0×10^-7 mol/L;灵敏度为9.48 μA/mmol/L.传感器的稳定性好,经过1个月,仍可保持初始电流的85%.抗干扰能力有很大提高.用于人体血清中的胆碱浓度测定,结果令人满意.

A novel amperometric choline biosensor have been fabricated with choline oxidase （ChOx） immobilized by the sol-gel method on the surface of the multi-wall carbon nanotubes modified platinum electrode in order to improve the sensitivity and the anti-interferential property. Throught andlysing the electrocatalytic activity of the modifial electrode by MWCNT, it is know that MWCNT could not only improve the current response to H2O2 but also decrease the electrocatalytic potential. The effects of experimental variables such as the phosphate buffer solutions, pH and the amount of loading enzyme were investigated for the optimum analytical performance by an amperometric method. This sensor shows sensitive determination of choline with a linear range from 5.0 × 10^-6 to 1.0 × 10^-4 mol/L when the operating pH and potential are 7.2 and 0. 15 V, respectively. The detection limit of choline was determined to be about 5.0 × 10^-7 mol/L. Selectivity for choline was 9.48μ.A · （retool/L）-1. The biosensor exhibits good stability, remainning 85% of its original current value after a month, and excellent anti-interferential. It has been applied to the determination of choline in human serum.