Manso Javier, Mena M A Luz, Yáñez-Sedeño P, Pingarrón José M
Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
Anal Biochem. 2008 Apr 15;375(2):345-53. doi: 10.1016/j.ab.2007.12.020. Epub 2007 Dec 23.
A biosensor design involving coimmobilization of fructose dehydrogenase (FDH) and inulinase (INU) on a gold nanoparticle-cysteamine (Cyst) self-assembled monolayer (SAM)-modified gold electrode (Au(coll)-Cyst-AuE), for the determination of the carbohydrate inulin in foodstuffs, is reported. Tetrathiafulvalene (TTF), used as the mediator, was also coimmobilized by crosslinking with glutaraldehyde. INU catalyzes the hydrolysis of inulin, forming fructose that is detected through the fructose dehydrogenase system by the electrochemical oxidation of TTF at the bioelectrode. The variables involved in the preparation and performance of both the single enzyme FDH biosensor and the bienzyme inulin biosensor were optimized. The FDH-Au(coll)-Cyst-AuE biosensor exhibited rapid and sensitive response to fructose, allowing the obtention of improved analytical characteristics for the determination of fructose with respect to other FDH electrochemical biosensors. Moreover, the lifetime of this biosensor was 35 days. The bienzyme INU/FDH-Au(coll)-Cyst-AuE biosensor provided a calibration plot for inulin in the (5-100)x10(-6) M linear range, with a detection limit of 6.6 x 10(-7) mol L(-1). One single bienzyme biosensor responded within the control limits, set at +/-3x the standard deviation of the currents measured on the first day of use, for more than 5 months. Furthermore, the biosensor exhibited high selectivity with respect to other carbohydrates. The usefulness of the biosensor was evaluated by the rapid determination of inulin in food products involving minimization of the fructose interference.
报道了一种生物传感器设计，该设计将果糖脱氢酶（FDH）和菊粉酶（INU）共固定在金纳米颗粒-半胱胺（Cyst）自组装单层（SAM）修饰的金电极（Au(coll)-Cyst-AuE）上，用于测定食品中的碳水化合物菊粉。用作媒介体的四硫富瓦烯（TTF）也通过与戊二醛交联进行共固定。INU催化菊粉水解，生成果糖，果糖通过生物电极上TTF的电化学氧化，经果糖脱氢酶系统进行检测。对单酶FDH生物传感器和双酶菊粉生物传感器的制备及性能相关变量进行了优化。FDH-Au(coll)-Cyst-AuE生物传感器对果糖表现出快速且灵敏的响应，相较于其他FDH电化学生物传感器，在果糖测定方面具有更好的分析特性。此外，该生物传感器的寿命为35天。双酶INU/FDH-Au(coll)-Cyst-AuE生物传感器在(5 - 100)×10⁻⁶ M线性范围内提供了菊粉校准曲线，检测限为6.6×10⁻⁷ mol L⁻¹。单个双酶生物传感器在设定为使用第一天测量电流标准偏差±3倍的控制限内响应，持续超过5个月。此外，该生物传感器对其他碳水化合物具有高选择性。通过快速测定食品中的菊粉并将果糖干扰降至最低，评估了该生物传感器的实用性。
