Stoica Leonard, Ludwig Roland, Haltrich Dietmar, Gorton Lo
Department of Analytical Chemistry, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden.
Anal Chem. 2006 Jan 15;78(2):393-8. doi: 10.1021/ac050327o.
The present paper describes the principle and characteristics of a biosensor for lactose based on a third-generation design involving cellobiose dehydrogenase. As resulted from a previous comparative study (submitted manuscript), the novelty of this lactose biosensor is based on highly efficient direct electron transfer between two newly discovered cellobiose dehydrogenases (CDH), from the white rot fungi Trametes villosa and Phanerochaete sordida, and a solid spectrographic graphite electrode. CDH was immobilized on the electrode surface (0.073 cm2) by simple physical adsorption, and the CDH-modified electrode was next inserted into a wall-jet amperometric cell connected on-line to a flow injection setup (0.5 mL x min(-1)). The P. sordida CDH-based lactose biosensor, proved to be the better one, has a detection limit for lactose of 1 microM, a sensitivity of 1100 microA x mM(-1) x cm(-2), a response time of 4 s (the time required to obtain the maximum peak current), and a linear range from 1 to 100 microM lactose (correlation coefficient 0.998). The simplicity of construction and analytical characteristics make this CDH-based lactose biosensor an excellent alternative to previous lactose biosensors reported in the literature or commercially available. The CDH-lactose sensor was used to quantify the content of lactose in pasteurized milk, buttermilk, and low-lactose milk, using the standard addition method. No effects of the samples matrixes were observed. The operational stability of the sensor was tested for 11 h by continuous injection of 100 microM lactose (290 injections). The final signal of the sensor was maintained at 98% of its initial signal, with a low standard deviation of 1.72 (RSD 2.41%).
本文描述了一种基于第三代设计、涉及纤维二糖脱氢酶的乳糖生物传感器的原理和特性。根据之前的一项比较研究（已提交的手稿），这种乳糖生物传感器的新颖之处在于，来自白腐真菌绒毛栓菌和污色多孔菌的两种新发现的纤维二糖脱氢酶（CDH）与固体光谱石墨电极之间实现了高效的直接电子转移。通过简单的物理吸附将CDH固定在电极表面（0.073平方厘米），然后将CDH修饰的电极插入与流动注射装置（0.5毫升×分钟⁻¹）在线连接的壁喷式安培检测池中。事实证明，基于污色多孔菌CDH的乳糖生物传感器性能更佳，其乳糖检测限为1微摩尔，灵敏度为1100微安×毫摩尔⁻¹×厘米⁻²，响应时间为4秒（获得最大峰值电流所需的时间），乳糖线性范围为1至100微摩尔（相关系数0.998）。其结构简单且具有分析特性，使得这种基于CDH的乳糖生物传感器成为文献中报道的或市售的以往乳糖生物传感器的绝佳替代品。使用标准加入法，CDH - 乳糖传感器用于定量巴氏杀菌乳、酪乳和低乳糖乳中的乳糖含量。未观察到样品基质的影响。通过连续注入100微摩尔乳糖（290次注射）对传感器的操作稳定性进行了11小时的测试。传感器的最终信号保持在其初始信号的98%，标准偏差较低，为1.72（相对标准偏差2.41%）。
