Cheng Quan, Zhu Shimin, Song Jie, Zhang Na
Department of Chemistry, University of California, Riverside, CA 92521, USA.
Analyst. 2004 Apr;129(4):309-14. doi: 10.1039/b315656g. Epub 2004 Mar 15.
Redox functionalized microstructures of diacetylene lipids containing cell surface ligand GM1 have been prepared for the construction of an electrochemical biosensor for cholera toxin from Vibrio cholerae. Incorporation of lipid molecules with disulfide functionality into the microstructures allows for firm attachment of the microstructures on a gold surface to form a sensing interface. The observed morphology of the microstructures is platelet, with size around 240 nm as determined by dynamic light scattering and transmission electron microscopy. The electrochemical response stems from electron transfer between the electrode and the redox sites on the microstructures, and the Faradaic current is influenced by the binding events of protein toxins to the ligands displayed on the crystalline surface. Electrochemical characterization indicates that electron transfer of surface ferrocene on the gold electrode is facile. Differential pulse voltammetry was used to measure the current magnitude as a function of toxin concentration, and a working range expanding from 1.0 x 10(-8) to 5.0 x 10(-7) M was obtained. Bovine serum albumin (BSA) was used as a control agent with which no interference to Faradaic response was found in the same concentration range. Atomic force microscopy (AFM) was used to characterize the morphology and distribution of microstructures on the gold surface. The effectiveness of the design for bypassing surface fouling of proteins in electrochemical detection has been demonstrated, and a binding regulated electron hopping mechanism for the observed electrochemical behavior has been proposed.
已制备出含有细胞表面配体GM1的二乙炔脂质的氧化还原功能化微结构，用于构建检测霍乱弧菌霍乱毒素的电化学生物传感器。将具有二硫键功能的脂质分子掺入微结构中，可使微结构牢固地附着在金表面，形成传感界面。通过动态光散射和透射电子显微镜测定，观察到的微结构形态为血小板状，尺寸约为240nm。电化学响应源于电极与微结构上氧化还原位点之间的电子转移，法拉第电流受蛋白质毒素与晶体表面展示的配体结合事件的影响。电化学表征表明，金电极表面二茂铁的电子转移很容易。采用差分脉冲伏安法测量电流大小与毒素浓度的函数关系，得到了从1.0×10(-8)到5.0×10(-7)M的工作范围。牛血清白蛋白(BSA)用作对照剂，在相同浓度范围内未发现对法拉第响应有干扰。利用原子力显微镜(AFM)表征了金表面微结构的形态和分布。证明了该设计在电化学检测中绕过蛋白质表面污染的有效性，并提出了一种观察到的电化学行为的结合调节电子跳跃机制。
