CAS Key Laboratory of Mechanical Behavior and Design of Material, Department of Modern Mechanics, University of Science and Technology of China , Hefei, Anhui 230027, China.
Anal Chem. 2014 May 6;86(9):4271-7. doi: 10.1021/ac404065m. Epub 2014 Apr 22.
The improvement of sensitivity is of great significance to the application of biochemical sensor. In this study, we propose a micocantilever-based immunosensor in surface stress mode using half antibody fragments as receptor molecules. The thiol-containing half antibody fragment was obtained with a low loss of antibody biological activity and then was covalently and orientedly immobilized on the gold surface of microcantilevers via two native thiol groups. Such a one-step reaction and immobilization of receptor molecule simplify the preparation process of micocantilever immunosensor. Using shortened and highly oriented half antibody fragments as receptor molecules, the generation of surface stress and the transmission of stress from the interaction region of molecules to the surface of the microcantilever have been elevated significantly. The limit of detection (LOD) of the presented sensor has been significantly lowered to 1 pg/mL, or 1.1 pM in equivalence, which is a 500-fold improvement when compared with intact full antibody coated conventional micocantilever sensors. The results indicate that the half antibody fragment is well suited for the functionalization of the microcantilever surface and is generally applicable to all microcantilever immunosensor development, and this principle will help to design a functional film of devices with significantly lower LOD.
提高灵敏度对于生化传感器的应用具有重要意义。本研究提出了一种基于微悬臂梁的表面应力模式免疫传感器，该传感器使用半抗体片段作为受体分子。含硫半抗体片段的获得过程中抗体生物活性的损失较小，然后通过两个天然巯基基团将其共价且定向地固定在微悬臂梁的金表面上。这种一步反应和受体分子的固定简化了微悬臂梁免疫传感器的制备过程。使用缩短的和高度定向的半抗体片段作为受体分子，表面应力的产生以及分子相互作用区域到微悬臂梁表面的应力传递得到了显著提高。所提出的传感器的检测限（LOD）已显著降低至 1 pg/mL，或等价物中的 1.1 pM，与完整的全抗体涂覆的常规微悬臂梁传感器相比提高了 500 倍。结果表明，半抗体片段非常适合微悬臂梁表面的功能化，并且通常适用于所有微悬臂梁免疫传感器的开发，该原理将有助于设计具有显著更低检测限的器件功能薄膜。
