Highly Sensitive Nanomechanical Immunosensor Using Half Antibody Fragments

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• 作者：Shangquan Wu ; Hong Liu ; Xin M. Liang ; Xiaoping Wu ; Baomin Wang ; Qingchuan Zhang
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：May 6, 2014
• 年：2014
• 卷：86
• 期：9
• 页码：4271-4277
• 全文大小：362K
• 年卷期：v.86,no.9(May 6, 2014)
• ISSN：1520-6882

文摘

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.