Switchable DNA layers as novel scheme in silicon nanowire based bio-sensing

该项目的中心目标是实现一种基于可切换DNA分子功能化的硅纳米线的无标记生物传感的新方案。由于纳米线传感器在医疗诊断和制药方面的应用具有很高的相关性，因此受到了广泛的研究。其基本检测原理依赖于半导体场效应。作为拟议项目的主要新组成部分，这些电线将用DNA分子表面功能化，DNA分子的构象可以电子交换。通过结合这个开关函数，我们打算证明检测生化结合反应的灵敏度可以显著提高。我们的工作将首先集中在DNA杂交作为模型系统的检测上。随后，该方案可以扩展到其他系统，如抗体-蛋白质。该项目组织了四项任务：1)用DNA层对硅表面进行功能化。2)可控的DNA在硅上的电开关。3)将方法学移植到硅纳米线。4)通过具体降低屏蔽效应，大大提高了器件的灵敏度。新方案将通过测量DNA结合动力学和亲和力来测试，并通过确定检测特异性到单个碱基不匹配来进行测试。

The central objective of the project is to realize a novel scheme in label-free biosensing based on silicon nanowires that are functionalized with switchable DNA molecules. Nanowire sensors are intensively investigated owing to their high relevance for applications in medical diagnostics and pharmaceutics. The basic detection principle relies on the semiconductor field effect. As major new component of the proposed project these wires shall be surface-functionalized with DNA molecules whose conformation can be electrically switched. By combination with this switching function we intend to demonstrate that the sensitivity for detecting biochemical binding reactions can be significantly enhanced. Our work shall concentrate on the detection of DNA hybridization as model system first. Following, the scheme can be extended towards other systems such as antibody-protein. The project in organized in four tasks: 1) Functionalization of silicon surfaces with DNA layers. 2) Controlled electrical switching of DNA on Si. 3) Transfer of the methodology to silicon nanowires. 4) Substantial enhancement of the device sensitivity by specific reduction of screening effects. The new scheme shall be tested by measuring DNA binding kinetics and affinities, and by determining the detection specificity down to single base-mismatches.