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硅纳米线的无标记生物传感新方案，该硅纳米线用可切换的DNA分子进行功能化。纳米线传感器由于其在医学诊断和制药中的高度相关性而被广泛研究。其基本检测原理是依靠半导体场效应。作为拟议项目的主要新组成部分，这些电线将用DNA分子进行表面功能化，DNA分子的构象可以电转换。通过结合这种开关功能，我们打算证明，检测生化结合反应的灵敏度可以显着增强。我们的工作将集中在检测的DNA杂交作为模型系统首先。接下来，该方案可以扩展到其他系统，如抗体-蛋白质。该项目分为四个任务：1）用DNA层功能化硅表面。2)Si上DNA的受控电开关。3)将方法转移到硅纳米线。4)通过特异性降低屏蔽效应，显著增强器械灵敏度。应通过测量DNA结合动力学和亲和力，并通过确定检测特异性（低至单个碱基错配）来测试新方案。

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.