Nanoscale Building Blocks Based on Chemically Modified DNA Helices

该提案位于纳米生物技术，化学和材料科学之间的界面，并专注于基于化学修饰DNA的纳米级构建模块和纳米机械设备的生成。这种化学修饰将有助于赋予DNA在材料科学和纳米生物技术中有用的功能特征，例如能够根据外部触发改变纳米级构建块的形状。该方案的目标结构是一个DNA纳米桶，桶壁要么由DNA环堆叠而成，要么由单个DNA双链线圈组成。DNA环的堆叠和单个DNA双链的螺旋将由大量紧密而可逆的金属亲和复合物结合在一起，这些金属亲和复合物的成分共价地附着在DNA的化学修饰碱基上。DNA纳米桶有两种用途。(1)纳米桶既可以作为纳米级的构建块，用于创建微尺度膨胀的横向组件。这些材料可以用作无机或金属纳米棒生长的模板，或者使用共价连接的刺激响应聚合物作为具有可控孔隙度的纳滤膜。（ii）由单个DNA链线圈组成的纳米桶也可以用作机械纳米级螺旋弹簧，其膨胀由金属亲和桥的受控打开触发，并由DNA纳米桶螺旋之间的静电排斥推动。这种类型的纳米机械装置可以用作纳米致动器来增加两个物体之间的距离，也可以用作生物传感器来检测重金属离子或毒素。

This proposal is located at the interface between nanobiotechnology, chemistry and materials science and focuses on the generation of nanoscale building blocks and nanomechanical devices based on chemically modified DNA. The chemical modifications will help endow DNA with functional characteristics useful in material science and nanobiotechnology such as the ability to change the shape of the nanoscale building blocks in response to an external trigger. The target structure of the proposal is a DNA nanobarrel in which the wall of the barrel is either composed of stacks of DNA-circles or of a coil of an individual DNA duplex. The stacks of DNA-circles and the whorls of the individual DNA duplex will be held together by a multitude of tight yet reversible metal affinity complexes whose constituents are covalently attached to the chemically modified bases of the DNA. Two applications are envisioned for the DNA nanobarrels. (i) Nanobarrels can either serve as nanoscopic building blocks for the creation of lateral assemblies of microscale expansion. These can be employed as templates for the growth of inorganic or metallic nanorods or as nanofiltration membranes with controllable porosity using covalently attached stimulus-responsive polymers. (ii) Nanobarrels composed of a coil of an individual DNA strand can also be used as mechanical nanoscopic coil springs whose expansion is triggered by the controlled opening of the metal affinity bridges and fuelled by electrostatic repulsion between the whorls of the DNA nanobarrels. This type of nanomechanical device might be used as a nanoactuator to increase the distance between two objects or as a biosensor to detect heavy metal ions or toxins.