Nanoscale Building Blocks Based on Chemically Modified DNA Helices

这项建议位于纳米生物技术、化学和材料科学的交界处，重点是基于化学修饰的DNA生成纳米级构建块和纳米机械设备。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，例如根据外部触发改变纳米级构建块的形状的能力。该提案的目标结构是DNA纳米管，其中桶的壁要么由成堆的DNA环组成，要么由单个DNA双链的线圈组成。DNA环的堆叠和单个DNA双链的螺纹将由大量紧密但可逆的金属亲和络合物结合在一起，这些络合物的成分共价连接到DNA的化学修饰碱基上。DNA纳米棒有两种应用前景。(I)纳米管材既可以作为纳米级的积木，也可以用于制造微尺度膨胀的横向组件。它们可以用作生长无机或金属纳米棒的模板，或使用共价连接的刺激响应型聚合物作为孔隙率可控的纳滤膜。(2)由单个DNA链的线圈组成的纳米管也可用作机械纳米线圈弹簧，其膨胀是由金属亲和桥的受控打开触发的，并由DNA纳米管螺纹之间的静电斥力推动。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，或者用作检测重金属离子或毒素的生物传感器。

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.