颗粒表面不对称DNA修饰及可控自组装研究

Asymmetrically modified and functionalized micro- and nanoparticles, because of their site distinctly different chemical and physical properties, have aroused widespread research interest. Some novel assemblies, such as novel crystal lattices and asymmetric colloidal chiral clusters can be fabricated through the interaction between asymmetrically modified particles. Terminally functionalized DNA can be used to modify the particles surface. DNA hybridization, thermoreversible and highly specific, has proved ideal for directing colloidal self-assembly on the micrometer and nanoscales by simply tuning the temperature. The self-assembly process of DNA modified particles is strongly dependent on the particles surface modification condition. This proposal is intended to establish a new particles surface asymmetric modification method using DNA, based on the photocleavage of 2-nitrobenzyl modified DNA and the toehold mediated DNA strand displacement reaction on particles surface. Furthermore, we intend to use this method to obtain DNA asymmetrically modified particles to study the self-assembly process and then fabricate some novel assembly structures.

表面不对称修饰的颗粒(微球及纳米粒子)由于其空间上一些特殊的物理化学性质引起了人们广泛的研究兴趣。利用不对称修饰颗粒间的相互作用可以构建一些新型的组装体，如新颖的晶体结构和手性团簇等。通过将DNA修饰到微球及纳米颗粒表面，利用DNA碱基间精准的、可预测的以及热可逆的氢键互补配对可用于调控和指导微球及纳米粒子的自组装过程。DNA修饰的微球及纳米粒子的自组装过程强烈地依赖于表面DNA修饰情况。本申请拟建立一种新型的微球及纳米金表面不对称DNA修饰方法。该方法基于2-硝基苄基修饰的DNA链紫外光切断的特性并结合颗粒表面toehold协助下的DNA链替换反应。进一步地利用该方法来获得多种表面不对称DNA修饰的微球及纳米金粒子。在此基础上，利用获得的不对称DNA修饰的颗粒间的相互作用来研究其组装行为并构建一些新型的组装体。

本项目通过生物素与链霉亲和素之间的特异性相互作用以及巯基与金表面的相互作用将光响应的DNA修饰到磁性微球以及纳米金表面。通过选择性光照来切断或者激活微球以及纳米金颗粒表面的DNA从而实现表面不对称DNA修饰并进一步地获得响应的组装结构。通过对项目研究内容进行扩展，将光响应的DNA接枝到镀金的玻璃表面，利用光刻掩模来选择性激活表面光响应的发卡DNA并引发后续的DNA杂交链增长反应实现了DNA聚合物刷表面图案化过程。此外我们还构建了DNA toehold协助下的DNA催化链替换反应网络并用于调控纳米金颗粒的组装行为。项目执行期间，发表相关SCI论文6篇。