An investigation of the self-assembly and physical properties of amphiphilic DNA crystals.

DNA是一种非凡的材料，用于构建纳米级精度的物体，因为核酸具有出色的分子识别能力，它们的合成简单易懂，以及多种可用的功能化选择。尽管核酸有许多有利的特性，但创建具有可控几何形状的DNA纳米级物体，进一步说，大型周期性DNA结构仍然是一个挑战。最近发现，通过将DNA纳米结构与疏水分子结合，可以克服这一挑战。它使我们能够获得称为C-Stars （DNA纳米星，由单螺旋组成的四个臂）的构建块，它能够自组装形成具有特定性质的晶体相。在我的博士学位期间，我将尝试研究这些两亲分子结晶的基本原理，以便更好地理解结晶过程是如何工作的。这些知识将使我能够完全控制所创建对象的结构，这将导致生产具有扩展范围的有用结构特性和功能的晶体相。我还将设计和开发一种选择尺寸的新系统，用于控制治疗剂的封装、释放和输送。此外，我将研究DNA网络中键重排的内部动力学，这对纳米结构晶体框架的力学性能有影响。最后，我将尝试利用DNA折纸的工具来创建更复杂的两亲性DNA构建块。最初，我的目标是设计纳米结构，其中臂由多个螺旋组成，称为束，而不是一个单一的螺旋。这将导致更硬的结构，从而允许生产具有更大晶格参数和孔隙率的晶体。最终，我将创造出具有与光波长相当的晶格参数的晶体，这将具有有用的光学特性。此外，使用多螺旋束可以更自由地在晶体中包含官能团，例如可以响应外部刺激以改变晶体结构的基序。

DNA is a remarkable material for building objects with nanoscale precision because of the excellent molecular recognition of nucleic acids, their straightforward and accessible synthesis as well as multiple available options of functionalization. Despite the numerous advantageous properties of nucleic acids, the creation of DNA nanoscale objects of controlled geometry and, further, large periodic DNA-based structures still remains a challenge. It was recently discovered, that it is possible to overcome this challenge by combining DNA nanostructures with hydrophobic molecules. It allows us to obtain building blocks called C-Stars (DNA nanostars with four arms composed of a single helix), which are able to self-assemble to form crystalline phases with defined properties.During my PhD I will try to investigate the principles underlying the crystallisation of these amphiphilic molecules in order to provide a better understanding of how the crystallization process works. This knowledge will allow me to fully control the structure of created objects, which will lead to production of crystal phases with an extended range of useful structural properties and functionalities. I will also be designing and developing a new system of chosen size for the controlled encapsulation, release anddelivery of therapeutic agents. Additionally, I will study the internal dynamics of bond rearrangements in the DNA networks, which have an implication on the mechanical properties of nanostructured crystalline frameworks. In the end, I will try to create more complex amphiphilic DNA building blocks by utilising the tools of DNA origami. Initially, I aim to design nanostructures in which the arms are composed of multiple helices, termed bundles, rather than a single helix. This will result in stiffer structure that will allow for the production of crystals with larger lattice parameter and porosity. Eventually I will create crystals that have a lattice parameter comparable with the wavelength of light, which will then have useful optical properties. Also, using multi-helix bundles will enable greater freedom in including functional groups in the crystal, such as motifs that can respond to external stimuli to change the structure of the crystals.