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

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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.