Construction Of Amphiphilic Nanostructures By DNA Origami Technology And Its Self-assembly

The self-assembly of biomolecules is a common phenomenon in nature,and it is also a hot topic in the field of biological nano-materials in recent years.The self-assembly of nanomaterials is closely related to their surface properties,which is obviously different from the complex hydrophilic and hydrophobic regions on the surface of natural biological nanostructures(such as protein assemblies,viruses,etc.).Therefore,the development of new technology to finely control the hydrophilic-hydrophobic distribution on the surface of nanomaterials,and then systematically study the effect of hydrophilic-hydrophobic distribution on the self-assembly behavior is of great significance which could be appied to regulate the assembly of nano-materials.DNA origami has developed rapidly in recent years.It can not only fabricate the defined structure according to the actual requirements,but also modify the structure accurately.Therefore,it is an ideal technology for the above research.DNA origami nanostructures are used as a platform to prepare a synthetic structure whose hydrophilic and hydrophobic substructures arranged in an orderly manner,to study its influence on the selfassembly behavior of nanostructures and to explore its biological effects.This research is not only of universal significance for understanding the self-assembly rules of hydrophobic interactions,but also provides support for in-depth study of the interaction between the surface substructure of nano-materials and organisms,and fine-tuning the biological effects of synthetic materials.The main contents of this study include:(1)Hydrophobic lipid molecules were accurately arranged on the surface of a twodimensional flexible DNA origami structure to systematically investigate the effects and rules of the number and distribution of hydrophobic lipid molecules on the self-assembly of twodimensional flexible DNA origami structures.After modifying hydrophobic molecules,twodimensional single-layer flexible DNA nanostructures formed cylindrical structures under hydrophobic interactions.As the number of hydrophobic molecule modifications increased,the proportion of curled structures also increased.In addition,when a small amount of hydrophobic molecules modified,the curling rate of DNA nanostructures with dispersedly modified hydrophobic molecules was higher than that with concentratedly modified hydrophobic molecules;(2)Rigid three-layer DNA origami structure was used to explore the effect of single-or double-sided modification of different numbers and distribution of hydrophobic lipid molecules on the self-assembly of three-dimensional DNA origami structures.Unlike flexible nanostructures,rigid nanostructures will forme a "sandwich" structure or an ordered stacked assembly structure;(3)Cylindrical structure was uesd to investigate the interaction between amphiphilic nanostructures and cell membranes.When the cylindrical structure enters the cell membrane,the structure will be reversed to form a new structure with hydrophobic molecules on the outside and hydrophilic nanostructures on the inside.(4)Atom Transfer Radical Polymerization was applied to DNA nanostructures,and the temperature-sensitive polymer polyisopropylacrylamide was grown in situ on the surface of two-dimensional DNA origami.Nano-scale hydrophilic and hydrophobic polymer patterns and simultaneously environmentally responsive nanostructures were prepared,and then the effect of temperature-sensitive hydrophobic polymers on the self-assembly of twodimensional DNA nanostructure was also discussed.