| With the development of chemical biology,the nucleic acid is not only a carrier of genetic information in the traditional sense but a biomaterial for constructing new microscopic and macroscopic materials as well.As a novel type of nanostructures synthesized and self-assembled by nucleic acids,framework nucleic acids(FNAs)are designed and modified in nanometer precision,which have been widely used in the fields of chemistry,materials science,and biomedicine.Taking advantage of nano-level addressability,spatial framework characteristics,and excellent programmability,FNAs are controlled arrangement.The arrangements are mainly including two types: one is the controllable arrangement of the FNAs itself,that is,FNAs as monomers to construct higher order structures;the other one is the controllable arrangement of other materials on FNAs,that is,other materials(including small molecules,macromolecules or nanoparticles with nanometer precision)are arranged on the FNAs template.These two types of arrangements could have great significance for the synthesis of nanomaterials with better properties.This study focused on the controllable arrangement of FNAs,and explored the following two aspects: 1.Design and construct 3D higher order dendrimer structures with DNA tetrahedron as a monomer.With excellent three-dimensional structure,DNA tetrahedron has outstanding physicochemical properties: 1)DNA tetrahedron is simple in structure and easy to synthesize,that is,four single strands DNA can be assembled by one-step annealing;2)based on the excellent stability and self-assembly ability of DNA tetrahedron,it can be designed that the arm chains extending from the DNA tetrahedron,and DNA tetrahedrons can be connectioned by the complementary pairing of the arm chains.Therefore,by precisely designing the arm chains and assembly units of the tetrahedral monomers,controlling the assembly conditions and the assembly process,the controllable arrangement of the tetrahedral monomers can be realized.We designed trivalent and tetravalent DNA tetrahedral structures with 3 and 4 arm chains on monomers,and a DNA tetrahedron with one arm chain as a “terminator”.According to layer-by-layer assembly process and fractal assembly process,the 3D higher order dendrimer structures of three branches and four branches were successfully constructed.Subsequently,all the higher order structures were verified by various characterization techniques.This research expanded the types and structures of FNAs,and provided a new way to further construct structural materials with new properties.2.Controllable arrangement of nanoparticles on DNA origami templates by selective metallization,this method is versatile.The physicochemical properties of nanoparticles are closely related to their size and shape.Controlling the size and shape of nanoparticles and arranging them into ideal nanostructures are the key to achieving the ideal properties of nanomaterials.DNA origami structures are sequence-specific and spatially addressable,allowing nanoparticles to be accurately positioned on DNA origami.Therefore,DNA origami provides an excellent template for building nanomaterials with novel structures and functions.We designed a specific pattern of DNA origami template by simply extending the staples at a definite position on the DNA origami.After added corresponding reaction substrates to the DNA origami template,selective metallization reaction in situ of DNA origami was performed.The precise arrangement of metals on DNA origami is realized,and the pattern we designed was built up.This method is versatile: for template pattern,different patterns can be designed by selecting other DNA origami templates or changing the position and the number of extending staples;for material types,it can be applied to a variety of materials.We have realized Controllable arrangement of various metals,metallic compound and metal alloys on DNA origami templates.This research is expected to achieve the integration of nanowires,providing the possibility to build new nanodevices. |
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