| Colloidal particles are often considered to be programmable atomic analogues in the process of forming higher-order assemblies due to their similarities in the aspect of shapes and bonding abilities.Unlike highly directional interatomic interactions,the intrinsic properties of spherical colloidal particles make it difficult to precisely code the interactions between particles.In recent years,with the development of DNA nanotechnology,the interaction between colloidal particles can be redefined by introducing anisotropic patches on the surface of colloidal particles.Using the hydrogen-bond interaction between complementary base pairs of DNA patches,colloidal particles successfully constructed a series of nanoclusters and structural assemblies.However,how to develop a general and precise method to control the intergranular bonding modes,namely the functional patches installed directly in the location specified to the limited surface area of colloidal particles,thus generating colloidal particles self-assembled structures,and apply the method to the application of crystal defect and inorganic biomineralization,is still a serious challenge.To solve this problem,we propose a general method using DNA structure mediated colloidal particles to assemble ordered arrangements: By using the bonding modes similar to coordination between metal particles,colloidal particles surface can be accurately installed with functional patches mediated with the structure of DNA origami,so as to design and assemble varieties of delicate architectures.At the same time,we studied the application of self-assembled structures in crystal defect and inorganic biological mineralization.Using the specific recognition between DNA base-pairings,two single strands can form a stable double helix structure,which can insert the colloidal particles coated with DNA into the patchy DNA origami frames with different angles and numbers.Thus,the colloidal particles,which are originally in the free state and arranged in a complex manner,can be integrated into the ‘containers’--octahedral DNA Origami frames.Because of the programmability of DNA hybridization,octahedral framework theoretically defined the arrangement of functional patches in 3D manner,and then controlled the binding modes between colloidal particles.The Node-and-spacer approach,which is widely used in crystal engineering,can be applied to the construction of ordered structures.A series of ordered assemblies of colloidal particles,including dimer,linear chain,2D square planes and 3D cube etc.,are obtained by reasonably designing patchy colloidal particles with low symmetry and coding state.By means of transmission electron microscopy(TEM),small angle X-ray scattering(SAXS),cryogenic electron microscopy(Cryo-EM)and 3D reconstruction,the arrangement of different structures and the real state of samples were verified,and the reliability of this assembly strategy can be demonstrated.Crystal defect and inorganic biological mineralization are two popular application fields of structural DNA nanotechnology.In this thesis,based on chain displacement reaction,the constructed dimer and 2D plane structures are selected for the application research in the field of crystal defect,so as to introduce the crystal defect into the ordered structures of colloidal particles.In addition,we combine the inorganic biomineralization with ordered structures of colloidal particles,through the silica encapsulation process of the 2D planes and 3D scaffold chains,which significantly improves the structural hardness,and makes the soft DNA materials to get rid of the bondage of the liquid phase environment,to adapt to the solid-state characterization environment.The assembly approach proposed above has achieved good results in the accuracy of ordered assembly,and also can be used as a general mechanism to provide a variety of platforms for precise assembly of functional objects,and will have a wide application in nanometer-sized optical devices,crystal engineering and biological probe. |
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