Multi-level And Programmable Assembly Of Ordered Nanostructures By DNA Origami Technology

Since the beginning of structural DNA nanotechnology in the 1990 s,it has been in development for almost 30 years.DNA origami is a hot topic in structural DNA nanotechnology,which has attracted many researchers to explore in the past ten years.At present,it has been able to construct DNA nanostructures with diverse categories,shapes and topological characteristics with high yield.The nanostructure obtained by using DNA origami structures as the template can be used as an assembly element to induce the inorganic particles to perform multi-component nanoscale arrangement.However,due to the bottom-up assembly characteristics of DNA origami technology,the arrangements of resulting structure are usually disordered and borderless.It is significant to achieve orderly,precise,and controllable assembly of structures in nanoscale,which could be beneficial to the application fields such as biosensors and drug delivery.The contents of this thesis are to present the multi-level and precise controllable assembly by inducing nanoparticles onto DNA origami templates.The details are as follows:1.Using Magnetic Beads as Surfaces to Control Linear Assembly of DNA Origami to Introduce Array of Nanoparticles.Here we proposed a stepwise method for designated construction of 1D nanoparticles(NPs)array based on DNA origami self-assembly.In this method we used magnetic baeds(MBs)to program the entire assembly process,and only three DNA origamis building blocks were designed as structural elements to achieve the requirements of controllable and precise linear connection with high yield.2.High-throughput Assembly of Nanoclusters Guided by DNA Origami and Magnetic Bead.In recent years,researchers have found that the properties of such nanoclusters depend on not only the chemical identities of the individual NPs but also the 3D organization of the NPs.Here we proposed two different strategies to fabricate desired nanoclusters by introducing the surface of micro-sized MBs to 1)prepare patchy NPs with only part of the surface binding with the vertexes of DNA origami frames or 2)confine the assembly process on the surface of the MBs to avoid potential agglomeration.3.Using the Idea of Two-step Assembly to Realize Three-dimensional DNA Nanostructures with Controllable Number of Layers.In this thesis we proposed a strategy of two-step assembly in which DNA origami primitive was assembled in 1D firstly,and then the assembly product was used as the new assembly primitive to extend in another two dimensions,so as to realize the 3D DNA nanostructure assembly with controllable layers.The precise control for layers of product could be clearly observed by transmission electron microscope(TEM)and scanning electron microscope(SEM)respectively.