DNA-assisted Purification Of Gold Nanotriangles And Researches Of Related Properties

Noble metal nanoparticles with specific characteristics of the surface plasmon resonance(SPR),especially those with anisotropic shapes,can greatly enhance the electromagnetic field near the tips of particles,and thus resulting in a significant signal enhancement,which can significantly reduce the detection limit,thus have broad application prospects in biochemical detection and other fields.DNA is a natural nanomaterial,with its sequence-specific recognition feature,it can not only be selfassembled into micro-/nano-structures such as DNA origami,but also can regulate and construct advanced structures of other nanomaterials by designing DNA sequences.At present,DNA nanotechnology has gradually developed into a mature and effective nano-manipulation technology.The main research content of this dissertation is DNA-assisted separation of polydispersed gold nanoparticles to realize the efficient separation and protection of the gold nanoparticles of different morphology,and precise assembly of gold nanoparticles realized by using the programmable DNA.The details are as follows:1.Effective separation of the gold nanoparticles of different shapes and sizes was achieved by DNA-assisted electrophoretic separation,and monodispersed anisotropic nanoparticles were successfully obtained.This method is universal applicable and is expected to be a common method for noble metal nanoparticles separation.2.By centrifuge-accelerated depletion effect,triangular gold nanoparticles of different sizes were quickly purified while maintaining sharp tips.This method is easy and efficient to realize the separation of triangular gold nanoparticles,and is expected to be extended to the separation of other nanoparticles of different components with non-spheres and low symmetry morphologies.3.The process of etching of triangular gold nanoparticles in solution and the oscillating deformation phenomenon during the etching process were studied,and the mechanism was discussed.Studies have shown that HS-DNA has certain hindrance effect on the etching of triangular gold nanoparticles in solution.The morphology of triangular gold nanoparticles functionalized was effectively protected by HS-DNA.Meanwhile,triangular gold nanoparticles were encoded through DNAfunctionalization.4.The precise control of the assembly direction of triangular gold nanoparticles on DNA origami was realized by modifying the sequence of DNA strand at specific locations in DNA origami structure,which provided a basis for further improving the structure precision of gold nanoparticles assembled by DNA origami.In conclusion,this dissertation is a basic research on the combination of DNA nanotechnology and noble metal nanomaterials,and is of great significance for guiding the research of DNA nano-manipulation.