Gold Nanoparticles Self-assembly Guided By DNA Origami

On account of the surface effect, volume effect, quantum size effect andmacroscopic quantum tunneling effect, nanomaterials have attracted great attentionin optics, electrics, chemistry and catalysis due to their wide fundamental interestsand potential applications in industry. In particular, gold nanoparticles have excellentoptical properties due to the surface plasmon resonance (SPR). The SPR peakposition of the gold nanoparticles can be adjusted by controlling the size,morphology and structure. With the special properties, these nanoparticles could beapplied in a wide range of fields. Theoretical studies have shown that self-assembledchain of gold nanoparticlescould generate field enhancement through plasmonicresonant coupling effect when they were arranged in designed pattern.. However,there is a limitation that the distance between the adjacent two nanoparticles must beclose to several nanometers which bring a great challenge to the self-assemblednanostructure of gold nanoparticle. Initially, Alivisatos and Mirkin used duplex DNAas the template to assemble gold nanoparticles. Other researchers, such as Bidault,also reported self-assembled gold nanoparticles chain with DNA. Nevertheless, thesize and boundary of the module are hard to control due to the limitation of the smallstructure of duplex DNA. As a result, the arrangment of chain structure and gapsbetween the self-assembled gold nanoparticles are hard to control. DNA origami,as nanoscale self-assembled templates, can provide engineered geometry andaddressability to solve this problem. This paper mainly discussed the methods forcontrolling the linear array and complex pattern of gold nanoparticles with the helpof DNA origami. DNA origami was designed with the different binding sites atspecific locations on the template to organize multiple gold nanoparticles covered byspecific sequences of thiolated DNA. Finally, the characterization of self-assemblednanostructure is discussed in detail.1. Gold nanoparticles of10nm diameter were synthesized. These nanoparticleshave uniform size distribution, and are modified with thiolated DNA. 2. Five gold nanoparticles were assembled on one side of Triangle-shaped DNAorigami template, forming a pattern of gold nanoparticles chain. The distancebetween adjacent two nanoparticles can be controlled down to2nm.3. Ten gold nanoparticles were assembled on two sides of Triangle-shaped DNAorigami template through the specific binding sites design. The angle of theself-assembled chain is manipulated to be about60o, and the distance betweenadjacent two nanoparticles is2nm.