DNA Directed Self-Assembly Of Metallic Plasmon Nanostructures And Their Properties Research

Compared with "top down" traditional approaches to pattern materials, "bottom-up" self-assembly can assemble and control the products at nanoscale easier, which express novel physical and chemical properties and promising applications of self-assembled products. Structural DNA nanotechnology is a burgeoning interdiscipline which has been widely employed for building complex nanostructures with nanoscale resolution and has received tremendous attention due to the sequence programmability and structural rigidity of DNA molecule. Particularly In this dissertation, a series of discrete nanostructures of gold nanoparticles(AuNPs) and gold nanorods (AuNRs) were rationally designed and successfully fabricated with DNA origami template. We tune the optical positions and intensities by precisely controlling the size and interparticle distance of AuNPs and the angles between the AuNRs. With the help of theoretical calculation, the correlation between the optical properties and the configurations of the nanostructures was clarified. The contents of this dissertation are described as follows:1. Preparation of functionalized building blocks of AuNPs and AuNRs:13 nm and 20 nm AuNPs were synthesized using trisodium citrate reduction method. AuNRs with sizes of 36 nm x 10 nm were synthesized using CTAB soft template method. These building blocks were functionalized with thiol DNA, which were stable in high salt concentration buffers and were further utilized for the self-assembly of discrete nanostructures.2. Self-assembly of discrete gold nanoparticles (AuNPs) tetrahedral nanoarchitectures:a series of discrete tetrahedral AuNR nanostructures were rationally designed and successfully assembled with a three-dimension DNA origami template. The morphology and yield of the structures were characterized by transmission electron microscope(TEM) and the optical properties of the assembled nanostructures were systematically studied by Circular Dichroism spectrometer and UV-vis-NIR spectrometer. The results showed that high purity product could be obtained by DNA self assembly. By adjusting the size and distance of the AuNPs, these discrete nanoarchitectures presented sensitive architecture-dependent optical responses. In addition, we also explored the association between plasmonic optical properties and configuration of the discrete AuNPs tetrahedral by theoretical calculation.3. Self-assembly of discrete gold nanorod(AuNR) dimmers:the gold nanorod(AuNR) dimmer architectures with different angles (0°,45°,90°,135°,180°, 225°,270°,315°,360°) were designed and self assembled using 2 D and 3 D DNA origami templates respectively. The morphology and yield of the structures were characterized by transmission electron microscope(TEM) and the absorption and chiral spectrum were also measured. The results showed that high purity production can be obtained by DNA self assembly. By adjusting the angle between the AuNRs, these discrete nanoarchitectures present sensitive angle-dependent optical responses. In addition, we also explore the association between angle alternation of the AuNR dimmers and plasmonic optical properties.