Self Assembly Of Gold Nanoparticles

The self-assembly of gold nanoparticles has become one of the most active area because of its high chemical stability, biocompatibility, etc. How to form ordered structures through self-assembly has attracted a lot of interest and is still a challenge. In this dissertation, we construct two types of gold nanoparticle self-assembly systems based on the base-pairing of the complementary single-stranded (ss) DNAs and the molecular recognition betweenβ-cyclodextrin and adamantane group or azobenzene group. It is found that the system formed through hydrogen bonding of ss-DNA turns out to be a well-organized structure and the system based on host-guest interaction also form a ordered structure to a certain degree.1. Self-assembly of different-size gold nanoparticles based on base pairing of ss-DNA AuNPs with a diameter of 5nm, 10nm, 20nm are first functionalized with types of noncomplementary ssDNA. These ssDNAs are composed of a 15 poly dT and a 15 base outer recognition part which are complementary to two recognition ends of the DNA linker. Through the base pairing of ss-DNA on gold nanoparticles and ss-DNA linker, systems consist of a combination of 5nm and 5nm, 10nm and 5nm, 20nm and 10nm, 20nm and 5nm gold nanoparticles are constructed. It is found that they all formed three-dimensional ordered structure of body-centered cubic (BCC) lattice, identified by SAXS, SEM, TEM experiments.2. Self-assembly of gold nanoparticles based on host-guest chemistryGold nanoparticles with a diameter of 10nm are first functionalized with mono-6-SH-β-CD. The two ends of PEG of three molecular weight (Mn = 600, 2100, 3000) are functionalized with adamantane group, while one end of PEG (Mn = 3000) is functionalized with adamantane group and the other is functionalized with azobenzene group. Through the host-guest interaction ofβ-cyclodextrin and adamantane, orβ-cyclodextrin and azobenzene, two types of gold nanoparticle systems are constructed. It is found that the formed structures are different due to the molecular weight differences of PEG. PEG with molecular weight of 2100 can form order structure to a certain degree.