Selective DNA dehybridization induced by laser irradiation on gold nanostructures

The objective of this thesis is to explore the feasibility of using light to control the surface reactions of DNA-Au nanoconjugates. Two types of gold nanostructures (Au nanoparticles vs. Au/SiO2 nanoshells) were modified with DNA oligonucleotides with different sequences. Due to the variation of their surface plasmon resonance peaks (520 nm for nanoparticles, 1100 nm for nanoshells), laser beams with corresponding wavelengths were used to irradiate the mix samples. It has been demonstrated that the laser-induced (photo-thermal effect) dehybridization of the dsDNAs on these nanostructures is selective, i.e., we can either release the single strands from the nanoparticles or from the nanoshells in the same solution independently. The experimental conditions have been optimized based on the selection of irradiation time and laser power. The selective, “remote” control of DNA reactions on the surface of nanostructures has potential applications in various clinical areas such as drug delivery and in vivo diagnostics.