DNA nanostructures in advanced plasmonic applications

Martens, Kevin (2022): DNA nanostructures in advanced plasmonic applications. Dissertation, LMU München: Fakultät für Physik

Abstract

Chiral structures can be found anywhere from particle physics over electromagnetism to chemistry and biology. Although circular dichroism (CD) has long been used to trace changes of protein configurations or chiral molecular states, chiral plasmonic nanostructures have only shown their potential in recent years. The ability to design nanostructures with tailored geometries and specific functions on the nanoscale is one of the possibilities offered by DNA nanotechnology. In this thesis, we use DNA origami to assemble model meta-molecules from multiple plasmonic particles, accurately positioned in space. This approach allows us to build up varying molecular geometries piece by piece and study their impact on their surrounding optical near fields, confirming numerical simulations elucidating the intricate chiral optical fields in complex architectures. With this, we studied the emergence of CD signatures by step-wise constructing of a gold nanohelix, composed of single spherical nanoparticles. In this, we were able to show the effects of varying geometries by implementing sign flipping signals through addition or removal of single particles. We furthermore studied the effects of a spherical transmitter particle situated within a pair of nanorods in a chiral geometry. The transmitter particle not only enhances the CD response and causes a redshift of the plasmonic resonance frequency of the nanorods, it also triggers the emergence of an additional chiral signal at the resonance frequency of the nanosphere. In conclusion, we present an approach of utilizing specific plasmonic heating effects to construct a novel type of DNA nanowalker: a nanowheel. Unlike previous DNA walkers, which are based on the process of strand displacement, this nanowheel is fueled by light and could therefore potentially reach significantly higher speeds than any previous attempts.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 530 Physik
• Fakultäten: Fakultät für Physik
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 1. Juni 2022
• 1. Bericht­erstatter:in: Liedl, Tim