Applications of Peptide Nucleic Acid (PNA) in Nanotechnology

This dissertation is focused on the study of properties of PNA relevant for its use as a new material in nanotechnology applications. More specifically, it describes the synthesis and characterization of a molecular switch based on a ligand-modified PNA, the use of PNA for the sequence-specific functionalization of DNA origami, and the measurement of the rate constant for charge transfer through PNA in solution. Each of these three research projects covers an aspect of PNA relevant to nanotechnology. The molecular switch described in Chapter II is based on a modified PNA that contains two different metal binding sites, one based on 8-hydroxyquinoline and one based on 2,2’-bipyridine. UV titration showed that it is possible to use this PNA as a scaffold to organize copper ions in different oxidation states at different coordination sites and to translocate these ions between the two sites in response to redox reagents. PNA can be used also as a linker for the sequence-specific functionalization of DNA origami, as shown in Chapter III. AFM images showed that PNA strands modified with functional groups can be attached to the DNA origami at predefined positions by either annealing or invasion and that the efficiency of this functionalization is higher than that of the current strategies based on DNA. The photo-induced electron transfer properties of PNA in solution have been studied in Chapter IV. This research showed that the number of base pairs and the sequence of a PNA duplex used to connect an electron donor to an acceptor affect the electron transfer rate between these two groups. The research described in this thesis provides concepts and experimental results useful for the pursuit of PNA applications in nanotechnology.