In the early nineties, Sidles (1991) came with a solution to combine the force microscopy techniques sensitive to atoms with that of magnetic resonance techniques: Magnetic Resonance Force... Show moreIn the early nineties, Sidles (1991) came with a solution to combine the force microscopy techniques sensitive to atoms with that of magnetic resonance techniques: Magnetic Resonance Force Microscopy (MRFM) was born. The technique was promising, big steps were taken, and the holy grail of atomic resolution imaging of biological tissues seemed within an arm’s reach. Unfortunately, the last steps are the most difficult. The technique is experimentally challenging and so far, the images of biological structures are no better than those obtained by other conventional techniques. In order to be an attractive technique, MRFM needs to be scientifically relevant while the technique is further improved towards the holy grail of imaging biological structures on the nanometer scale. In this thesis, we show how MRFM can usefully contribute to the field of condensed-matter. Show less
DNA-hosted silver clusters (Ag:DNAs) have attracted a lot of attention due to their small size (~20 atoms), wide range of applications in chemistry and biology, and sequence-dependent optical... Show moreDNA-hosted silver clusters (Ag:DNAs) have attracted a lot of attention due to their small size (~20 atoms), wide range of applications in chemistry and biology, and sequence-dependent optical tunability. Most of the previous studies are focused on the ensemble of emitters in solution. However, little is known about the optical properties of individual emitters, which is a crucial step towards understanding of their real nature, otherwise lost in ensemble averaging. We show that the excitation and emission spectra of individual emitters are broad even at 1.7 K (FWHM ~25 nm). Also, polarization measurements indicate that the excitation is not strongly dependent on the polarization of excitation light, whereas the emission is highly linearly polarized. Furthermore, from time-resolved measurements, we can conclude that the emission of single emitters can be fitted with single exponential decay curve, whereas the emitters organized with nanometer precision on the DNA scaffolds show double–exponential decay. This indicates the interaction between densely packed Ag:DNAs. Finally, we show that the DNA tubes can be used as a nano-contact glue between the colloidal particles functionalized with short DNA strands. Show less
