Optical Dyes for Visualization of Structure and Function of Biomolecules and Biological Membranes

Licentiate thesis, 2011

To visualize the structure and function of biomolecules and biological membranes in the cell, optical dyes are important tools where in particular fluorescent probes provide a sensitive and selective detection. When cellular compartments are investigated it is crucial that the probe selectively binds to the area of interest and not exhibits unspecific binding affinity. In this thesis a series of three ruthenium complexes varying in lipophilicity are studied with the aim of investigating binding preferences towards biomolecules and lipid membranes as well as the cellular localization and the cellular uptake of the complexes. The complexes are studied both in vitro in solutions of DNA, RNA and lipid vesicles by spectroscopy and in vivo where their cellular staining patterns are compared with commercially available probes by employing confocal laser scanning microscopy. Three styryl dyes with the ability to probe electrostatic fields in membranes are also investigated with respect to their spectral properties in different solvents as well as their membrane interaction and orientation in two different model membrane systems. The dyes are shown to exhibit environment sensitive absorption and emission and they display different membrane binding properties. The results, for both categories of membrane and biomacromolecular probes, overall demonstrate that even relatively small changes in structure of probes may affect their binding affinity and other interaction characteristics.