Two-photon excitation and confocal microscopy investigation of nanostructured polyelectrolyte shells

Two photon excitation (TPE) and confocal laser scanning microscopy (CLSM) allow obtaining structural and functional information at sub-micron resolution of three-dimensional specimens. We are interested in the relationship between the architectural motifs and functional properties of organized assemblies of nanostructured polyelectrolyte shells. Stepwise adsorption of oppositely charged polyelectrolytes onto micrometer sized organic and inorganic cores followed by core dissolution results in the formation of hollow polyelectrolyte shells, named nanocapsules. Nanocapsules can be used as protected environments for guest molecules allowing controlled release or entrance of substances. They are of both biological and medical interest since can be used for the controlled release and targeting of drugs as well as for the protection of enzymes and proteins. The structure and the permeability properties of the shells in hydrated state were investigated by a TPE architecture based on a compact CLSM, Nikon PCM2000, in which the ability to operate as a standard CLSM was preserved. Imaging was also probed by scanning force microscopy measurements on dried shells. We also plan to check other strategies for core removal and to perform confined experiments into the nanocaspules, including photopatterning and photobleaching ones.