Characterization of Dendrimers and Their Interactions with Biomolecules for Medical use by Means of Electron Magnetic Resonance

The studies presented in this report arise from collaborations in the framework of the COST action TD0802. We used both the spin label and the spin probe techniques in order to characterize the dendrimers and their interactions with biomolecules by means of a computer aided analysis of the electron paramagnetic resonance (EPR) spectra. First, we characterized different dendrimers by analysing the complexes formed with Cu²⁺ in water solutions in different experimental conditions. The oligosaccharide shell of glycodendrimers affects both the internal and external metal ion complexation providing axial and rhombic geometries. Anionic carbosilane dendrimers are able to selectively coordinate copper ions at the dendrimer internal/external surface, depending on generation and functionalization with sulfate or carboxylate groups. Amine‐functionalized dendrons with cholesterol groups at the focal point were also characterized for their structure and interacting ability, but we also analysed the aggregates formed by the self‐assembling dendrons using spin probes able to insert into the hydrophobic domain. Surfactant spin probes were also used to study the encapsulation of dendrimers into lamellar, cubic and hexagonal lyotropic liquid crystals (LLCs) as drug delivery systems. Finally, we used EPR probes to monitor the formation of amyloid and prion fibrils, responsible of neurodegenerative diseases, and the role of different dendrimers to prevent the fibril formation. The aggregation behavior over time was analyzed in the absence and presence of phosphorous dendrimers and glycodendrimers thus providing precious information on the kinetics of aggregation and the type of interactions occurring in the system