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Understanding the early onset of neurodegeneration is crucial to deploy specific treatments for patients before the process becomes irreversible. Copper has been proposed as a biomarker for many neurodegenerative disorders, being the ion released by pathologically unfolded proteins involved in many biochemical pathways. Dendrimers are macromolecules that bind metal ions with a large ion/ligand ratio, thus, allowing a massive collection of copper. This work provides structural information, obtained via molecular modeling and EPR, for the binding sites of copper in polypropyleneimine (PPI) dendrimers, especially in the maltose decorated form that has potential applications in diagnosis and therapies for various types of neurodegenerations. The analysis of the EPR spectra showed that, at the lowest Cu concentrations, the results are well supported by the calculations. Moreover, EPR analysis at increasing Cu(II) concentration allowed us to follow the saturation behavior of the interacting sites identified by the modeling study.

The internal flexibility and interacting ability of PAMAM-dendrimers having 4-carbomethoxypyrrolidone-groups as surface groups (termed Gn-Pyr), which may be useful for biomedical purposes, and ion traps were investigated by analyzing the EPR spectra of their copper(II) complexes. Increasing amounts (with respect to the Pyr groups) of copper(II) gave rise to different signals constituting the EPR spectra at room and low temperature corresponding to different coordinations of Cu(2+) inside and outside the dendrimers. At low Cu(2+) concentrations, CuN4 coordination involving the DAB core is preferential for G3- and G5-Pyr, while G4-Pyr shows a CuN3O coordination. CuN2O2 coordination into the external dendrimer layer was also contributing to G3- and G4-Pyr spectra. The structures of the proposed copper-dendrimer complexes were also shown. G4-Pyr displays unusual binding ability toward Cu(II) ions. Mainly the remarkably low toxicity shown by G4-Pyr and its peculiar binding ability leads to a potential use in biomedical fields.

Lecithin/dodecylamine/lactose mixtures in ethanol/aqueous media led to the formation of sponge mesoporous silica (SMS) materials by means of tetraethoxysilane (TEOS) as silica source. SMS materials show a "sponge-mesoporous" porosity with a pore diameter of about 5-6 nm, in accordance to the length of a lecithin bilayer. SMS synthesis was developed to create a new class of powerful biocatalysts able to efficiently encapsulate enzymes by adding a porosity control to the classical sol-gel synthesis and by using phospholipids and lactose as protecting agents for the enzymes. In the present study, the formation of SMS was investigated by using electron paramagnetic resonance (EPR) probes inserted inside phospholipid bilayers. The influence of progressive addition of each component (ethanol, dodecylamine, lactose, TEOS) on phospholipid bilayers was first examined; then, the time evolution of EPR spectra during SMS synthesis was studied. Parameters informative of mobility, structure, order, and polarity around the probes were extracted by computer analysis of the EPR line shape. The results were discussed on the basis of solids characterization by X-ray diffraction, nitrogen isotherm, transmission electron microscopy, and scanning electron microscopy. The results, together with the well-known ability of ethanol to promote membrane hemifusion, suggested that the templating structure is a bicontinuous phospholipid bilayer phase, shaped as a gyroid, resulting of multiple membrane hemifusions induced by the high alcohol content used in SMS synthesis. SMS synthesis was compared to hexagonal mesoporous silica (HMS) synthesis accomplished by adding TEOS to a dodecylamine/EtOH/water mixture. EPR evidenced the difference between HMS and SMS synthesis; the latter uses an already organized but slowly growing mesophase of phospholipids, never observed before, whereas the former shows a progressive elongation of micelles into wormlike structures. SMS-type materials represent a new class of biocompatible materials and open a bright perspective for biomolecule processing for pharmaceutical, biocatalysis, biosensors, or biofuel cell applications.