Giulio Scocchi

MULTISCALE MODELING OF POLYMER/CLAY NANOCOMPOSITES

Multiscale molecular modeling (M3) is applied in many fields of material science, but it is particularly important in the polymer science, due to the wide range of phenomena occurring at different scales which influence the ultimate properties of the materials. In this context, M3 plays a crucial role in the design of new materials whose properties are infiuenced by the structure at nanoscale. In this work we present the application of a multiscale molecular modeling procedure to characterize polymer/clay nanocomposites obtained with full/partial dispersion of nanofillers in a polymer. This approach relies on a step-by step message-passing technique from atomistic to mesoscale to finite element level; thus, computer simulations at all scales are completely integrated and the calculated results are compared to available experimental evidences. In details, nine polymer nanocomposite systems have been studied by different molecular modeling methods, such as atomistic Molecular Mechanics and Molecular Dynamics, the mesoscale Dissipative Particles Dynamics and the macroscale Finite Element Method. The entire computational procedure has been applied to a number of diverse polymer nanocomposite systems based on montmorillonite as clay and different clay surface modifiers, and their mechanical, thermal and barrier properties have been predicted in agreement with the available experimental data.

Base Invaders. Coupling Experiments and Multiscale Modeling of Dendrimer-Based siRNA Delivery Agents

Injected, nano-scale drug delivery systems, or nanovectors, are ideal candidates to provide breakthrough solutions to the time-honored problem of optimizing therapeutic index for a treatment. Even modest amounts of progress towards this goal have historically engendered substantial benefits across multiple fields of medicine, with the translability, for example, from oncology to infectious diseases being granted by the fact that the progresses had a single common denominator in the underlying technological platform. In this work we combine multiscale molecular modeling and experimental approaches to define the mode and the molecular requirements of the interaction of oligonucleotide-based therapeutics (e.g., small interfering (si)RNA) and dendrimeric delivery reagents. In details, by mimicking in silico the experiments performed in vitro, information at the molecular level (e.g., interaction forces, mechanisms, structures, free energies of binding, self-assembly, etc.), which cannot be accessed by other experimental techniques, are obtained. Thus, critical molecular parameters for optimizing and de novo designing nanocargos for tissues and tumor specific uptake can be determined. This would provide valuable information to devise optimal delivery modalities that would increase the efficacy of siRNA therapeutics in cells and laboratory animals and move them toward clinical applications.