(37g) Multiscale Molecular Modeling to Investigate the Aggregation of Polyamidoamine Dendrimers in Solution

The multi-valency of polyamidoamine (PAMAM) dendrimers makes them attractive candidates to encapsulate and deliver DNA and drugs in therapeutic delivery applications, and to effectively load and release organic pollutants for water and soil remediation. Experiments have shown that the aggregation of the dendrimers themselves can affect their effectiveness as a host for guest molecules. Because dendrimers are high molecular weight polymers, a coarse-grained (CG) molecular model is necessary to predict the aggregation properties of these molecules in solution. Generalized CG potentials of G5 PAMAM dendrimers solvated with explicit water and methanol molecules were calculated using the force matching method. The force-matching method has the advantage of being systematic because the CG pair forces are evaluated from the data gathered along trajectories from atomistic simulations and there is no need to run multiple simulations. Here we present our simulation results on the aggregation of PAMAM dendrimers as a function of solvent quality. We will also discuss simulation results for a system of PAMAM and phenanthrene in solution to demonstrate the competition between PAMAM-phenanthrene binding and PAMAM aggregation.