INTERFACIAL INTERACTIONS OF Fe3+ WITH PAMAM DENDRIMER IN DIFFERENT PRESSURE CONDITIONS. MOLECULAR DYNAMICS

In the present paper, the interfacial interactions between carboxyl groups of a G2 PAMAM dendrimer and Fe3+ ions of Fe2O3 are studied using Molecular Dynamics simulation. As a novelty, these interactions have been simulated in two different conditions of pressure (20 atm and 80 atm, respectively). 7 ns simulation was done at neutral pH in explicit solvent (water) using an isothermal-isobaric (NPT) ensemble. In condition of high pressure the PAMAM dendrimer becomes more compacted and the branches negatively charged get closer to the dendrimer's core. At lower pressure, instead, the dimension of dendrimer increases. The radial distribution function of Fe3+ ions and the one of oxygens of PAMAM termination group have been calculated. The compaction of dendrimer at high pressure leads to less movement of chains. The structure at 20 atm is more open so that each ion can be bound to more than one charged residue.