The Interaction of Supramolecular Anticancer Drug Amphiphiles with Phospholipid Membranes.

The shape of drug delivery vehicles impacts both the circulation time and the effectiveness of the vehicle. Peptide-based drug amphiphiles (DAs) are promising new candidates as drug delivery vehicles that can self-assemble into shapes such as nanofilament and nanotube (diameter ~ 6-10 nm). The number of conjugated drugs affects the IC50 of these DAs, which is correlated to the effective cellular uptake. Characterizing and optimizing the interaction of these DAs and their assemblies with the cellular membrane is experimentally challenging. Long-time molecular dynamics can determine if the DA molecular structure affects the translocation across and interaction with the cellular membrane. Here, we report long-time atomistic simulation on Anton 2 (up to 25 μs) of these DAs with model cellular membranes. Results indicate that the interaction of these DAs with model cellular membranes is dependent on the number of conjugated drugs. We find that, with increased drug loading, the hydrophobic drug (camptothecin) builds up in the outer hydrophobic core of the membrane, pulling in positively charged peptide groups. Next, we computationally probe the interaction of differing shapes of these model drug delivery vehicles-nanofilament and nanotube-with the same model membranes, finding that the interaction of these nanostructures with the membrane is strongly repulsive. Results suggest that the hydrogen bond density between the nanostructure and the membrane may play a key role in modulating the interaction between the nanostructure and the membrane. Taken together, these results offer important insights for the rational design of peptide-based drug delivery vehicles.