459347 Interaction of PCL Based Nanopolymeric Micelles with Model Lipid Bilayers Via Explicit and Implicit Solvent Coarse-Grained Simulations

Tuesday, November 15, 2016: 2:30 PM
Golden Gate 3 (Hilton San Francisco Union Square)
Abhinav S. Raman, Joshua Pajak and Y.C Chiew, Department of Chemical & Biochemical Engineering, Rutgers University, Piscataway, NJ

PCL based nanoparticles, typically formed from amphiphilic block copolymers consisting of water-soluble chains such as PEG, and functionalized with various ligands and other functional groups, are widely used in drug delivery applications. Nanopolymeric micelles formed from PEG-b-PCL copolymers have shown to evade the reticuloendothelial system, thereby providing improved circulation time to the nanocarriers, resulting in potential benefits to the betterment of human health. However, interaction of these nanocarriers with the cell membrane plays a crucial role in their endocytosis, potentially providing insights into their design and chemical make-up.

In this study, we perform coarse-grained molecular dynamics simulations to understand the interaction of micelles formed from MePEG-b-PCL copolymers, with a simple model DOPC lipid bilayer. Using existing models in the MARTINI coarse-grained force field for MePEG and PCL, we investigate the interaction of small micelles with a DOPC bilayer, in an explicit solvent setup. We found that the degree of hydrophobicity plays a crucial role in the interaction of the micelles with the bilayer, and also that the bilayer induced a change in morphology of the core-shell micelles to Janus particles during the internalization process. Key structural properties of the bilayer such as membrane thickness, lipid order parameter etc. were found to be largely unaffected during the internalization process, although dynamic and mechanical properties showed more changes when the bilayer was perturbed by the micelles. To explore larger spatio-temporal scales, the transferability of the developed models for MePEG and PCL to an implicit solvent setup using the ‘Dry MARTINI’ force field is also investigated. This paves the way for understanding the interactions of nanoparticles with large bilayers, at a much lower computational cost.

t = 0ns

t = 1000ns

Fig 1. Bilayer induced change in morphology of core-shell micelles to Janus particles (color codes: green-MePEG, red-PCL, blue- DOPC; only the head groups are shown for better clarity)

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See more of this Session: Inhomogeneous Polymers
See more of this Group/Topical: Materials Engineering and Sciences Division