<br/>Polymer-based micelles have raised considerable interest in applications as transdermal drug delivery material owing to their innate ability to form a structure with hydrophobic core encapsulating solvent-compatible particles and hydrophilic corona imparting water-solubility upon aggregation. We have studied the conformational changes of two novel amphiphilic homopolymers in water and toluene relevant to delivery applications using molecular dynamics simulations supplemented with enhanced sampling techniques. The individual homopolymer repeating units are amphiphilic with a hydrophobic dodecyl chain and a hydrophilic Poly(ethylene oxide) (PEO) chain attached via ether linkages to each repeating unit of the polymer backbone. We observe that these polymers exhibit highly dynamic conformations with the side arm orientations driven by the solvent polarity. In water these polymers exhibit a compact conformation with the hydrophobic arms retracted toward the backbone core, whereas in toluene the hydrophobic arms extended into the solvent. Different from the hydrophobic arms, the hydrophilic PEO chain orientations and backbone conformations are largely unperturbed by the solvent polarity. Probing the polymer microenvironment in different solvents to examine solute uptake supports the hypothesis that these polymers can selectively encapsulate/release guest molecules depending on the solvent polarity, highlighting the potential of these polymers as drug delivery vehicles.<br/><br/>Improving upon the polymer’s design and efficiency with the goal to increase the strength of segregation in the amphiphilic arms, we came up with several proposed schemes, one that terminated hydrophilic PEO arms with a charged amine group (NH3+) and substituting original PEO arms with Poly(vinyl) alcohol (PVA) arms. Preliminary structural analysis showed that these modifications increased the polymeric micelle’s size in both water and toluene. It also resulted in deeper and higher penetration of both solvent molecules. These modifications to the original polymer structure enhanced the incompatibility of amphiphilic blocks which achieved the design goal.

Design of tailored amphiphilic unimolecular polymeric micelles via molecular dynamics simulations

251st National Meeting (2016)

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