Lipophilic modification of peptides to form peptide amphiphiles allows for the controlled, responsive presentation of these bioactive molecules for applications in drug delivery, biomaterials, biosensing, and bioseparations. Given these applications, it is not surprising that nearly all studies of peptide-amphiphile assembly have been performed in aqueous solution. Use of nonpolar solvents may provide an avenue to the assembly of more complex structures, since nondirectional hydrophobic forces are replaced by orientation-specific dipolar interactions. Applications in emulsion-based pharmaceutical compounds may also be envisioned. In nonpolar solvents, small-molecule surfactants assemble into mostly spherical structures likely with the assistance of adventitious water. However, very small aggregates are also observed, depending on the specific headgroup chemistry.<br/> <br/>Here, we will present our results on the self-assembly properties of amino-acid-linked surfactants in nonpolar solvents. These materials have di-alkyl tails linked by amino acids with carboxyl or amine headgroups. We find that the solubility of these compounds in toluene or dodecane is very sensitive to the linker chemistry, and that nearly all compounds that do dissolve in these solvents display a well-defined critical micelle concentration. We will also discuss our preliminary results regarding the duplex assembly of peptide nucleic acids in nonpolar solvents, both with and without alkane modification, to assess the impact of solvent polarity on the specificity and stability of these structures. These materials have a substantial solubility in nonpolar solvents and are known to form very stable duplexes in aqueous solution.<br/>

Self-assembly of peptide amphiphiles in nonpolar solvents

253rd National Meeting (2017)

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