Unveiling the interaction between micelles of different surface-active ionic liquids and peptide drug HPV16E749-57

This work investigated the interaction between micelles of surface-active ionic liquids (SAILs) and the peptide drug HPV16E7 49-57 . Nine SAILs were designed, including 1-octyl-3-methyl imidazolium with glycinate ([C 8 mim][Gly]), lysinate ([C 8 mim][Lys]), aspartate ([C 8 mim][Asp]), leucinate ([C 8 mim][Leu]), or phenylalaninate [C 8 mim][Phe]; 1-ethyl-3-methyl imidazolium with oleate (C 2 mim][Ole]) or myristate ([C 2 mim][Myr]); and cholinium with oleate ([Cho][Ole]) or myristate ([Cho][Myr]). The CMC and micellar sizes of SAILs were compared for variation of SAIL constituents. UV–Vis spectroscopy, fluorescence spectroscopy, and solubility determination by HPLC found that the amino acid-based SAIL micelles had higher interaction abilities with the peptide drug than the fatty acid-based SAIL micelles. Their interaction abilities followed the order of [C 8 mim][Phe] > [C 8 mim][Asp] ≈ [C 8 mim][Leu] > [C 8 mim][Gly] > [C 8 mim][Lys] and [C 2 mim][Myr] > [Cho][Myr] ＞[C 2 mim][Ole] > [Cho][Ole], respectively. 1 H NMR analysis revealed that dissimilar solubilization patterns of the peptide in SAIL micelles and the varied interaction forces between SAIL hydrophilic heads and the peptide functional groups caused the different interaction abilities. [C 8 mim][Phe] micelles exhibited the strongest interaction ability due to the solubilization pattern between SAIL monomers and presence of phenyl group at the SAIL hydrophilic head. Furthermore, circular dichroism measurement showed conformational alteration of the peptide by the SAILs. This work lays a foundation for delivery of peptide drugs using SAILs.