Cationic amphiphiles bearing imidazole fragment: From aggregation properties to potential in biotechnologies

Fabrication of multifunctioning systems using noncovalent self-assembly principles are of great importance in biomimetic drug and gene delivery systems construction. Herein, supramolecular systems based on homologous series of amphiphiles bearing imidazolium fragment (C(n)H(2n+1)Im(+) Br-, where n = 14, 16, 18) have been fabricated and studied. Their aggregation behavior, solubilization activity toward hydrophobic guest, interaction with DNA decamer as well as integration with lipid bilayer have been investigated. Elongation of hydrophobic fragment by two methylene groups results in 4-fold decrease of critical micelle concentration, however does not affect solubilization properties. Examination of capability of amphiphiles studied to interact with DNA decamer have revealed some unconventional features: size and charge characteristics of amphiphile/oligonucleotide complexes do not depend on the length of hydrophobic tail, but the latter affects the efficacy of component binding, which achieves 100% for all amphiphiles. Capability of amphiphiles studied to integrate with lipid bilayer strongly depends on the length of hydrophobic fragment: the lower homologue C(14)H(29)Im(+)Br(-) increases the permeability of lipid bilayer, while the higher homologues C(16)H(33)Im(+)Br(-) and C(18)H(37)Im(+)Br(-), vice versa, stabilize it. Enhance of capability of the drug (indometacin) to penetrate through lipid bilayer has been shown in the presence of C(14)H(29)Im(+)Br(-).