Incorporating a Tetrapeptide into Lyotropic Direct Hexagonal Mesophase

An approach to incorporate a bioactive hydrophobic substance, C₂₂H₃₂N₄O₇ tetrapeptide (TP), into the structure of the hexagonal mesophases C₁₂EO₁₀/H₂O and C₁₂EO₁₀/La(III)/H₂O was proposed. Concentration and temperature ranges of mesophases in the C₁₂EO₁₀/H₂O/TP and C₁₂EO₁₀/La(III)/H₂O/TP systems were established. The analysis of the X-ray diffraction data revealed a change in the structural characteristics of mesophases in the presence of tetrapeptide. Formation of a denser packing of molecules in the mesophases with TP was detected. Based on the FTIR spectroscopy data, intermolecular changes in the systems were examined. Pulsed-gradient spin-echo NMR self-diffusion experiments were performed to characterize the structure of lyomesophases depending on system composition and temperature. The degree of hydration of water molecules in lyomesophases was analyzed. The data confirmed successful incorporation of tetrapeptide into the structure of lyomesophase and, therefore, the possibility of using hexagonal mesophases for both incapsulation and delivery of biomolecules.