Tuning Nanostructured Lyotropic Liquid Crystalline Mesophases in Lipid Nanoparticles with Protic Ionic Liquids

• Published in: The journal of physical chemistry letters Vol. 12; no. 1; pp. 399 - 404
• Main Authors: Zhai, Jiali, Sarkar, Sampa, Tran, Nhiem, Pandiancherri, Shveta, Greaves, Tamar L, Drummond, Calum J
• Format: Journal Article
• Language: English
• Published: United States 14.01.2021
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.0c03318

We herein report 13 protic ionic liquids (PILs) as tunable solvation media to regulate the internal lyotropic liquid crystalline mesophase of monoolein-based nanoparticles. A range of nanostructures, including inverse bicontinuous cubic, inverse hexagonal, and sponge/lamellar mesophases, were produced and verified by synchrotron small-angle X-ray scattering. Notably, manipulating the cation/anion structures of the PILs can alter the monoolein packing behavior and cause a sequential phase transition (hexagonal → cubic → lamellar) in the nanoparticles. The solvent channels inside the nanoparticles were enlarged up to 40% under certain PIL-water conditions, making these materials prospective for encapsulation of large molecules. Finally, a freeze-drying study demonstrated the ability of PILs to preserve nanostructure upon reconstitution of the nanoparticles compared to that in pure water. This study opens a new route for fine-tuning lyotropic liquid crystalline structures using PILs, which circumvents issues encountered using conventional salts.