Improvement of Thermosensitive Liposome Stability by Cerasome Forming Lipid with Si-O-Si Network Structure

Background: Liposomes have been widely used in gene transfection and drug delivery systems due to their excellent biocompatibility and encapsulation ability, especially, the ability to deliver the gene/drug into the cells via the membrane fusion. Thermosensitive liposomes have been proven to be a precise and effective method for cancer treatment in many preclinical studies. But the imperfect crystalline arrangement between grains occurred, resulting in planar defects at the boundaries of membranes, compromising the stability of thermosensitive liposomes. Objective: In the present study, we developed a facile method to improve the stability of ordinary thermosensitive liposomes by introducing organic-inorganic hybrid materials with local Si-O-Si net. Method: A cerasome forming lipid, N, N-Dihxadecyl-N'- [(3-triethoxysilyl) propyl] urea, was synthesized and then introduced into the thermosensitive lipids to form the composite liposomes (named as cera-liposomes). The effects of the cerasome forming lipid on the cera-liposomes characteristics, including the morphology, drug loading, Zeta potential and stability of vesicles, were investigated. Results: Cera-liposomes were thermosensitive, and they had a loading efficiency over 2 folds more than conventional thermosensitive liposomes. With the enhanced sustain of Si-O-Si, cera-liposomes were able to avoid collapsing and fusing during storage, and had a good resistance to nonionic surfactant. More than 80% drug was still retained after storage of 15 days at room temperature. Conclusion: The cerasome forming lipid showed potential in improving the stability of thermosensitive liposomes. This novel kind of cera-liposomes could be a stable and effective drug carrier for anticancer applications.