Emerging advances in cationic liposomal cancer nanovaccines: opportunities and challenges

Advancements in the field of cancer therapeutics have witnessed a recent surge in the use of liposomes. The physicochemical characteristics of the liposomes and their components, including the lipid phase transition temperature, vesicular size and size distribution, surface properties, and route of administration, play a significant role in the modulation of the immune response as an adjuvant and for loaded antigen (Ag). Cationic liposomes, concerning their potential ability to amplify the immunogenicity of the loaded Ag/adjuvant, have received enormous interest as a promising vaccine delivery platform for cancer immunotherapy. In the present review, the physicochemical considerations for the development of Ag/adjuvant-loaded liposomes and the cationic liposomes’ effectiveness for promoting cancer immunotherapy have been summarized.

On the lipid flip-flop and phase transition coupling

We measured by neutron reflectometry the loss of asymmetry in solid supported lipid bilayers, revealing an intrinsic interplay between passive lipid flip-flop and lipid phase transition.

Lipid droplet phase transition in freezing cat embryos and oocytes probed by Raman spectroscopy

ABSTRACTEmbryo and oocyte cryopreservation is a widely used technology for cryopreservation of genetic resources. One challenging limitation of this technology is the cell damage during freezing associated with the intracellular lipid droplets. We exploit a Raman spectroscopy to investigate the freezing of cumulus-oocyte complexes, mature oocytes and early embryos of a domestic cat. All these cells are rich in lipids. The degree of lipid unsaturation, lipid phase transition from liquid-like disordered to solid-like ordered state (main transition) and triglyceride polymorphic state are studied. For all cells examined, the average degree of lipid unsaturation is estimated about 1.3 (with ±20 % deviation) double bonds per acyl chain. The onset of the main lipid phase transition occurs in a temperature range from −10 to +4 °C and does not depend significantly on the cell type. It is found that lipid droplets in cumulus-oocyte complexes undergo an abrupt lipid crystallization, which not completely correlate with the ordering of lipid molecule acyl chains. In the case of mature oocytes and early embryos obtainedin vitrofrom cumulus-oocyte complexes, the lipid phase transition is broadened. In frozen state lipid droplets inside the cumulus-oocyte complexes have higher content of triglyceride polymorphic β and β′ phases (∼66%) than it is estimated for the mature oocytes and the early embryos (∼50%). For the first time, to our knowledge, temperature evolution of lipid droplets phase state is examined. Raman spectroscopy is proved as a prospective tool forin situmonitoring of lipid phase state in single embryo/oocyte during freezing.