BPS2026 – pH-responsive structural transformations in GMO-based ionizable lipids to inform lipid nanoparticle design

While lipid nanoparticles (LNPs) are potent drug delivery vectors, endosomal escape remains a significant roadblock to efficient delivery. LNPs featuring inverse hexagonal or inverse cubic structures or pH-sensitive lipids have shown enhanced delivery over classic liposomal carriers. In hopes of leveraging both the structural and pH-sensitive handles, we have synthesized an ionizable glycerol monooleate (iGMO), which displays pH-sensitive transitions encompassing inverse cubic and hexagonal crystal structures. Here, we explore pH-dependent transitions in iGMO and compare this with behavior of iGMO-based LNPs through SAXS, Cryo-EM, and in vitro assays to measure fusogenicity with model early endosome membranes. Further, we characterize endosomal trafficking pathways of iGMO-based LNPs through immunofluorescence microscopy in contrast to previously reported cuboplexes, lipoplexes, and ionizable lipid LNPs.