Abstract
ABSTRACT
The packaging of RNA in lipid nanoparticles for protection and delivery was key for the development of mRNA vaccines and therapeutics. Formulation requires the addition of a variety of lipids (including cationic) in high amounts to form complexes with the negatively charged RNA. While this approach was successful for the development of RNA vaccines, it represents a major challenge for future developments. Increasing the lipophilicity of RNA is one possible approach to reducing the amount of lipid required. In nature, geranyl‐2‐thiouridine occurs at the “Wobble” position 34 of certain bacterial tRNAs. This work details investigations into geranylated oligonucleotides and their interactions with lipids. We developed an efficient post‐synthetic procedure for oligonucleotide geranylation in aqueous solutions using a geranyl‐sulfonium salt. We discovered that the geranyl‐modification can be replaced by thiol‐nucleophiles, enabling a reversible switch of the hydrophobic character of the oligonucleotides. We show that the geranyl‐modified oligonucleotides anchor onto neutral membrane structures and oil droplets. Oligonucleotides bound to the outer surface of neutral liposomes can flip to the inner membrane surface by freeze‐thaw cycles, leading to a protective effect against enzymatic or chemical degradation. Our work expands the scope of oligonucleotide lipidation strategies, which are of great interest in RNA delivery systems.