Beta-sitosterol containing lipid nanoparticles as nucleic acid delivery agents

There has been a shift in the pharma industry towards delivery of therapeutic agents such as nucleic acids that act within the cell’s cytosol, thereby creating a demand for advanced delivery vehicles, such as lipid nanoparticles (LNPs), the NPs of interest here. An important feature of intracellular delivery is that the vehicle is taken into the cell via endocytosis with the vehicle and its payload becoming engulfed in the acidic environment of the endosome from which it must escape in order for the therapeutic to exert its effect. We have recently shown that the sterol, beta-sitosterol is a more effective delivery agent than cholesterol, when used to prepare the LNP. Here we propose to use neutron reflectometry in combination with isotopic contrast variation to determine the extent of insertion of beta-sitosterol and exchange between LNPs (prepared using the cationic lipid, MC3) with model early endosomal (EEM) membranes at sub-phase pH’s of 5.5 and 6.5. The results obtained here will be extremely important in the design of improved LNPs that can escape the endosome at an early stage with their payload intact and able to exert its effect in the cytosol of the cell.