2022 Annual Meeting
Understanding the Process of Post-Loading Lipid Nanoparticles with Oligonucleotides
Lipid nanoparticles (LNPs) have demonstrated their growing importance within the medical field with the examples of Onpattro and the SARS-CoV-2 mRNA vaccines. A major limitation of current COVID vaccines are the requirement of cold chain handling (-40 C Moderna, -70 C Pfizer). Processes that would enable mRNA LNPs production that avoid cold chain requirements would be a major advance. In this work we have approached that challenge by developing post-loading of lipid nanoparticles with mRNA as a way to avoid the cold chain problem. Neither lyophilized mRNA nor empty lipid nanoparticles require stringent cold-chain handling. By combining the two components at the site of administration, i.e., in a process we denote as âpost-loadingâ, cold chain handling can be avoided. The Princeton Confined Impinging Jet (CIJ) mixers are used to produce LNPs using Flash NanoPrecipitation (FNP). In these turbulent mixers (Reynolds number>5000), an organic solvent streamâcontaining the lipidsâand an aqueous anti-solvent stream which may contain RNA are rapidly mixed. Through this scalable process LNPs are formed only at the proper compositions and flow rates of the fluid streams. Through a series of size, zeta, encapsulation efficiency, and scattering studies, we show how effective parameters can be tuned to produce 60 to 80 nm LNPs that co-encapsulate mRNA or that produce empty lipid nanoparticles. These co-encapsualted mRNA LNPs are compared with empty lipid nanoparticles that are electrostatically loaded with mRNA in a post-loading step.