Rebecca Taylor / Chemistry & Biochemistry / Faculty Mentor: Kevin Schug
Lipid nanoparticles (LNPs) enable drug delivery for mRNA therapeutics, as demonstrated by the FDA-approved COVID-19 vaccines. mRNA-LNP separations present a challenge due to the opposing physicochemical properties of their components. Mac-Mod EvoSphere columns having monodisperse particle packings were selected to enhance peak shape and efficiency by minimizing eddy diffusion. Two stationary phase chemistries, C12 and C18/Ar, were used to separate empty LNPs composed of common components, such as SM-102, DSPC (a lipid), cholesterol, and DMG-PEG(2000) (a polymer) in a 50:10:38.5:1.5 molar ratio. Separation parameters were systematically optimized. Using a mobile phase with 0.1% FA and a C12 stationary phase resulted in the co-elution of SM-102 and DSPC. Resolution was improved with 0.1% TFA in water and IPA, although SM-102 and cholesterol partially co-eluted. Reducing TFA to 0.01% further improved separation between SM-102 and cholesterol. The low concentration and polydispersity of DMG-PEG led to a weak signal response, but it was still detectable, eluting before the other components. The C18/Ar column provided comparable lipid separation without the need for a TFA ion pairing agent, making it ideal for further studies with RNA-loaded LNPs. This method will be used for lipid quantitation and subsequently optimized for RNA and lipid separations.
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