Counting mRNA Copies Inside Single Lipid Nanoparticles by Breaking Them Open and Labeling

A new method allows for direct counting of mRNA copies per lipid nanoparticle (LNP), addressing limitations in current characterization techniques.

• Current techniques for measuring mRNA in LNPs struggle with accuracy due to issues with fluorescent dye interactions.
• The presented method involves lysing individual LNPs in microwells to release and directly count mRNA molecules using fluorescence microscopy.
• This approach enables the analysis of LNPs made with therapeutic grade mRNA that is not labeled.
• Two Onpattro-based LNP formulations were examined, revealing differences in average mRNA copy number, particle size, and the proportion of empty LNPs.
• Direct counting of mRNA molecules provides a complementary technique to existing methods, enhancing the characterization of LNP formulations.

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