Optimized biomimetic minerals maintain activity of mRNA complexes after long term storage.

mRNA therapeutics can be readily designed, manufactured, and brought to scale, as demonstrated by widespread global vaccination against COVID-19. However, mRNA therapies require cold chain shipment and storage from manufacturing to administration, which may limit them to affluent communities. This problem could be addressed by mimicking the known ability of mineralized fossils to durably stabilize nucleic acids under extreme conditions. We synthesized and screened 40 calcium-phosphate minerals for their ability to store and maintain the activity of lyophilized mRNA complexes. The optimal mineral formulation incorporated mRNA complexes with high efficiency (77 %), and increased mRNA transfection efficiency by 5.6-fold. Lyophilized mRNA complexes stored with the optimized mineral formulation for 6 months at 25 °C were 3.2-fold more active than those stored with state-of-the-art excipients, but without a mineral. mRNA complexes stored with minerals at room temperature did not decline in transfection efficacy from 3 days to 6 months of storage, indicating that minerals can durably maintain activity of therapeutic mRNA complexes without cold chain storage. STATEMENT OF SIGNIFICANCE: Therapeutic mRNA, such as mRNA COVID-19 vaccines, require extensive cold chain storage that limits their general application. This work screened a library of minerals to maintain the activity of mRNA complexes with freeze-drying. The optimized mineral was able to maintain mRNA activity up to 6 months of storage at room temperature outperforming current methods of freeze-drying therapeutic mRNA complexes.