Transfection Potency of Lipid Nanoparticles Containing mRNA Depends on Relative Loading Levels.

When formulating mRNA into lipid nanoparticles (LNP), various copy numbers of mRNA are encapsulated, leading to a distribution of mRNA loading levels within the LNPs. It is unclear whether the mRNA loading level affects the functional delivery of the message. Here we show that depending on the mRNA loading level, LNPs exhibit distinct mass densities and can be fractionated via ultracentrifugation.

Delivery vehicle and route of administration influences self-amplifying RNA biodistribution, expression kinetics, and reactogenicity.

Self-amplifying RNA (saRNA) is a next-generation RNA platform derived from an alphavirus that enables replication in host cytosol, offering a promising shift from traditional messenger RNA (mRNA) therapies by enabling sustained protein production from minimal dosages. The approval of saRNA-based vaccines, such as the ARCT-154 for COVID-19 in Japan, underscores its potential for diverse therapeutic applications, including vaccine development, cancer immunotherapy, and gene therapy. This study investigates the role of delivery vehicle and administration route on saRNA expression kinetics and reactogenicity.