Elucidating mRNA-Lipid Nanoparticle Formulation Efficacy using Single-Particle Fluorescence Imaging

Commonly used genetic drugs include messenger RNA (mRNA) for expressing therapeutic proteins and short interfering RNA (siRNA) for inhibiting the synthesis of pathogenic genes; however, challenges in delivering these large negatively charged molecules into cells is challenging. The use of lipid nanoparticles (LNPs) has shown to be an effective method of delivery as exemplified by the 2020 mRNA COVID-19 vaccines by Pfizer-BioNTech and Moderna. After LNPs are administered, they are taken up by cells and are transported through the endosomal pathway, where the acidic environment results in the destabilization of the LNP through fusion with the endosomal membrane. Consequently, releasing the drug. However, this process is still elusive, and many studies have shown that this endosomal fusion step is the bottleneck of effective drug delivery and efficacy. Hence, by systematically evaluating LNPs and their behaviour against representative artificial cells and live cells, we can elucidate formulations that can perform well in animals or patients. This work can create libraries of novel lipid compositions that can generate LNPs that are highly efficient at delivering the drug to their target site.