Perfluoroalkyl Chain-Modified Artificial Viral Capsid for Enhanced Intracellular Delivery of mRNA

Therapeutic mRNA has received significant attention as a new class of nucleic acid-based medicine due to its promising potential toward protein replacement therapy, vaccine development, and genome editing. Unlike DNA-based therapies, which depend on nuclear entry, mRNA works directly in the cytoplasm to produce proteins. Nevertheless, the delivery of large nucleic acids, such as mRNA, remains an unresolved challenge due to their instability, limited cellular uptake, and the cytotoxicity commonly associated with several cationic carriers. In recent years, various platforms have been developed for delivering mRNAs, including lipid nanoparticles, liposomes, dendrimers, and polyion complex micelles. Despite their success, each of these platforms faces important challenges, such as cytotoxicity, poor encapsulation efficiency and stability, limited endosomal escape, and reduced effectiveness in biological media. As a general alternative, in this study, we developed a peptide-based artificial viral capsid modified with a cell-penetrating peptide possessing perfluoroalkyl (PFA) chain (CAD^C6F13F) for the efficient and safe delivery of mRNAs into cells. The PFA-modified artificial viral capsid was formed by the self-assembly of the CAD^C6F13F-conjugated β-annulus peptide, unmodified β-annulus, and dT₂₀-SS-β-annulus, which can be hybridized with the poly(A) tail of the mRNA. Dynamic light scattering and transmission electron microscopy confirmed the formation of mRNA-encapsulated spherical capsids of approximately 200 nm in diameter. Importantly, PFA modification of the artificial viral capsid significantly improved the delivery efficiency and minimized cytotoxic effects. Fluorescence images further demonstrated that cells treated with these capsids exhibited significantly higher expression of mCherry-encoding mRNAs, indicating successful delivery and translation. Overall, our study introduces a promising viral-mimetic approach for mRNA therapeutics without compromising safety and efficiency.