Intranasal mRNA Delivery via Customized RNA-Polyplex Nanoparticles Enhancing Gene Expression through Photochemical Mechanisms.

Achieving effective mRNA expression in vivo requires careful selection of an appropriate delivery vehicle and route of administration. Among the various routes of administration, intranasal administration has received considerable attention due to its ability to induce potent immune responses. In this context, we designed a specialized cationic polymer tailored for delivery of mRNA into the nasal cavity. These polymers are designed with varying degrees of substitution in different amine groups to allow for identification of the most suitable amine moiety for effective mRNA delivery. We also incorporated a photosensitizer within the polymer structure that can trigger the generation of reactive oxygen species when exposed to light. The synthesized cationic polymer is complexed with anionic mRNA to form a polyplex. Illuminating these polyplexes with laser light enhances their escape from intracellular endosomes, stimulating mRNA translocation into the cytoplasm, followed by increased mRNA expression at the cellular level. Through intranasal administration to C57BL/6 mice, it was confirmed that these photoactive polyplexes effectively induce mRNA expression and activate immune responses in vivo using photochemical effects. This innovative design of a photoactivated cationic polymer presents a promising and reliable strategy to achieve efficient intranasal mRNA delivery. This approach has potential applications in the development of mRNA-based vaccines for both prophylactic and therapeutic purposes.