Nanoparticle-based delivery platforms for mRNA vaccine development

Conventional vaccines have saved millions of lives, and new vaccines have also been developed; however, an urgent need for an efficient vaccine against SARS-CoV-2 showed us that vaccine development technologies should be improved more to obtain prophylactic agents rapidly during pandemic diseases. One of the next-generation vaccine technologies is utilization of mRNA molecules encoding antigens. The mRNA vaccines offer many advantages compared to conventional and other subunit vaccines. For instance, mRNA vaccines are relatively safe since they do not cause disease and mRNA does not integrate into the genome. mRNA vaccines also provide diverse types of immune responses resulting in the activation of CD4+ and CD8+ T cells. However, utilization of mRNA molecules also has some drawbacks such as degradation by ubiquitous nucleases in vivo. Nanoparticles (NPs) are delivery platforms that carry the desired molecule, a drug or a vaccine agent, to the target cell such as antigen presenting cells in the case of vaccine development. NP platforms also protect mRNA molecules from the degradation by nucleases. Therefore, efficient mRNA vaccines can be obtained via utilization of NPs in the formulation. Although lipid-based NPs are widely preferred in vaccine development due to the nature of cell membrane, there are various types of other NPs used in vaccine formulations, such as virus-like particles (VLPs), polymers, polypeptides, dendrimers or gold NPs. Improvements in the NP delivery technologies will contribute to the development of mRNA vaccines with higher efficiency.