The Development Process of mRNA-LNP Vaccine

mRNA vaccines have become excellent vaccine candidates during the COVID-19 pandemic because of their unique favorable characteristics, including their ability to generate nontoxic, effective immune responses and the potential for rapid design and scale-up production. More and more companies are committed to the development of mRNA-LNP vaccines. The development of mRNA-LNP vaccines mainly includes mRNA design, synthesis, encapsulation, quality testing, safety assessment, production and in vitro/in vivo functional validation.

Figure 1. Schematic of mRNA-LNP process development.

mRNA-LNP Production

A plasmid containing the nucleic acid sequence of the virus is injected into E. coli. Then propagated and fermented, and the purified ring plasmid is collected for quality control to ensure the safety of subsequent vaccine production. The viral genes in linear segments were cut from the circular plasmid using enzymatic technology, transcribed to generate mRNA using DNA as a template, and collected for chemical modification and purification. The LNP is wrapped around the mRNA using microfluidic technology, and the subsequent sterilization and filtration and canning are performed.

Figure 2. Schematic flow diagram of mRNA-LNP process development.

Figure 3. Quality control (QC) testing of the mRNA-LNP vaccine development process.

Preclinical Safety Evaluation

The mRNA vaccine development involves a preclinical non-clinical part of the study, which mainly focuses on the quality and safety of mRNA for effective regulation. Functional analyses are generally performed in two parts: in vitro and in vivo. The in vitro analysis mainly includes in vitro protein expression, which is the assessment of transfection and translation efficiency. Potential toxicity of translation products also needs to be analyzed. The in vivo part of the analysis is mainly based on immunogenicity, biodistribution analysis from animal experiments. Pharmacokinetic analysis, toxicology studies, ADME, etc. are also needed. Finally, the clinical studies are phase I and II safety and phase III efficacy, as well as production monitoring and certification.

Figure 4. Schematic diagram of Preclinical safety evaluation.