MRNA vaccine | LNP delivery system technology introduction and excipients supply
October 28,2021.
LNP delivery system The major COVID-19 vaccine technology routes currently under development worldwide include inactivated vaccines, mRNA vaccines, adenovirus vaccines and recombinant protein vaccines. As a new vaccine technology in the market, mRNA vaccine is also one of the most important COVID-19 vaccines in the world at present. As a new technology, why can mRNA vaccine be widely administered around the world? One important reason is that it has a very high effective protection rate. The two available mRNA vaccines have an effective protection rate of more than 90%, and BioNTech's mRNA vaccine, produced in collaboration with Pfizer, has an effective protection rate of 95%.Since vaccination began, the daily positive rate in the United States has dropped from 20 percent to 1 to 2 percent. MRNA transmits the genetic information for producing an antigen to the cells that make the protein. These cells then present the antigen to their surfaces, triggering the specific immune response needed. Eventually, when a virus invades, the immune system recognizes specific antigens and quickly and specifically attacks the virus to prevent infection. MRNA technology can not only be used as a preventive vaccine to prevent the spread of infectious diseases, but also as a therapeutic drug to treat some serious diseases, such as cancer and AIDS, due to its ability to spontaneously stimulate human immunity. MRNA has large molecular weight, strong hydrophilicity and high biological activity, but its single chain structure makes it extremely unstable and easy to be degraded, and delivery through the membrane with negative charge on the surface is also difficult. MRNA must enter the cell to encode antibodies, and the enzyme degradation and cell membrane barrier in the process of entering the cell are the biggest challenges that affect its delivery efficiency and transfection efficiency. Special modification or package delivery systems are required to achieve intracellular expression of mRNA. At present, Lipid nanoparticle (LNP) is commonly used as a carrier to deliver mRNA .Lipid nanoparticles mainly contain four components: ionizable lipids, neutral helper lipids, cholesterol, and PEGylated lipid. The neutral helper lipids are usually saturated phospholipids, which support the formation of the lamellar lipid bilayer and stabilize its structure arrangement. Cholesterol had strong membrane fusion, which promoted the intracellular uptake of mRNA and cytoplasmic entry. Pegylated lipids are located on the surface of lipid nanoparticles, improving their hydrophilicity and avoiding rapid removal by the immune system, preventing particle aggregation and increasing stability. The most critical excipients are ionizable cationic lipids, which are decisive factors in the efficiency of mRNA delivery and transfection. Mechanism of LNP mRNA delivery: before entering cells, cationic lipids can realize electrostatic complexation with negatively charged mRNA molecules to form complex...
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