Stealthy lipid nanoparticles give mRNA vaccines a makeover

A new material developed at Cornell University could significantly improve the delivery and effectiveness of mRNA vaccines by replacing a commonly used ingredient that may trigger unwanted immune responses in some people. Thanks to their ability to train cells to produce virus-killing proteins, mRNA vaccines have gained popularity over the last five years for their success in reducing the severity of COVID-19 infection.

One method for delivering the mRNA to cells is by packaging it inside fatty spheres, called lipid nanoparticles, that protect it from being degraded. However, a common component of lipid nanoparticles called poly-ethylene glycol (PEG) can provoke immune responses in some individuals, leading researchers to search for more biocompatible materials.

Shaoyi Jioang, professor of biomedical engineering, is working to replace the PEG component of lipid nanoparticles with a more adaptable and stealthy option. The research is published in the journal Nature Materials.

Most people's immune systems are already primed to fight PEG. Prior research shows that a majority of people have anti-PEG antibodies "from people being exposed to PEG in so many commercial products like shampoo and toothpaste," said Jiang, adding that this widespread exposure may explain why the body is so quick to flag PEG as a threat.

To solve this, Jiang has developed lipid nanoparticles that use a zwitterionic polymer, a crucial alternative to PEG, enhancing the performance and biocompatibility of the system.

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