Lipid nanoparticle

A tiny sphere of fatty molecules, around 100 nanometres wide, that packages fragile RNA and carries it into cells.

• Unprotected RNA is destroyed in the bloodstream within minutes and is too large and charged to cross a cell membrane by itself.
• The key ingredient is a lipid that turns positively charged in the acidic pouch a cell engulfs it into, disrupting the pouch so the cargo escapes.
• LNPs made the COVID mRNA vaccines possible; given into a vein, they mostly end up in the liver, steered there by a blood protein they pick up.
• Only a small share of the cargo escapes into the cell, and reaching organs other than the liver is the main open problem.