Lloyd B. Jeffs, Lorne R. Palmer, Ellen G. Ambegia, Cory Giesbrecht, Shannon Ewanick, and Ian MacLachlan (Protiva Biotherapeutics Inc., Burnaby, British Columbia) develop an extrusion-free method for manufacturing lipid nanoparticles: instead of the slow process of forcing liposomes through calibrated membranes (extrusion), they combine a flow of lipids dissolved in ethanol with an aqueous flow of nucleic acid in a T-shaped mixing chamber. Instantaneous dilution of the ethanol below the lipid-solubility threshold generates monodisperse vesicles (under 200 nm) with encapsulation efficiencies above 80%, quickly, reproducibly, and — crucially — scalably to industrial volumes. The original paper encapsulates DNA plasmids, not messenger RNA. However, the T-junction mixing method described here is, according to direct references in later literature on manufacturing mRNA vaccines against COVID-19, the technical basis of the mixing process by which the lipid nanoparticles carrying mRNA in those vaccines are assembled today — later scaled up with microfluidic devices, but preserving the same principle of instantaneous dilution via an ethanol jet.