Scientists write the genetic code to produce the target protein using the four letters of DNA:G,C,A and T,producing a small double helix strand of DNA about 4000 letters long.
Custom DNA is regularly used in many research projects and can be produced at many factories offshore;scientists often order it and find it at their doorstep in a small vial tucked into an envelope.
The custom DNA is then fed to E. coli bacteria that copy it hundreds of times. There are several Australian facilities that can already do this.
Those copies are then placed inside a stainless steel bioreactor – this can be as small as 50 litres – along with nucleotides,the raw material of mRNA,enzymes and chemicals to control the reaction.
Inside the bioreactor,the enzymes copy the double-stranded DNA again and again into single-stranded mRNA. The mRNA is then filtered out and is ready for the next step of vaccine production.
MRNA itself is extremely fragile,and would be quickly destroyed inside the body. The “secret sauce” of mRNA vaccines is packing the mRNA into tiny balls of fat known as lipid nanoparticles. When these fat balls hit our cells,the cells naturally reach out and pull them inside – where they release the mRNA.