Messenger RNA can be used for protein expression into the cells. The delivery of mRNA is the delivery of a new function that can activate a biological process. In the particular case of the CAS9 mRNA, it is simple way to make gene editing. Messenger RNAs are at the center of attention to fight cancers and for personalized medicine. However, production of capped mRNA can be a challenge. Let’s see how to face up to it here with some tips.