Lipid-based nanoparticles for nucleic acids delivery

Abstract This chapter highlights challenges and advancements in the production of lipid-based nanoparticles (LNPs) and their application in nucleic acid-based therapies. Recently, mRNA-based vaccines for COVID-19 immunization revealed that the use of nucleic acids is a promising strategy to develop treatments at high therapeutic efficiency and reduced side effects. In this context, LNPs emerged as favourable vehicles for nucleic acids delivery (like mRNA and DNA), due to their biocompatibility, bioavailability, and versatility. The four main components employed to produce LNPs loaded with mRNA are: cationic or ionizable lipids, helper lipids, cholesterol, and PEGylated lipids. Several conventional techniques have been proposed over the years to produce this kind of nanoparticles. However, they show many drawbacks that hinder the direct production of vesicles characterized by a nanometric size, high encapsulation efficiency of the active pharmaceutical ingredient, and prolonged stability. Processes assisted by supercritical fluids (in particular, supercritical CO 2 ) can represent a sustainable and interesting alternative to produce LNPs without using post-processing steps for solvent removal and size reduction that are time-consuming procedures, lead to a large loss of nucleic acids, and negatively influence the general productivity of the process.