Fig. 2.

(A) Present and future delivery material discovery strategies. Black ellipses represent ionizable lipid screening efforts with size of ellipse representing the number of lipids screened. (i) Small, targeted, rationally designed screen. (ii) High-throughput screen. (iii) High-throughput machine learning–guided screen. (iv) Small, targeted machine learning–guided screen. (B) The components of an LNP. (C) Prominent multicomponent reactions used to generate ionizable lipid libraries; Michael addition can use an acrylate or acrylamide. (D) Barcoded delivery screening. (E) RNA delivery nanoparticles can be targeted to specific cell types via (i) incorporation of specific ligands, (ii) antibody conjugation, or (iii) peptide conjugation.