OC2-K3-E10 is an ionizable lipid for delivery of mRNA in lipid nanoparticles (LNPs). OC2-K3-E10 LNPs delivered Firefly luciferase mRNA when injected intramuscularly in mice and resulted in comparable levels of luminescence as SM-102 LNPs. LNPs were also able to deliver Cas9 mRNA and sgRNA into genetically modified mice. LNPs containing OC2-K3-E10 were able to encapsulate four-fold more mRNA copies per particle compared to SM-102.