4A3-Cit is an ionizable lipid used for the generation of lipid nanoparticles (LNPs). To investigate the role of unsaturated lipid tails in iLNPs, the nucleophilic amines were added to ester-based linkers, followed by Michael’s addition to the thiols to construct a library of 91 amino ionizable lipids. Such ionizable lipids were composed of an ionizable tertiary amine core, an ester-based degradable linker, and an alkylthiol tail periphery. Through in vitro and in vivo screening, the iLNPs with 4A3 core and citronellolbased (Cit) periphery can significantly increase endosome escape and delivery efficiency of mRNA, leading to 18-fold increase in protein expression compared with iLNPs without Cit periphery. Furthermore, the delivery efficiency of mRNA may be associated with the location/configuration of the unsaturated bond(s) in lipids. Although lipids with Cit periphery showed excellent membrane fusion ability to facilitate endosome escape, the fusion mechanism needs to be further clarified.

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.

S. M. Lee, Q. Cheng, X. L. Yu, S. Liu, L. T. Johnson, D. J. Siegwart, Angew. Chem. Int. Ed. 2021, 60, 5848.