Design of lipid nanoparticles for in vitro and in vivo delivery of plasmid DNA

Lipid nanoparticles (LNPs) containing distearoylphosphatidlycholine (DSPC), and ionizable amino-lipids such as dilinoleylmethyl-4-dimethylaminobutyrate (DLin-MC3-DMA) are potent siRNA delivery vehicles in vivo. Here we explore the utility of similar LNP systems as transfection reagents for plasmid DNA (pDNA). It is shown that replacement of DSPC by unsaturated PCs and DLin-MC3-DMA by the related lipid DLin-KC2-DMA resulted in highly potent transfection reagents for HeLa cells in vitro. Further, these formulations exhibited excellent transfection properties in a variety of mammalian cell lines and transfection efficiencies approaching 90% in primary cell cultures. These transfection levels were equal or greater than achieved by Lipofectamine, with much reduced toxicity. Finally, microinjection of LNP-eGFP into the limb bud of a chick embryo resulted in robust reporter-gene expression. It is concluded that LNP systems containing ionizable amino lipids can be highly effective, non-toxic pDNA delivery systems for gene expression both in vitro and in vivo.

Graphical AbstractLipid nanoparticles (LNPs) composed of amino-lipids, helper lipids, cholesterol, and polyethylene glycol lipids have gained prominence as potent siRNA-delivery vehicles. Here we explore their utility for delivery of plasmids. We first explored the role of helper lipids, and found that replacement of saturated phosphatidylcholine with its unsaturated analogues greatly improves transfection. We further showed that replacement of optimized amino-lipid DLin-MC3-DMA with DLin-KC2-DMA results in further improvements to transfection potency. Impressively, “”LNP-plasmid systems achieve robust gene expression in primary cells in vitro, and for transfection of the developing chick embryo limb-bud in vivo without observable toxicity.240