Neutral biodegradable lipid-envelope-type nanoparticle using vitamin A-Scaffold for nuclear targeting of plasmid DNA.

Biomembranes and cytoplasm, a diffusion-limited region for nanoparticles are critical barriers to be overcome for the successful gene delivery. We herein report on a neutral, and intracellularly degradable lipid nanoparticle (LNP), containing encapsulated plasmid DNA (pDNA) that can be effectively delivered to the nucleus. A key material component in this particle is a vitamin A-scaffold SS-cleavable Proton-Activated Lipid-like Material ((SS)PalmA), which contains tertiary amine groups as proton sponge units that can respond to the acidic pH in endosomes, disulfide bonding for programmed collapse in the cytoplasm, and retinoic acid (RA) as a hydrophobic unit for assembly into LNP. LNP prepared using (SS)PalmA (LNP(PalmA)) exhibited a 15-fold higher gene expression activity compared to particles prepared with a simple acyl chain (myristoyl group)-scaffold one (LNPPalmM). Intracellular imaging studies revealed that LNP(PalmA) unexpectedly showed excessive endosome-disruptive characteristics. Furthermore, the decapsulation of pDNA slowly, but successively occurred in parallel with peri-nuclear accumulation. Nuclear targeting was blocked in the presence of native RA. Collectively, LNP(PalmA) is an intelligent particle that passes through the cytoplasm in particle form with the aid of the intrinsic nuclear transport system of RA, and thereafter releases its encapsulated pDNA for effective gene expression.