Background: Successful delivery of gene-editing tools using nano-carriers is dependent
on the ability of nanoparticles to pass through the cellular membrane, move through the cytoplasm,
and cross the nuclear envelope to enter the nucleus. It is critical that intracellular nanoparticles interact
with the cytoskeletal network to move toward the nucleus, and must escape degradation pathways
including lysosomal digestion. Without efficient intracellular transportation and nuclear entry,
nanoparticles-based gene-editing cannot be effectively used for targeted genomic modification.
Objective: We have developed nanoparticles with a low molecular weight branched polyethylenimine
lipid shell and a PLGA core that can effectively deliver plasmid DNA to macrophages for
gene editing while limiting toxicity.
Methods: Core-shell nanoparticles were synthesized by a modified solvent evaporation method
and were loaded with plasmid DNA. Confocal microscopy was used to visualize the internalization,
intracellular distribution and cytoplasmic transportation of plasmid DNA loaded nanoparticles
(pDNA-NPs) in bone marrow-derived macrophages.
Results: Core-shell nanoparticles had a high surface charge of +56 mV and narrow size distribution.
When loaded with plasmid DNA for transfection, the nanoparticles increased in size from 150
nm to 200 nm, and the zeta potential decreased to +36 mV, indicating successful encapsulation.
Further, fluorescence microscopy revealed that pDNA-NPs crossed the cell membrane and interacted
with actin filaments. Intracellular tracking of pDNA-NPs showed successful separation of pDNA-
NPs from lysosomes, allowing entry into the nucleus at 2 hours, with further nuclear ingress
up to 5 hours. Bone marrow-derived macrophages treated with pDNA/GFP-NPs exhibited high
GFP expression with low cytotoxicity.
Conclusion: Together, this data suggests pDNA-NPs are an effective delivery system for