In DNA-based therapy research, the conception of a suitable vector to promote the target gene carriage, protection, and delivery to the cell is imperative. Exploring the interactions between polyethylenimine (PEI) and a plasmid DNA can give rise to the formation of suitable complexes for gene release and concomitant protein production. The nanosystems formulation method, based on coprecipitation, seems to be adequate for the conception of nanoparticles with suitable properties (morphology, size, surface charge, and pDNA complexation capacity) for intracellular applications. The developed systems are able of cell uptake, intracellular trafficking, and gene expression, in an extent depending on the ratio of nitrogen to phosphate groups (N/P). It comes that the transfection process can be tailored by this parameter and, therefore, also the therapeutic outcomes. This knowledge contributes for progresses in the development of suitable delivery systems with potential application in DNA vaccines field.
Keywords: Cationic polymers; Co-precipitation; Gene delivery; N/P ratio; Nanoparticles; Plasmid DNA; Polyplexes.