Layer by layer surface engineering of poly(lactide-co-glycolide) nanoparticles for plasmid DNA delivery

The administration of exogenous DNA has been proposed as a promising therapeutic approach for a variety of diseases. Unfortunately, exogenous DNA is unable to spontaneously penetrate mammalian cells. Although viral vectors facilitate DNA delivery at high transfection efficiency, they are restricted for in vivo applications as they could potentially induce immunogenicity and mutagenesis. To overcome the clinical challenge of viral delivery, a strategy for the encapsulation of plasmid DNA on the surface of poly(lactide-co-glycolide) nanoparticles (PLGA NPs) is shown. Plasmid green fluorescence protein (pEF-GFP) or piggybac transposon (PBCAG-eGFP) are assembled on the surface of PLGA NPs through layer by layer technique. The assembly of pEF-GFP with biopolyelectrolytes is monitored on a planar support using a quartz crystal microbalance with dissipation. The assembly of the biopolymer multilayers on PLGA NPs is followed by zeta-potential measurements. Encapsulation of plasmid DNA within the multilayers coating is confirmed by gel electrophoresis. Cellular uptake studies on HEK293 cells revealed that PLGA NPs are taken up by cells within the first 5 hr of co-culturing. Intracellular release of cargo is confirmed by GFP expression in HEK293 cells. PLGA NPs encapsulating pEF-GFP on their surface are able to transfect similar to 20% of HEK293 cells, while those encapsulating PBCAG-eGFP can transfect up to 75% of cells after 72 hr, causing minimum to non-cytotoxic effects.