Transfection activity of layer-by-layer plasmid DNA/poly(ethylenimine) films deposited on PLGA microparticles.

Layer-by-layer (LbL) assemblies of DNA and polycations on the surface of colloidal templates can be used for gene delivery. Plasmid DNA encoding for secreted alkaline phosphatase (SEAP) was used to deposit LbL films with poly(ethylenimine) (PEI) on the surface of polystyrene and poly(lactide-co-glycolide) microparticles. The formation of LBL films was confirmed by zeta potential analysis and fluorescence and atomic force microscopy techniques. The LbL particles were rapidly internalized in a dose-dependent manner by J774.1 murine macrophages. Transfection activity of the LbL particles was evaluated in J774.1 cells using three different doses (5, 10, 25 particle per cell). The levels of SEAP expression increased with increasing dose but were lower than transfection levels mediated by control PEI/DNA polyplexes at corresponding DNA doses. The LbL particles reported here present a promising platform for delivery of DNA to phagocytic cells.