Objective: This research consists of preparing and examining polyethyleneimine (PEI)/ DNA nanoparticles to deliver genes of interest to bone marrow stromal cells (BMSCs) for production of growth factors.

Materials and methods: Branched PEI – plasmid DNA [cDNA containing cytomegalovirus 6 (CMV6) promoter coupled to firefly Luciferase reporter gene] nanoparticles were prepared using an established protocol. PEI solutions corresponding to various amine/phosphate (N/P) ratios (N/P ratios 1, 5, 10, 15, and 20) were formulated in purified water and added to DNA solution, yielding a final DNA concentration of 50µg/mL. The mixtures were then vortexed for 20 seconds and incubated at room temperature for 30 minutes before cell transfection. Particle size and zeta potential of the synthesized PEI/DNA complexes were measured using Malvern Nano ZS. PEI cytotoxicity and transfection efficiency of the complexes in BMSCs were examined using MTS assay for cell viability and Luciferase reporter assay, respectively. Gene expression of DNA encoding green fluorescent protein (GFP) driven by CMV6 promoter was determined through confocal microscopy.

Results: Particle size of PEI/DNA complexes over the whole range of N/P ratios was found to be less than 150 nm in diameter with a small polydispersity index (

Conclusion: PEI/DNA nanocomplexes corresponding to N/P ratio 10 are effective non-viral gene carriers for delivering target genes to BMSCs.