this study discusses the effect of complexes of chitosan grafted polyethylenimine(ch-pei) with plasmid dna on viability of mesenchymal stem cells(mscs) derived from human marrow. ch-pei/pdna nanoparticles were synthesized through the complex coacervation method using pires plasmid containing green fluorescent protein (gfp) gene. to confirm the complexation, samples were run through an agarose g...