In the present study, a carboxymethylated guar gum-grafted-polyethyleneimine copolymer (CMGG-g-PEI) was synthesized and characterized by FT-IR, 1H NMR, XRD and zeta potential analyses. CMGG-g-PEI exhibited good binding ability with plasmid DNA (pDNA) and formed complexes with sizes ranging from 150 to 200 nm when the polymer/pDNA weight ratio was above 10 : 1. SEM analysis revealed a compact and spherical morphology of CMGG-g-PEI/pDNA complexes. The results from cytotoxicity and blood compatibility studies revealed the less toxic profile of CMGG-g-PEI. The in vitro gene transfection efficiency of the CMGG-g-PEI/pDNA complex was optimized in A549 cell and CMGG-g-PEI showed better transfection efficiency compared to the well-known standard polymer, polyethyleneimine (PEI). All the results suggested that the CMGG-g-PEI could find application as an alternative efficient gene delivery vehicle in the future.
