Dendronized chitosan derivative as a biocompatible gene delivery carrier

To improve the transfection efficiency of chitosan as a nonviral gene delivery vector, a dendronized chitosan derivative was prepared by a copper-catalyzed azide alkyne cyclization reaction of propargyl focal point poly(amidoamine) dendron with 6-azido-6-deoxy-chitosan. Its structure was characterized by (1)H NMR and FTIR analyses and its buffering capacity was evaluated by acid-base titration. In particular, its complexation with plasmid DNA was investigated by agarose gel electrophoresis, zeta potential, and particle size analyses as well as transmission electron microscopy observation. Compared to unmodified chitosan, such a chitosan derivative has better water solubility and buffering capacity. Compared to commonly used polyethyleneimine (PEI, 25 kDa), it could exhibit enhanced transfection efficiency in some cases and lower cell toxicity, as confirmed by in vitro transfection and cytotoxicity tests in human kidney 293T and human nasopharyngeal carcinoma CNE2 cell lines. In addition, the effect of serum on its transfection efficiency was also studied.