| 초록 |
Crosslinked bioreducible polymers, PPI–CBAs, are synthesized by Michael-type polyaddition of polypropylenimine (PPI) and cystaminebisacrylamide (CBA) for gene delivery systems. PPI–CBAs could form nano-sized polyplexes, which show high stability even in reducing condition probably due to the re-crosslinking. PPI–CBAs show high transfection efficiency comparable to PEI25k in serum condition. However, cytotoxicity of PPI–CBAs is increased with the increase of concentration and crosslinking degrees of PPI–CBAs. Decrease of glutathione (GSH) levels and the following increase of reactive oxygen species (ROS) levels are also observed. PPI–CBA polyplexes also could induce the similar effects. These results suggest that the cytotoxicity of bioreducible polymers may be closely related with the polymer structures and that reduction of intracellular GSH and following increase of intracellular ROS may induce cytotoxicity by oxidative stress. |
