A guanidinylated bioreducible polymer with high nuclear localization ability for gene delivery systems

Guanidinylated bioreducible polymer (GBP) was developed for gene delivery systems utilizing cellular penetrating ability of guanidine groups. GBP could retard pDNA from a weight ratio of 5 completely in agarose gel electrophoresis but pDNA was released from GBP polyplexes even at a weight ratio of 20 in reducing condition (2.5 mm DTT) due to their biodegradation. GBP also could construct 200 nm-sized and positively charged (∼30 mV) polyplex nanoparticles with pDNA. The cytotoxicity of GBP was found to be minimal and GBP showed about 8 folds improved transfection efficiency than a scaffold polymer, poly(cystaminebisacrylamide-diaminohexane) (poly(CBA-DAH)) and even higher transfection efficiency than PEI25k in mammalian cell lines. Its high cellular uptake efficiency (96.1%) and strong nuclear localization ability for pDNA delivery due to the structural advantage of bioreducible polymer and guanidine groups were also identified, suggesting GBP is a promising candidate for efficient gene delivery systems.