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Bioreducible PEI-functionalized glycol chitosan: A novel gene vector with reduced cytotoxicity and improved transfection efficiency

Taranejoo, Shahrouz, Chandrasekaran, Ramya, Cheng, Wenlong, Hourigan, Kerry
Carbohydrate polymers 2016 v.153 pp. 160-168
DNA, buffering capacity, chitosan, cytotoxicity, disulfide bonds, gel electrophoresis, genes, transfection
Non-viral gene delivery has been well recognised as a potential way to address the main safety limitations of viral gene carriers. A new redox-responsive PEI derivative was designed, synthesized and evaluated for non-viral delivery applications of GFP DNA. Glycol chitosan was covalently attached to highly branched LMW PEI via bio-cleavable disulfide bonds to synthesize a new redox-responsive gene carrier (GCS-ss-PEI). Results showed the enhanced buffering capacity of GCS-ss-PEI, 43.1%, compared to the buffering capacities of both LMW PEI and HMW PEI, 23.2% and 31.5%, respectively, indicating more likely endosomal escape of the entrapped gene for GCS-ss-PEI. Moreover, electrophoretic gel retardation assay, performed to investigate the binding strength of GCS-ss-PEI to GFP DNA, showed stronger complexation with GFP DNA in GCS-ss-PEI at non-GSH condition. Employing GCS and incorporation of disulfide bonds in the structure of the PEI-based gene carrier resulted in improved redox-responsivity, reduced toxicity, enhanced endosomal escape and GFP DNA transfection. The facilitated intracellular gene release along with excellent redox-responsive characteristics and dropped cytotoxicity suggests the potential of GCS-ss-PEI as a candidate for developing highly efficient and safe gene vectors.