Biodegradable and nontoxic nanogels as nonviral gene delivery systems

The development of polymeric systems with tailored properties as nonviral gene carriers continues to be a challenging and exciting field of research. We report here the synthesis and characterization of biodegradable, temperature- and pH-sensitive carbohydrate-based cationic nanogels as effective gene delivery carriers to Hep G2 cells. The temperature-sensitive property of the nanogels allows their facile complexation of DNA, while the pH-sensitive property allows the degradation of nanogels followed by the release of plasmid in the endosome. The nanogels are synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) technique and are evaluated for their DNA condensation efficacy. The gene delivery efficacies of these nanogels are subsequently studied and it is found that these cationic glyconanogels can serve as potent gene delivery vectors in hepatocytes. It is found that the gene delivery efficacies of this system are similar to that of branched poly(ethyleneimine), which is used as a positive control. Moreover, these nanogels show desirable properties for systemic applications including low toxicity and degradation in acidic environment.