Nature-inspired building blocks in polymer design for optimized non-viral gene delivery systems

The efficient delivery of nucleic acids into target cells has enabled genome-wide therapies like gene silencing, editing, and expression. Yet, nucleic acids are highly susceptible to degradation by nucleases and may trigger immune responses. Ideal gene carriers must protect genetic material, traverse cellular membranes, and remain biocompatible. Cationic polymers offer scalable, tunable alternatives to viral and lipid-based vectors. This work integrates natural macromolecules and bioinspired moieties into synthetic polymers to enhance gene delivery. Shielding functionalities reduced serum protein interactions and improved biocompatibility, while cholesterol moieties boosted cellular uptake, potentially via lipid raft-mediated endocytosis. Targeted delivery was achieved using fructose-functionalized bPEI, exploiting GLUT5 overexpression in breast cancer cells. Guanidinium groups were combined with pH-responsive anionic moieties to improve transfection and reduce toxicity. Differently charged diblock and triblock copolymer libraries were optimized revealing charge ratio-dependent performance in serum-rich media. Histidine-based zwitterionic polymers enhanced endosomal escape and cytocompatibility. Hydrophobic modifications using lipoic and nicotinic acids improved delivery while maintaining safety. Pullulan-based degradable polymers with hydrophobic and cationic groups achieved tunable, pH-responsive gene delivery with high viability. Overall, this strategy of combining anionic, zwitterionic, and hydrophobic modifications enabled high transfection efficiency with minimal cytotoxicity, offering a path toward safe, effective, and personalized gene therapies.