Gene Delivery Mediated by Backbone-Degradable RAFT Copolymers

Mulay, P. B.; Radford, D. C.; Rondon, B.; Favetta, B.; Schuster, B. S.; Niu, J.; Gormley, A. J.

doi:10.1101/2025.10.17.682953

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bioRxiv · 10.1101/2025.10.17.682953

Gene Delivery Mediated by Backbone-Degradable RAFT Copolymers

Mulay, P. B.·Radford, D. C.·Rondon, B.·Favetta, B.·Schuster, B. S.·Niu, J.·Gormley, A. J.

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Abstract

Cationic polymers present an attractive platform for gene delivery. However, these highly charged macromolecules can also lead to cytotoxicity. Therefore, there is a strong unmet need to develop efficacious polymeric gene delivery vehicles with high biocompatibility. Here, we leveraged recent advances in polymer chemistry to develop backbone-degradable cationic copolymers and evaluate their potential as gene delivery vehicles. Specifically, polycations were prepared via copolymerization with macrocyclic allylic sulfides which can participate in PET-RAFT polymerization via radical ring-opening cascade copolymerization to install degradable backbone segments. A polymer library with varying degradability was prepared and evaluated using a model GFP plasmid to transfect U-2 OS cells. Incorporation of degradable groups into the copolymer backbone improved transfection efficiency 10-fold at low amine/phosphate (N/P) ratios without increasing cytotoxicity, thereby enhancing their value as gene delivery carriers. We hypothesize that degradability may enhance the complexs disassembly kinetics in the cytosol, enabling more efficient payload release.

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Mulay, P. B., Radford, D. C., Rondon, B., Favetta, B., Schuster, B. S., Niu, J., Gormley, A. J.. 2025-10-17. Gene Delivery Mediated by Backbone-Degradable RAFT Copolymers. https://doi.org/10.1101/2025.10.17.682953

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