Enhancing Gene\nTransfection Efficiency of Star-Shaped\nPoly(β-amino ester)s via “Top-down” Hydrolysis

Gene therapy has emerged as a potent tool for treating\na wide range\nof hereditary and acquired disorders. However, the development of\nhigh-performance nonviral gene delivery vectors remains a significant\nchallenge. Here we report the development of a new type of star-shaped\npoly(β-amino ester) (SPAE) through a “top-down”\nhydrolysis approach and demonstrate its exceptional DNA transfection\nefficiency and safety profiles. Two SPAEs with different monomer combinations\nare first synthesized using an “arm first” strategy\nand then hydrolyzed sequentially to produce h-SPAEs with varied chemical\ncompositions and molecular weights. Results demonstrate that hydrolysis\nsignificantly influences the physiological characteristics of the\nresulting h-SPAEs and h-SPAE/DNA polyplexes. Dependent on the chemical\ncomposition, h-SPAEs with low to moderate hydrolysis degrees exhibit\nsuperior gene transfection efficiency and cell viability across various\ncell types. Notably, the leading candidate, h-SPAE-1-5h, achieves\nup to 88.8% gene transfection efficiency, which was 154–257%\nhigher compared to SPAE-1. This study not only establishes an easy-to-operate\n“top-down” approach for reshaping the topological structure\nand chemical composition of SPAEs, but also identifies promising candidates\nfor effective gene transfection. This strategy can be applied to other\ncationic polymers to enhance their gene transfection performance.