Synergistic Effectof Guanidinium and Tertiary AmineGroups on Boosting Gene Delivery

The lack of safe and efficient delivery vectors remains a major bottleneck in nucleic acid therapeutics, limiting clinical translation. In this study, by incorporating the synergistic effects of guanidinium and tertiary amine functional groups, a new versatile branched poly(β-amino ester) (PAE)-based delivery system was designed and developed, resulting in enhanced nucleic acid (DNA/mRNA) delivery. The synergistic interactions between these functional groups were systematically analyzed using 2D-NMR, AFM, TEM, and photophysical characterization. The results show that self-assembly occurs when polymers containing different functional groups are mixed, which changes the interactions between molecules and significantly affects the structure of the polyplex. This synergy was found to significantly enhance cellular uptake, contributing to improved transfection efficiency. Compared to the leading commercial reagents (Lipofectamine 3000, jetPEI, Xfect, and Lipofectamine MessengerMAX), the optimized polymeric vector formulations demonstrated superior transfection efficiency <i>in vitro</i> with both DNA and mRNA. Their high transfection performance was also confirmed <i>in vivo</i>, along with reduced cytotoxicity and tunable organ-targeting property.