As a key nonviral
gene therapy vector, poly(β-amino ester)
(PAE) has demonstrated great potential for clinical application after
two decades of development. However, even after extensive efforts
in structural optimizations, including screening chemical composition,
molecular weight (MW), terminal groups, and topology, their DNA delivery
efficiency still lags behind that of viral vectors. To break through
this bottleneck, in this work, a thorough investigation of highly
branched PAEs (HPAEs) was conducted to correlate their fundamental
internal structure with their gene transfection performance. We show
that an essential structural factor, branch unit distribution (BUD),
plays an important role for HPAE transfection capability and that
HPAEs with a more uniform distribution of branch units display better
transfection efficacy. By optimizing BUD, a high-efficiency HPAE that
surpasses well-known commercial reagents (e.g., Lipofectamine 3000
(Lipo3000), jetPEI, and Xfect) can be generated. This work opens an
avenue for the structural control and molecular design of high-performance
PAE gene delivery vectors.