Recent advances in the development of polyethylenimine-based gene vectors for safe and efficient gene delivery.

Rational modification of PEIs with diverse functionalized segments or the development of stimuli-responsive PEIs is an appealing strategy to meet some requirements involved in gene delivery. Nevertheless, further optimization by combining the two strategies is needed for the maximized transfection efficiency and minimized side effects, shedding new light on the development of nonviral gene delivery for clinical application.