Block copolymer/plasmid DNA micelles postmodified with functional peptides via thiol-maleimide conjugation for efficient gene delivery into plants

Introducing exogenous genes into plant cells is essential for a wide range of applications in agriculture and plant biotechnology fields. Cationic peptide carriers with cell-penetrating and DNA-binding domains successfully deliver exogenous genes into plants. However, their cell-penetrating activity may be attenuated by undesired electrostatic interactions between the cell-penetrating peptide (CPP) domain and DNA cargo, resulting in limited gene delivery efficiency. Here, we developed the block copolymer maleimide-conjugated tetra(ethylene glycol) and poly(l-lysine) (MAL-TEG-PLL). Through electrostatic interactions with plasmid DNA (pDNA), MAL-TEG-PLL formed a micelle that presented maleimide groups on its surface. The micelle enabled postmodification with cysteine-containing functional peptides, including a CPP (BP100-Cys) and nuclear localization signal (Cys-NLS) via thiol–maleimide conjugation, thereby avoiding undesired interactions. According to a comparison of gene delivery efficiencies among the pe...