Disulfide-crosslinked triblock polyampholyte vesicles as a reducible platform for polyplex-based nucleic acid delivery.

Polyion complex (PIC) vesicles are attractive carriers for mRNA delivery, yet their assembly is often compromised by charged cargos that disrupt the electrostatic interactions required for vesicle formation. Here, we report triblock polyampholyte vesicles (TBPVs) that encode preferential polymer-polymer interactions, enabling robust vesicle assembly independent of cargo-mediated disruption. Constructed from poly(ethylene glycol)-b-poly(L-lysine)-b-poly(aspartic acid) copolymers, TBPVs encapsulate both free mRNA and pre-condensed mRNA polyplexes while preserving vesicle integrity. Notably, the TBPVs encapsulating pre-condensed mRNA polyplexes demonstrated significant protein expression both in vitro and in vivo. Disulfide crosslinking of the vesicular membrane further confers stability under physiological conditions, while providing redox responsiveness for intracellular disassembly and cargo release. Systemically administered SS-TBPVs loaded with mRNA polyplexes enable detectable hepatic transgene expression in vivo. These findings support triblock polyampholyte PIC vesicles as a versatile and cargo-tolerant platform for polyplex-based nucleic acid delivery.