Modular design of dual-targeted, enzyme-responsive peptide carriers for gene drug delivery

Gene-based therapeutics, including siRNA and mRNA, offer promising strategies for disease-related gene modulation but remain limited by challenges in systemic delivery and intracellular release. We report a modularly designed peptide-based carrier capable of delivering both siRNA and mRNA in vitro and in vivo. The carrier self-assembles from three functional peptide sequences incorporating modules for lysosomal escape (RRGK and leucine repeats), tumor-associated targeting (RGDK and GYQTI), and enhanced structural stability (long-chain serine). In vitro, the siRNA@peptide complex achieved 97% cellular uptake and 75% GFP gene silencing efficiency in HeLa cells. For mRNA delivery, the carrier promoted robust GFP expression in vitro and enabled tumor-associated luciferase expression in vivo. Furthermore, systemic administration of siRNA formulated with the optimized carrier resulted in measurable gene silencing in multiple organs, confirming its in vivo functional delivery capability. Collectively, these results establish a modular peptide platform for systemic gene delivery, demonstrating effective in vivo gene expression and gene silencing while maintaining acceptable biosafety. This study provides a versatile framework for the rational development of peptide-based nucleic acid delivery systems.