4A2-B8-PH is an optimally designed thioketal-incorporated biodegradable ionizable lipid (TBIL) for mRNA delivery to pancreatic ductal epithelial cells. It features a 4A2 headgroup with three tertiary amines, a biodegradable thioketal-based B8 linker, and a branched PH tail. The thioketal linker enables ROS-responsive degradation in the tumor microenvironment, enhancing endosomal escape and mRNA release. In vivo, 4A2-B8-PH LNPs achieve 98.3% pancreas-specific targeting after intraperitoneal administration, with a 218-fold improvement in delivery efficiency compared to previous benchmarks. It successfully transfects 30.5% of pancreatic ductal epithelial cells and induces complete tumor regression in orthotopic PDAC models via IL-12 mRNA therapy, demonstrating high efficacy and safety.
