Biomimetic Trypsin-Responsive Structure-Bridged Mesoporous Organosilica Nanomedicine for Precise Treatment of Acute Pancreatitis.

Developing strategies to target injured pancreatic acinar cells (PACs) in conjunction with primary pathophysiology-specific pharmacological therapy presents a challenge in the management of acute pancreatitis (AP). We designed and synthesized a trypsin-cleavable organosilica precursor bridged by arginine-based amide bonds, leveraging trypsin's ability to selectively identify guanidino groups on arginine via Asp189 at the active S1 pocket and cleave the carboxy-terminal (C-terminal) amide bond via catalytic triads. The precursors were incorporated into the framework of mesoporous silica nanoparticles (MSNs) for encapsulating the membrane-permeable Ca chelator BAPTA-AM with a high loading content (∼43.9%). Mesenchymal stem cell membrane coating and surface modification with PAC-targeting ligands endow MSNs with inflammation recruitment and precise PAC-targeting abilities, resulting in the highest distribution at 3 h in the pancreas with 4.7-fold more accumulation than that of naked MSNs. The outcomes transpired as follows: After bioinspired MSNs' skeleton biodegradation by prematurely and massively activated trypsin, BAPTA-AM was on-demand released in injured PACs, thereby effectively eliminating intracellular calcium overload (reduced Ca level by 81.3%), restoring cellular redox status, blocking inflammatory cascades, and inhibiting cell necrosis by impeding the IκBα/NF-κB/TNF-α/IL-6 and CaMK-II/p-RIP3/p-MLKL/caspase-8,9 signaling pathways. In AP mice, a single dose of the formulation significantly restored pancreatic function (lipase and amylase reduced more by 60%) and improved the survival rate from 50 to 91.6%. The formulation offers a potentially effective strategy for clinical translation in AP treatment.