Architecting asymmetry: a multilayer Janus fibrous membrane with in situ hydrogel coating for long-term anti-adhesion and enhanced peritoneal repair.

Postoperative abdominal wall adhesion remains a significant clinical challenge, as existing mesh materials are prone to infection and adhesion. Although bacterial cellulose (BC) offers excellent biocompatibility and strength, its relatively weak biological activity and inability to prevent long-term adhesion limit its application. This study presents a novel COBF Janus membrane designed to address these limitations through a bilateral anisotropic structure. On one side, a multifunctional polysaccharide hydrogel was in-situ synthesized via negative pressure adsorption onto a modified fiber membrane (OB) matrix. This hydrogel-coated surface provides robust tissue adhesion, facilitating cell migration and collagen deposition for effective repair. Conversely, the opposite side is engineered for anti-adhesion by immobilizing iron ions (Fe3+) that chelate with the carboxyl groups (-COO-) on the OB surface. This crucial modification effectively blocks the carboxyl groups, preventing them from forming covalent bonds with amino groups (-NH₂) on tissue surfaces, which is a primary mechanism of postoperative adhesion. Initially, this iron-functionalized (OBF) surface provides a passive anti-adhesion barrier. Over time, the membrane's multi-level pore structure further promotes organized tissue remodeling and vascularization, leading to the reconstruction of a intact peritoneum and sustained anti-adhesion efficacy. Experimental results confirm that the COBF Janus membrane exhibits superior anti-adhesion performance at both 4 and 12 weeks, demonstrating its great potential as a advanced abdominal wall repair material.