Monolithic tissue sealant membrane with covalently‑anchored NHS‑activated gelatin adhesive moieties on flexible PLCL substrate: preparation, characterization and biological performance.

Clinically available tissue sealant membranes are limited by high swelling, poor flexibility, insufficient adhesion and high cost, restricting their use in complex surgeries. Herein, a novel monolithic embedded tissue sealant membrane (IIIb) was constructed via UV‑initiated copolymerization. In this optimized formulation, NHS‑modified gelatin adhesive moieties were covalently anchored onto one side of flexible PLCL‑containing substrate, rather than simple physical lamination of two independent films (control sample IIIa prepared by method a). Although exhibiting a two‑layer‑like appearance, the resulting IIIb membrane forms an integral entity to suppress interfacial delamination. The composite membrane was prepared by sequential coating followed by UV photocrosslinking, and its chemical structure, morphology, adhesion, mechanics, swelling, degradation and biosafety were systematically evaluated. The optimized membrane showed an adhesive strength of 8.15 KPa, tensile strength of 4.9 MPa, elongation at break of 116.7%, and a low 72 h swelling ratio of 1.1%. Its degradation time was tunable from 4 to 36 weeks by regulating PLCL content to match soft tissue healing. In vitro and in vivo tests verified good cytocompatibility, hemocompatibility and negligible systemic toxicity with mild foreign body reaction. The membrane achieved a burst pressure of 11.5 ± 1.2 kPa in an ex vivo porcine stomach perforation model, satisfying clinical sealing demands. This membrane overcomes the deficiencies of commercial counterparts and holds great potential for clinical tissue sealing.