Structure–property relationships of electrospun PU/PMMA membranes for induced membrane-inspired bone regeneration

Electrospun fibrous membranes represent a promising strategy to replicate key barrier and microenvironmental functions of the induced membrane in bone regeneration. However, achieving an optimal balance between mechanical integrity, permeability, and biological performance remains challenging. In this study, we investigated the structure–property relationships of electrospun polyurethane (PU)/poly(methyl methacrylate) (PMMA) blend membranes designed for induced membrane-inspired applications. A systematic approach was used to control polymer composition and solvent system, enabling the fabrication of homogeneous fibrous membranes with tunable properties. Uniform fiber morphology was obtained for formulations containing up to 50% PMMA (w/w), while higher contents led to brittle, non-handleable structures. Thermal analyses indicated partial miscibility and improved stability in PU/PMMA blends. Mechanical testing showed increased stiffness and tensile strength with higher PMMA content, with optimal performance observed for 50/50 and 60/40 compositions. Surface wettability and zeta potential analyses revealed composition-dependent interfacial properties. Transwell assays demonstrated selective permeability to albumin, supporting the potential for controlled diffusion of biological factors. Cytotoxicity testing (ISO 10993-5) confirmed the absence of toxic leachables, while cytocompatibility assays highlighted formulation-dependent cell responses, with pure PU and PU/PMMA (50/50) showing the most favorable profiles. Gamma sterilization (40 kGy) did not significantly alter membrane structure or performance. These findings demonstrate that PU/PMMA electrospun membranes can be rationally designed to achieve a functional balance between mechanical robustness, permeability, and cytocompatibility, supporting their potential as induced membrane-mimicking materials for one-stage bone regeneration strategies.