A stimuli-responsive gradient-structured membrane for dual controlled release of bioactive agents: application to chronic wound dressings

In view of elaborating a gradient-structured membrane (GSM) for differential kinetic release of antibiofilm/antibiotic agents in the context of wound dressing applications, a previously electrospun poly(vinyl alcohol) (PVA) fibrous membrane (EFM) was combined with a poly(butylene-succinate-co-adipate) (PBSA) asymmetric porous membrane (AM) via physical adhesion. Physical adhesion was promoted via surface modification of the PVA fibers involving complexation of the numerous PVA hydroxyl groups with phenyl boronic acid (PBA). This modification resulted in heightened hydrophobicity, better surface energy compatibility, and improved adhesion between the PVA EFM and the PBSA AM. Surface modification was monitored via FTIR-ATR and contact angle measurements. Increased hydrophobicity of PVA EFM and good adhesion of the latter to the AM on its porous side was confirmed. Thus, thanks to the surface modification, a gradient-structured membrane was obtained consisting of a double layer membrane comprised of a dense/macro-/micro-/nano-porous structure exhibiting high surface-to-volume ratio. Furthermore, as proof of concept, our study shows that PBA can be used as pro-drug mimic exhibiting pH sensitive release profiles in aqueous environment. Finally, a BSA (Bovine Serum Albumin) model protein was encapsulated within the porous structure and its release profile was monitored over time. Our results are promising in that they provide a new structural substrate for the dual concomitant differential controlled release of large amounts of high MW (antibiofilm proteins) and low molecular weight (antibacterial) bioactive agents.