Bilayer Wound Dressing Based on Green-Synthesized ZnO-Reinforced 3D-Bioprinted Scaffolds and Electrospun PVA-Methotrexate Nanofibers

Abstract

The clinical management of complex surgical wounds requires a transition from passive barriers to multifunctional scaffolds that combine structural support with therapeutic action. This study reports a bilayer wound dressing integrating a green- synthesized zinc oxide (ZnO)-reinforced 3D-printed poly(lactic acid (PLA) framework with an electrospun poly(vinyl alcohol) (PVA) -methotrexate (MTX) nanofibrous layer. Unlike standalone electrospun mats, which often fail during handling, the 3D- printed backbone achieved a tensile strength of 34.1 ± 2.1 MPa and a Young’s modulus of 2100 ± 145 MPa, providing a 6-fold increase in mechanical resilience compared to single-layer fibrous dressings. Morphological analysis confirmed seamless interlocking at the interface, while thermal evaluation showed stabilization of the PLA phase with a Tm shift to 173.6◦C. Pharmacokinetic modeling confirmed a controlled non-Fickian diffusion mechanism ( n = 0.58), enabling sustained MTX release and reducing the burst release often seen in conventional topical systems. Green-synthesized ZnO nanoparticles imparted antibacterial activity, with inhibition zones of 15.26 and 18.23 mm against E. coli and S. aureus , respectively. In vitro cytotoxicity assays using L929 fibroblasts showed cell viability above 120% by day 14. These findings demonstrate that the proposed bilayer system offers a mechanically robust and therapeutically promising alternative to traditional wound care materials.