Hierarchical scaffolds from a sequential melt electrowriting and electrospinning as potential wound dressings

This work investigated hierarchical polymeric scaffolds with micro- and nanometric fibrous structures fabricated through melt electrowriting (MEW) and electrospinning methods for their potential applications in wound healing. The micro-fibrous structure was fabricated by MEW using medical-grade polycaprolactone (PCL), followed by the deposition of electrospun PCL-gelatin (GEL) nanofibers onto the MEW scaffolds. The surface morphology was characterized using scanning electron microscopy (SEM). Hydrophilicity was assessed by contact angle measurements, and the chemical composition was confirmed via attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). Uniaxial tensile mechanical tests, water absorption and in vitro degradation analyses were also performed. Additionally, in vitro cell viability assays were carried out using normal human dermal fibroblasts (NHDF). As expected, the presence of PCL/GEL nanofibers enhanced hydrophilicity, and tensile tests confirmed mechanical properties suitable for wound healing applications. Additionally, water uptake and in vitro degradation studies demonstrated that the PCL/GEL electrospun layer enhanced the absorption capability of phosphate-buffered saline (PBS), which is beneficial for skin regeneration. Gelatin release analysis further indicated a time-dependent release behavior from the electrospun nanofiber layer. Furthermore, electrospun nanofibers showed higher NHDF viability, likely due to increased surface area for cell adhesion and the bioactive nature of GEL. The results confirmed that no cytotoxic effects were induced by the hierarchical scaffolds. Overall, combining MEW with electrospinning enabled the fabrication of micro- and nanometric fibrous hierarchical scaffolds with properties favorable for wound healing applications.