Preparation and Optimization of PBAT-Based Scaffolds via Melt Electrowriting for Bone Tissue Engineering

Poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable and biocompatible aliphatic–aromatic copolyester, possesses favorable mechanical properties that make it a promising candidate for bone tissue engineering (BTE) scaffolds. However, conventional processing techniques for PBAT cannot produce scaffolds with both a high porosity and controllable microstructures, which limits its application in BTE. This study aimed to address this issue by using melt electrowriting (MEW) to prepare PBAT scaffolds with high porosity and adjustable microstructures. The feasibility of MEW for processing PBAT was first demonstrated, followed by parameter optimization. The ideal processing conditions were determined to be a collector speed of 60 mm/s, a voltage of 1.8 kV, and an air pressure of 4 kPa, producing fibers with an average diameter of approximately 17 μm. Subsequently, PBAT scaffolds with three distinct spacings (200, 300, and 400 μm) were fabricated. All scaffolds exhibited consistent hydrophobicity with a water contact angle of 120°. They also demonstrated excellent mechanical performance, enduring strains of over 600%. Both the tensile strength and Young’s modulus increased with decreasing fiber spacing, with the 300 μm scaffold showing the most balanced mechanical properties. The cellular compatibility and osteogenic potential of the PBAT scaffolds were further assessed. The results indicated that PBAT scaffolds supported cell adhesion, proliferation, and differentiation. Cells aligned along the scaffold fibers, facilitating directed mineralization. Among the scaffolds, the 300 μm scaffold was particularly effective, providing ample space for cell expansion and enhancing cell activity, alkaline phosphatase activity, and mineral deposition. This work represents a significant advancement in polymer processing by demonstrating, for the first time, the direct MEW fabrication of PBAT into high-performance, microarchitecturally tunable scaffolds, underscoring its potential for applications in BTE.