A novel multilayered electrospun PCL/PCL–Gelatin/TPU–ZnO nanocomposite vascular graft to promote antibacterial activity and cell viability

The fabrication of multilayered nanocomposite vascular grafts is an emerging approach for vascular tissue engineering. In this study, three-layered vascular grafts composed of poly(ε-caprolactone) (PCL), gelatin (Gt), and thermoplastic polyurethane (TPU), incorporating 0–1 wt% zinc oxide nanoparticles (ZnO NPs), were fabricated through layer-by-layer electrospinning. ZnO NPs were synthesized via a microwave-assisted green synthesis method. The antibacterial activity and cytotoxicity of the scaffolds were evaluated to determine the optimum ZnO NPs concentration. The morphological, structural, and mechanical properties of the scaffolds were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), and dynamic mechanical analysis (DMA). Furthermore, in vitro release behaviour and biodegradability tests were performed on the samples. At the optimum cytocompatible level, the 0.5 wt% ZnO NPs-incorporated scaffold released 0.099 ± 0.004 ppm zinc ions over 72 h in PBS, exhibiting antibacterial activity (29.4 ± 2.1% Escherichia coli, 37.6 ± 4.1% Staphylococcus aureus), and 75 ± 3.85% cell viability in L929 fibroblast cells. SEM analysis indicated that the layers of the obtained scaffolds exhibited homogeneous fibrous structures. The ultimate tensile strength and the Young’s modulus of the scaffolds (incorporating 0–1 wt% ZnO NPs) were found to be in the range of 11.04 ± 0.15–11.32 ± 0.09 MPa and 7.2 ± 0.45–15.6 ± 0.35 MPa, respectively. The findings indicated that the 0.5 wt% ZnO NPs-incorporated scaffold presents the most favorable combination of mechanical strength, antibacterial activity, and biocompatibility, making it a promising candidate for vascular tissue engineering.