Performance of Polycaprolactone/Polyethylene Terephthalate Nanofiber Scaffolds in Vascular Tissue Engineering: Structural, Mechanical, In Vitro, and In Vivo Evaluation

Cardiovascular disease (CVD), primarily caused by atherosclerotic narrowing of blood vessels, is the main cause of death in the world. Although autologous grafts are considered the gold standard for vascular reconstruction, their limited availability and donor-site morbidity necessitate the development of reliable small-diameter vascular grafts (SDVGs, <6 mm), which currently suffer from thrombosis, intimal hyperplasia, and mechanical mismatch. The objective of this study was to develop and evaluate a novel composite nanofibrous SDVG with optimized mechanical and biological performance using FDA-approved polymers. SDVGs were fabricated from polycaprolactone (PCL) and polyethylene terephthalate (PET) at various weight ratios via co-electrospinning. Scaffold morphology, chemical composition, and thermal behavior were characterized using field emission scanning electron microscope (SEM), fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Mechanical properties was analyzed by tensile strength, burst pressure, and compliance assessments. In vitro biocompatibility was evaluated using NIH/3T3 fibroblast normal cell assays, and in vivo tissue compatibility was examined through subcutaneous implantation in rat models followed by histopathological analysis. The results showed that all pure and PCL/PET composite nanofibrous scaffolds exhibited uniform, bead-free nanofibers with fiber dimensions and porosity comparable to native extracellular matrix (ECM). Mechanical testing indicated that all scaffolds achieved tensile strength, compliance, and burst pressure within physiological ranges. The PCL/PET (10:90) scaffolds exhibited the highest tensile strength and Young’s Modulus, measuring 4.34± 0.38 MPa and 4.04 ± 0.445 MPa, respectively. In vitro results demonstrated enhanced cell attachment, and proliferation on composite scaffolds, with the composite PCL/PET (25:75) nanofibrous scaffold exhibiting the highest cell viability. In vivo evaluation confirmed minimal inflammatory responses and favorable tissue integration. These findings indicate that co-electrospun PCL/PET composite nanofibrous scaffolds possess suitable structural, mechanical, and biological properties for vascular tissue engineering (VTE) and as SDVG. Further long-term and hemodynamic studies in large animal models are required to support clinical translation.