Innovative bi-layer scaffold for Vascular Tissue Engineering

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, often associated with conditions such as atherosclerosis and aneurysms. While vascular grafts are a key treatment, current synthetic materials show limitations in small-diameter vessels due to poor biocompatibility and low long-term patency. Vascular tissue engineering (VTE) aims to overcome these limitations through the development of biomimetic scaffolds that replicate the structural and functional features of native vessels. This thesis presents the design and fabrication of an innovative bi-layer scaffold for vascular application, combining a cryogel core, composed of methacrylated hyaluronic acid (HAMA) and poly(ethylene glycol) diacrylate (PEGDA), with an electrospun outer layer made of the elastomer Pebax® 2533. The cryogel provides a porous 3D structure suitable for cell infiltration and proliferation, while the electrospun sheath enhances mechanical strength and mimics the native vessel’s fibrous architecture. Multiple optimizations were conducted on the cryogel composition, geometry and cryopolymerization parameter to assure adequate mechanical strength and preserve a consistent lumen diameter of around 2 mm. Electrospinning parameters such as voltage, flow rate, and needle–collector distance were also fine-tuned to ensure process reproducibility while achieving uniform fiber deposition and construct flexibility. Results suggest that this bi-layer system could serve as a promising candidate for smalldiameter vascular grafts, offering a combination of flexibility, strength, and cell compatibility needed for future clinical applications.