Dottorato in SCIENZE FARMACEUTICHE

Titolo della tesi: Design and characterization of ECM-inspired cryogels as scaffolds for tissue regeneration

The increasing need for alternative methods to repairing critical-sized defects, and for drug in-vitro testing has driven innovations in tissue engineering (TE). In this context, TE seeks to create histological substitutes by involving pluripotent stem cells, bioactive factors and 3D scaffolds for supporting the cell process of tissues regeneration. In this context, cryogel networks made by ECM-inspired materials have shown interesting properties for fulfilling the role of TE scaffolds. Especially, this thesis will focus on the development of cryogel networks made by gelatin (Gel) and chondroitin sulfate (CS), two biopolymers emulating the ECM of several ana-tomical compartments. The experimental approach firstly focused on the production of heteropolymeric cryogels made by methacryloyl Gel (GelMA), as ECM emulator, and dextran meth-acrylate (DexMA), as enhancer of the cryogel mechanical properties. In the fabri-cation of such systems, it was possible to assess that series of variables influence the final system properties, especially the rheological properties of GelMA. Fur-thermore, despite blending to polymers aimed to produce biomechanically ex-haustive scaffolds, the heteropolymeric system resulted worsening of the me-chanical properties of produced cryogels. Therefore, other heteropolymeric sys-tems made by GelMA with Chondroitin Sulfate Methacrylate (CSMA) were investi-gated. Also in this case, GelMA/CSMA networks exhibited suboptimal mechanical characteristics, suggesting addressing other strategies for emulating the physio-logical complexity. Therefore, in the successive step it was extended this research by trying to develop hydroxyapatite-enriched (HA) GelMA and CSMA cryogels inspired to the bone ECM. Such systems can be fabricated by a one-pot cryogelation process which involves the cryogelation of GelMA or CSMA in the presence of HA. Nonetheless, the stabil-ity and the homogeneity of the crystals suspension challenge the fabrication pro-cess and might negatively affect the scaffold porosity, degradation and homogene-ity. Therefore, it was optimized a fabrication process which allows the homogene-ous dispersion of HA within the polymer network. The optimized cryogels were then physical and biologically characterized.