ETD

• gelatine
• hydrogel
• mucosa
• submucosa

The large intestinal wall is composed by mucosa, submucosa, muscularis propria and serosa. It may be affected by diseases which impair mucosa and submucosa, such as ulcerative colitis (UC) and familial adenomatous polyposis (FAP). FAP and UC are currently treated with invasive surgical procedures that remove the entire large intestine. This thesis was conducted within the EU funded project TENTACLE (InnovaTivE in situ 4D biopriNTing for regenerAtion of CoLorEctal mucosa and submucosa, GA: 101191747), which aims to regenerate the colorectal mucosa and submucosa of patients affected by FAP or UC, based on in situ bioprinting. In this context, the main goals of this thesis are the synthesis, characterization and in vitro validation of the biomaterials within TENTACLE. Two different functionalized gelatines (GelNB, GelSH) have been synthesized and characterized by NMR, OPA assay and hr-MAS to assess the accuracy of the synthesis. Later, four concentrations (5%, 6%, 7.5% and 10% w/v) of GelNB+GelSH hydrogels were characterized through rheology and mechanical tests, swelling and gel fraction. The lower gelation time and dose light, render these hydrogels more suitable for cells encapsulation compared to gold standards. In addition, they have a homogeneous network and a better resistance to deformation. Ultimately, the hydrogel was biologically validated, demonstrating that the 6% w/v gel can mimic the mucosal layer. However, some future developments are required, such as the optimization and standardization of the mucosa tissue in vitro and the evaluation of the hydrogel printability in term of filament deposition, cell viability and shape fidelity.