Sustainable Biomaterial for Tissue Engineering Applications

The development of biomaterials for tissue engineering holds immense potential in addressing critical medical challenges, while meeting the need for alternative eco-friendly solutions. This doctoral thesis explores innovative biomaterial-based approaches for two distinct tissue engineering applications: to provide faithful in vitro models of the central nervous system (CNS), and to propose an innovative solution for pediatric cranioplasty. The use of sustainable and biocompatible materials is central to these studies. By combining material science, biomedical engineering and biology I propose new approaches to overcome the limitations of most conventional solutions. Firstly, I investigated the potential of chitosan, a crustacean waste-derived biomaterial, in supporting the adhesion and neuronal differentiation of human induced pluripotent stem cells (hiPSCs) in simplified 2D in vitro models. Chitosan is renowned for its low cost, biocompatibility, biodegradability, antibacterial activity as well as its bioaffinity. In this thesis, I propose the use of chitosan as an alternative adhesion factor to Matrigel, the gold standard for inducing the neuronal differentiation of hiPSCs. Though extensively used, Matrigel derives from the extracellular matrix (ECM) of mouse sarcoma and has risen several concerns about its xenogenicity and batch-to-batch variability. Additionally, Matrigel is not able to support the survival of fully differentiated hiPSCs-derived neurons (iNeurons). In my work, I demonstrated that chitosan is not only able to support the early-stage neuronal differentiation of hiPSCS, but also the survival and maturation of iNeurons and the formation of a functional neuronal network, thus providing an alternative, green-based solution for in vitro modelling of the CNS. To further improve my work and address the need for more complex and representative in vitro CNS models, I leveraged the versatility of chitosan to propose 3D thermosensitive hydrogels that mimic the biochemical composition and characteristics of the brain ECM. The tuneable properties and ease of modification of chitosan thermogels, allow the formulation of more faithful in vitro models that support the neuronal differentiation of hiPSCs, paving the way for the development of personalised testing platforms for neuropathological studies and for the development of new drugs. Finally, I developed and leveraged a novel scaffold, derived from porcine MENiscus Decellularization (MEND), as an alternative material for pediatric cranioplasty. Traditional cranioplasty techniques offer exceptional outcomes in adult patients, however their failure rate increases dramatically in children, mainly due to higher infection and bone resorption incidence. To address the limitations in biodegradability, biocompatibility, and osteoconductivity of traditional methods, I leveraged decellularized porcine cartilage to support the osteogenic differentiation of human periosteal progenitor cells, mesenchymal-line cells that are found within the periosteum. The innovative decellularization process allow the formation of hollow channels that run cross-sectionally along MEND and which are pivotal for scaffold seeding and for the infiltration of new vasculature and cells once MEND is implanted in vivo. I studied the osteogenic potential of human periosteal progenitors and compared it to the osteogenic potential of human osteoblasts (positive control). Then I investigated ability of MEND in supporting the osteogenic differentiation of human periosteal progenitors. I demonstrated that periosteal cells differentiated within MEND show a robust osteogenic phenotype, similarly to human osteoblasts, thus being interesting candidates for cranial bone repair.Together, these studies demonstrate the versatility and potential of sustainable biomaterials in advancing tissue engineering and regenerative medicine. By addressing specific challenges in neural differentiation, 3D brain tissue modelling, and in pediatric cranioplasty, this work contributes to the development of innovative, biocompatible solutions with translational potential in clinical settings.