Engineering articular cartilage using newly developed carrageenan based hydrogels =Desenvolvimento de novos hidrogéis baseados em carragenina para aplicação em engenharia de cartilagem articular

摘要

Articular cartilage holds specific functionality in the human body creating smooth gliding areas and allowing the joints to move easily without pain. However, due to its avascular nature and to the low metabolic activity of the constituent cells-the chondrocytes, cartilage has a low regenerative potential. The current surgical options to treat damaged cartilage are not long lasting and involve frequent revisions. Tissue engineering may provide an alternative approach for cartilage repair, involving the use of hydrogels which can act as a temporary artificial matrix for encapsulated cells, supporting their growth and inducing the extracellular matrix (ECM) production. The use of hydrogels is regarded as advantageous for cartilage tissue engineering because they provide similar environment to the native ECM where cells reside. Up to date, many different hydrogel systems based on natural polymers have been developed for cartilage regeneration. Among these systems, marine polysaccharides origin hydrogels have received increasing attention since they are seen as an inexpensive potential source of material with owing to their specific characteristics and composition.;In the present PhD thesis it was investigated the potential of carrageenan, a sulphated polysaccharide that can be extracted from red algae, as an alternative hydrogel for cartilage regeneration. Carrageenans offer appealing assets for cell encapsulation/delivery, derived from their chemical composition and gelation process. Therefore, the main aims of this thesis were: - develop and characterize different blends of carrageenan with alginate, processed into different formats; - study the chondrogenic differentiation of stem cells loaded in kappa-carrageenan hydrogels; - asses the viability, proliferation and chondrogenic potential of different cell types, laden in kappa-carrageenan hydrogels; - evaluate the effect of cryopreservation methods on the viability and chondrogenic differentiation of stem cells encapsulated in kappa-carrageenan hydrogels; - study the in vitro and in vivo biocompatibility of kappa-carrageenan hydrogels.;Overall, the work developed under this thesis allowed to conclude that kappa-carrageenan hydrogels laden with human adipose derived stem cells show a great potential to be tailored to specific applications in cartilage tissue regeneration approaches. (Abstract shortened by ProQuest.).