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Reproducing cardiac fibrosis: from state of the art analysis to the design of bioartificial electrospun fibers for in vitro pathological cardiac tissue modelling

Fabio Carangelo

Reproducing cardiac fibrosis: from state of the art analysis to the design of bioartificial electrospun fibers for in vitro pathological cardiac tissue modelling.

Rel. Valeria Chiono, Irene Carmagnola. Politecnico di Torino, Corso di laurea magistrale in Ingegneria Biomedica, 2020

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Heart disease is one of the most pathology present nowadays. After a stroke a lot of cardiac cells are lost, especially cardiomyocytes. Then a reparative wound process starts, including the activation of cardiac fibroblasts in myofibroblasts, the production of new extracellular matrix (ECM) and the increasing of collagen content, especially type I and III. All these events lead to myocardial fibrosis and cardiac tissue stiffening. Heart pump capacity result to be impaired and heart failure can occur. Since cardiomyocytes are not able to replicate, scar tissue will not become functional anymore, so heart function will no longer be restored. Nowadays there are no therapies that allow the regeneration of the heart and the only option is a heart transplant. However, this option shows some restrictions, since the request of heart is higher than donor availability. This push scientists to search for other strategies to solve the problem. One of that is the development of in vitro model to test drug on it rather than on animal and human. Here a research on in vitro strategies for tissue engineering and model were done to evaluate the state of the art in this field. A focus was done on strategies to create and functionalize the substrate and techniques to validate the in vitro model. Besides ways to distinguish myofibroblasts from cardiac fibroblasts were found by using specific markers such as Alpha smooth muscle actin (α-SMA), Angiotensin 1 receptor (AT1) and fibronectin extra dominant A. Then electrospinning was used to build a biomimetic scaffold for the cultivation of cardiac fibroblasts. The work started from the optimization of a previous tested set of parameters for the electrospinning of PCL (Mw=43 kDa) random fibers for cardiac fibroblasts culture. A step forward was done by testing a new set of parameters for the creation of aligned fiber scaffolds. The isotropic structure emulated the condition of ECM at the early stages of fibrosis, while the second one imitated the following steps of fibrosis in which the contraction and the stress in the heart make the orientation anisotropic. A gelatin (G) layer was deposit on scaffolds to improve their wettability and biomimecity. In addition, as gelatin is extracted from collagen denaturation, it can better mimic fibrotic ECM. G was linked to scaffolds through a mussel-inspired approach, by using 3,4-Dihydroxy-DL-phenylalanine (DOPA) as an adhesive pre-coating. Physic-chemical and morphological analysis were carried out to assess the quality of scaffold and functionalization process. Degradation analysis showed PCL scaffolds degraded only in a few percentages, remaining stable during the range of time considered (4.25% at 28 days). Contact angle at 5s displayed the correct functionalization with G, since the contact angle had the major decrease with the double layer DOPA/G (62°). Another test that gave feedback about the functionalization was the acid orange assay. The number of moles per cm2 was assessed by this analysis in three-time steps (1gg, 3gg an 7gg) to characterize the stability of the coating during this period. DOPA/gelatin scaffold gave the best results in all the three-time steps (0.0043 n mol/cm2 at 1 day, 0.0033 n mol/ cm2 at 3 days and 0.0046 n mol/ cm2 at 7 days).

Relators: Valeria Chiono, Irene Carmagnola
Academic year: 2019/20
Publication type: Electronic
Number of Pages: 74
Corso di laurea: Corso di laurea magistrale in Ingegneria Biomedica
Classe di laurea: New organization > Master science > LM-21 - BIOMEDICAL ENGINEERING
Aziende collaboratrici: UNSPECIFIED
URI: http://webthesis.biblio.polito.it/id/eprint/14943
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