Séminaire sur les biomatériaux pour l’ingénierie tissulaire

Vous êtes cordialement invités au séminaire sur les biomatériaux pour l’ingénierie tissulaire, présenté par Simona Ignat, Andreea Lazar, Iuliana Samoila, Aida Selaru, Roxana Balahura, Mirela Serban, Department of Biochemistry and Molecular Biology, University of Bucharest, Bucharest, Romania, organisé par l'ICPEES 

Thematic 1: Biomaterials for tissue engineering and regenerative medicine
Tissue engineering combines biological resources (cells) with engineered biomaterials and chemical substances that act as induction factors, in order to obtain a tissue-like structure as similar as possible to the natural counterpart. Numerous biomaterials based on natural or synthetic compounds, even a combination of both, have been designed and developed to serve as scaffolds, structures capable of mechanically supporting the cells seeded on their surface, while at the same time promoting cell proliferation and differentiation in the presence of specific induction factors. Depending on the type of tissue that requires regeneration, biomaterials are designed as such that they resemble the native extracellular matrix secreted by the cells. For example, bone tissue regeneration requires hard, porous materials and we recently evaluated some made out of hydroxyapatite, a natural compound usually found in the bones. On the other hand, adipose tissue regeneration requires soft materials, collagen for example, a natural component of soft tissue. This presentation will overview different biocompatibility studies, as well as stem cell differentiation studies in contact with biomaterials.

Thematic 2: Original materials (developed in the frame of international projects) and their biocompatibility studies
One of our studies focused on evaluating the biocompatibility and antibacterial effect of novel flexible thermoplastic polyurethane (TPU) foams enriched with different concentrations (1, 2, 5, 10 wt.%) of zinc oxide (ZnO) nanofiller. Human adipose­derived stem cells were cultivated in contact with TPU/ZnO nanocomposites, in order to study cell viability and proliferation and material cytotoxicity. Antibacterial activity of TPU/ZnO nanocomposites was tested against two gram­positive bacteria (E. faecalis, S. aureus) and two gram­negative bacteria (E. coli, P.aeruginosa). Results showed that these novel foams displayed low levels of toxicity for the cells and good biocompatibility for TPU biomaterials enriched with 2 and 5 wt.% ZnO, whereas the highest antimicrobial activity was reported for TPU/ZnO 10 wt.%.
    Another study focused on analyzing the influence of hydroxyapatite (HA) dopped with 5% magnesium (Mg) on the physical, chemical and structural properties of tridimensional materials and their biocompatibility. Murine pre-osteoblasts from 3T3-E1 line were put in contact with the alginate hydrogels enriched with 5% Mg (HGAF50) and with either 5% HA (HGAF50_5), 10% HA (HGAF50_10) or 20% HA (HGAF50_20). Their biocompatibility was tested with MTT, LDH and LiveDead assays. The evaluated composites displayed good biocompatible properties. Significantly increased cell proliferation was found on HGAF50_5, while cell growth was limited on HGAF50_20.
Finally, a similar study concerning ceramic scaffolds based on HA but with different concentrations of Mg (5%, 10%) obtained at a calcination temperature of 800oC or 1000oC was performed. They were seeded with murine pre-osteoblasts (3T3-E1) and their biocompatibility was tested. The HA composite with 5% Mg showed an overall better cell viability and proliferation rate, compared to the neat HA control and the one enriched with 10% Mg, regardless of the calcination temperature.
These results helped to identify proper materials for future differentiation studies in order to potentially develop tissue-like structures for tissue engineering applications.