ΘΕΜΑ: Παρουσίαση Διδακτορικού Χατζηχαραλάμπους Χρυσταλλένης ΑΠΟΣΤΟΛΕΑΣ: Charalampos Stratigis [mailto:stratigis@xxxxxxxxxxxxxxxx]
Πρόσκληση σε Δημόσια Παρουσίαση της Διδακτορικής Διατριβής της κ. Χατζηχαραλάμπους Χρυσταλλένης (Σύμφωνα με το άρθρο 12 του Ν. 2083/92) Την Πέμπτη 18 Ιουνίου 2015 και ώρα 10:00 στην αίθουσα A210 στο κτίριο του Τμήματος Μαθηματικών θα γίνει η δημόσια παρουσίαση και υποστήριξη της Διδακτορικής Διατριβής της υποψήφιας διδάκτορα του Τμήματος Επιστήμης και Τεχνολογίας Υλικών κ. Χατζηχαραλάμπους Χρυσταλλένης με θέμα: “Κυτταρική απόκριση προ-οστεοβλαστών σε πορώδη κεραμικά υλικά και νανοσωματίδια για αναγέννηση οστού” “Pre-osteoblastic Cell Response on Porous Ceramic Biomaterials and Nanoparticles for Bone Regeneration” ABSTRACT Due to critical bone defects, arising from trauma, tumour resection or bone diseases, appropriate strategies to replace or regenerate bone have become a major clinical challenge. In this thesis, we investigate porous alumina and zirconia scaffolds for bone repair, as well as calcium phosphate nanoparticles for bone morphogenetic protein (BMP) gene delivery, as part of a strategy to heal large bone defects. In the first part, we show that cellular response to alumina and zirconia, in terms of cell adhesion, viability, proliferation, and osteogenic differentiation are highly affected by material porosity and chemical composition. Such studies are crucial for the development of implantable ceramic biomaterials that integrate with bone tissue. Notably, we achieved improved adhesion and proliferation of pre-osteoblasts by increasing substrate porosity in zirconia ceramics. Chemical modifications within porous zirconia including their stabilization by either yttria or magnesia, affect pre-osteoblastic cell attachment, changing cell morphology, proliferation, and gene _expression_ of osteogenic markers. In the second part, we show that calcium phosphate nanoparticles loaded with plasmid human DNA encoding for Bone Morphogenetic Protein 7 (phBMP-7), are a promising gene delivery system for pre-osteoblasts. The nanoparticles show high transfection efficiency together with low cytotoxicity. Following transfection, hBMP-7 is synthesized and secreted in the cell culture. As a result, increased levels of the osteogenic marker alkaline phosphatase as well as calcium mineralization are detected in cell cultures. The cell transfection is shown to be transient, which is essential for temporary gene _expression_. We conclude that porous zirconia ceramics may be useful as non-degradable scaffolds that support cell growth in large bone defects. The calcium phosphate nanoparticles loaded with phBMP-7 represent a promising tool for therapeutic approaches in bone regeneration. |