Professor, INSTM Politecnico di Milano, Italy

Maria Cristina Tanzi obtained a Master Degree in Chemistry and Pharmaceutics with honors in 1975 and a Specialization Degree in Experimental Pharmacology in 1979 at Milano University. She was Full Professor of Industrial Bioengineering at the Bioengineering Department, and then at the Chemistry, Materials and Chemical Engineering Department of Politecnico di Milano until March 1st, 2014 when she retired. She was Director of the Laboratory of Biomaterials and co-Director of the Laboratory of Biocompatibility and Cell Culture at Politecnico di Milano. In May 2008, she was nominated member of The International College of Fellows of Biomaterials Science and Engineering. Her research interests comprise synthesis and characterization of polymer biomaterials; design and characterization of polymeric and composite scaffolds for tissue engineering; surface modification to improve cytocompatibility, antibacterial activity and tissue integration.

She is Author and Co-Author of more than 250 scientific papers and 21 Patents on monomers and polymers for environmental, pharmaceutical and biomedical application.

Speech Title: Biomimetic composites based on polyurethane matrices for Bone Tissue Engineering

Aims: Composite materials for Bone Tissue Engineering (BTE) combine the suitability of polymers for the fabrication of 3D porous structures, with the mechanical strength and osteoconductive properties of phosphate ceramics. We explored the preparation of polyurethane (PU)-based composites with micro- and nano- sized hydroxyapatite (HA) fillers, and comparatively investigated their properties and potential use as scaffold for BTE.

Methods: Porous PU composites were produced with a co-expansion process in the presence of micro- or nano-sized HA, using water as expanding agent. PU matrices were also interpenetrated with β-TCP using a vacuum-assisted procedure; bio- mineralization was tested by activation of PU surface via a chemical reaction between Ca and P ions followed or not by immersion in Simulated Body Fluid (SBF). Scaffolds were investigated for morphology, chemico-physical and mechanical properties, and in vitro interaction with osteoblast-like and mesenchymal stem cells.

Results: The addition of micro- or nano-sized HA increased the material density, in comparison with the PU matrix (p>0.05), however not affecting the expansion process and porosity of the scaffolds. Biomineralization of the PU foams, led to a significant increase of mechanical properties and provided a more suitable surface for rat Bone Marrow Mesenchymal Stem Cells attachment and proliferation.

Conclusions: With the proposed co-expansion method composites with morphological and mechanical properties adequate for bone regeneration were obtained. The nucleation of nano-HA onto the surface of the PU foam walls appeared adequate for improving cells adhesion, significantly increasing the compressive mechanical properties of the scaffold.