Design and Production Engineering&Mechatronics, Automation and Smart Materials

Biography

Biography: Maria Giulia Faga

Abstract

Ceramic materials are widespread employed in biomedical application thanks to high strength and wear resistance. Among them, tetragonal ZrO₂ shows bioactivity properties, although phase transition towards the monoclinic phase makes it unsuitable for biomedical applications. The problem has been solved by using ZrO₂-Al₂O₃ composites, for which limited or absent phase transition is observed. However, similar biomaterials still present mechanical properties far to those of hard tissues. A possible strategy to overcome this issue is represented by the dispersion of alumina-zirconia composites in a polymer matrix. In such way it could be possible to obtain an implant easy to be processed, inexpensive, with suitable mechanical properties and good cells interaction. Polymer composites have also the advantage of a contrast adjustable radio-transparency and are compatible with modern diagnostic methods. In this work, different amounts of Alumina Toughened Zirconia (80–20 wt %) (ATZ) have been added to Ultra High Molecular Weight Polyethylene (UHMWPE). The UHMWPE/ATZ composites were prepared by solid state mixing, using a homogenizer, followed by compression molding. The structural, morphological, thermal, mechanical characterization and cells interaction of ATZ-UHMWPE are reported for the first time in order to assess the feasibility of these materials for biomedical tissue reconstruction.

In PE2.5 composite, ATZ particles are uniformly distributed along the ‘‘grain’’ boundaries, whereas at higher concentrations (10 and 20 wt %) they form micrometric agglomerates. The PE2.5 composite has improved elastic modulus and yield stress respect to bare UHMWPE. For all the other composites, an increase in the elastic modulus respect to neat UHMWPE is observed, although the other mechanical parameters are reduced by increasing ATZ content. The results can be explained in terms of poor dispersion of the oxide in the polymer matrix at concentrations higher than 2.5 wt %. Furthermore, the good dispersion of ATZ seems to positively affect the cells adhesion and protein adsorption (using Bovine Serum Albumin, BSA).