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Micro-poro-elasticity of baghdadite scaffolds:a unifying approach based on ultrasonics, nanoindentation, and homogenization theory

Bone tissue engineering aims at repairing damaged bone and restoring its functions with the help of biocompatible materials cultivated with cells and corresponding growth factors. Besides being osteoconductive and osteoinductive , the bone substitute or scaffold should be able to carry sufficient load and exhibit appropriate mechanical properties. Highly porous baghdadite (Ca3ZrSi2O9) scaffolds have shown promising biological responses when used for the repair of critical size defects in rabbit radial bones. Nevertheless, mechanical properties of these scaffolds require further investigation. Therefore, by using structure-property relations derived from experiments, and on the basis of theoretical and applied micromechanics, the current research aims at applying the state-of-the-art methods in computational biomechanics and biomaterials to this new material, particularly, to investigate its elastic properties.The analysis started with ultrasonic measurements which yielded the normal stiffness C_11, which was used in a poro-micromechanics model that has been validated across a wide variety of different porous polycrystals. The Young’s modulus and Poisson’s ratio were obtained through the model. These estimates were impressively confirmed by a physically and statistically independent nanoindentation campaign comprising some 1750 indents by means of statistical de-convolution following, the elastic intact dense ceramic phase from pore phases, or ceramic being damaged during the indentation process.

Author(s):

Hawraa Kariem    
Vienna University of Technology, Institute for Mechanics of Materials and Structures
Austria

Maria-Ioana Pastrama    
Vienna University of Technology, Institute for Mechanics of Materials and Structures
Austria

Seyed-Iman Roohani-Esfahani    
University of Sydney, Biomaterials and Tissue Engineering Research Unit
Australia

Peter Pivonka    
University of Melbourne, Australian Institute for Musculoskeletal Science
Australia

Hala Zreiqat    
University of Sydney, Biomaterials and Tissue Engineering Research Uni
Australia

Christian Hellmich    
Vienna University of Technology, Institute for Mechanics of Materials and Structures
Austria