Towards computer-aided design of bio-materials; by example of micro-elasticity of porous ceramic baghdadite

Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheMicrostructure-elasticity relations for bone tissue engineering scaolds are key to rationally based biomaterial design. As a contribution, we here report comprehensive length measuring, weighing, and ultrasonic tests at 0.1 MHz frequency, on porous baghdadite scaolds. The resulting porosity-stiness relations further con rm a formerly detected, micromechanically explained, general relationship for a great variety of different polycrystals (Fritsch et al., 2013), which also allows for estimating the zero-porosity case, i.e. the Young's modulus and Poisson's ratio of pure (dense) baghdadite. These estimates were impressively con rmed by a physically and statistically independent nanoindentation campaign comprising some 1750 indents. Consequently, we can present a remarkably complete picture of porous baghdadite elasticity across a wide range of porosities, and, thanks to the micromechanical understanding, reaching out beyond classical elasticity, towards poroelastic properties, quantifying the eect of pore pressure on the material system behaviour.Microstructure-elasticity relations for bone tissue engineering scaolds are key to rationally based biomaterial design. As a contribution, we here report comprehensive length measuring, weighing, and ultrasonic tests at 0.1 MHz frequency, on porous baghdadite scaolds. The resulting porosity-stiness relations further con rm a formerly detected, micromechanically explained, general relationship for a great variety of different polycrystals (Fritsch et al., 2013), which also allows for estimating the zero-porosity case, i.e. the Young's modulus and Poisson's ratio of pure (dense) baghdadite. These estimates were impressively con rmed by a physically and statistically independent nanoindentation campaign comprising some 1750 indents. Consequently, we can present a remarkably complete picture of porous baghdadite elasticity across a wide range of porosities, and, thanks to the micromechanical understanding, reaching out beyond classical elasticity, towards poroelastic properties, quantifying the eect of pore pressure on the material system behaviour.4

Micro-CT-based identification of double porosity in fired clay ceramics

Optimizing thermal and mechanical properties of clay block masonry requires detailed knowledge on the microstructure of fired clays. We here identify the macro- and microporosity stemming from the use of three different pore-forming agents (expanded polystyrene, sawdust, and paper sludge) in different concentrations. Micro-CT measurements provided access to volume, shape, and orientation of macropores, and in combination with X-ray attenuation averaging and statistical analysis, also to voxel-specific microporosities. Finally, the sum of micro- and macroporosity was compared to corresponding data gained from two statistically and physically independent methods (namely from chemical analysis in combination with weighing, and from mercury intrusion porosimetry). Satisfactory agreement of all these independently gained experimental data renders our new concept for identifying the pore spaces of fired clay as a very promising tool supporting the further optimization of clay blocks.Österreichische Forschungsförderungsgesellschaft (FFG

A new Nanoindentation Protocol for identifying the elasticity of undamaged extracellular bone tissue

\u3cp\u3eWhile the quest for understanding and even mimicking biological tissue has propelled, over the last decades, more and more experimental activities at the micro and nanoscales, the appropriate evaluation and interpretation of respective test results has remained a formidable challenge. As a contribution to tackling this challenge, we here describe a new method for identifying, from nanoindentation, the elasticity of the undamaged extracellular bone matrix. The underlying premise is that the tested bovine bone sample is either initially damaged (i.e. exhibits micro-cracks a priori) or that such micro-cracks are actually induced by the nanoindentation process itself, or both. Then, (very many) indentations may relate to either an intact material phase (which is located sufficiently far away from micro-cracks), or to differently strongly damaged material phases. Corresponding elastic phase properties are identified from the statistical evaluation of the measured indentation moduli, through representation of their histogram as a weighted sum of Gaussian distribution functions. The resulting undamaged elastic modulus of bovine femoral extracellular bone matrix amounts to 31 GPa, a value agreeing strikingly well both with direct quasi-static modulus tests performed on SEM-FIB-produced micro-pillars (Luczynski et al., 2015), and with the predictions of a widely validated micromechanics model (Morin and Hellmich, 2014). Further confidence is gained through observing typical indentation imprints under Scanning Electron Microscopy (SEM), which actually confirms the existence of the two types of micro-cracks as described above.\u3c/p\u3

Micro-poro-elasticity of baghdadite-based bone tissue engineering scaffolds:A unifying approach based on ultrasonics, nanoindentation, and homogenization theory

\u3cp\u3eMicrostructure-elasticity relations for bone tissue engineering scaffolds are key to rational biomaterial design. As a contribution thereto, we here report comprehensive length measuring, weighing, and ultrasonic tests at 0.1 MHz frequency, on porous baghdadite (Ca\u3csub\u3e3\u3c/sub\u3eZrSi\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e9\u3c/sub\u3e) scaffolds. The resulting porosity-stiffness relations further confirm a formerly detected, micromechanically explained, general relationship for a great variety of different polycrystals, which also allows for estimating the zero-porosity case, i.e. Young modulus and Poisson ratio of pure (dense) baghdadite. These estimates were impressively confirmed by a physically and statistically independent nanoindentation campaign comprising some 1750 indents. Consequently, we can present a remarkably complete picture of porous baghdadite elasticity across a wide range of porosities, and, thanks to the micromechanical understanding, reaching out beyond classical elasticity, towards poroelastic properties, quantifying the effect of pore pressure on the material system behavior.\u3c/p\u3

Micro-poro-elasticity of baghdadite-based bone tissue engineering scaffolds: A unifying approach based on ultrasonics, nanoindentation, and homogenization theory

Microstructure-elasticity relations for bone tissue engineering scaffolds are key to rational biomaterial design. As a contribution thereto, we here report comprehensive length measuring, weighing, and ultrasonic tests at 0.1 MHz frequency, on porous baghdadite (Ca3ZrSi2O9) scaffolds. The resulting porosity-stiffness relations further confirm a formerly detected, micromechanically explained, general relationship for a great variety of different polycrystals, which also allows for estimating the zero-porosity case, i.e. Young modulus and Poisson ratio of pure (dense) baghdadite. These estimates were impressively confirmed by a physically and statistically independent nanoindentation campaign. comprising some 1750 indents. Consequently, we can present a remarkably complete picture of porous baghdadite elasticity across a wide range of porosities, and, thanks to the micromechanical understanding, reaching out beyond classical elasticity, towards poroelastic properties, quantifying the effect of pore pressure on the material system behavior. (C) 2014 The Authors. Published by Elsevier B.V

Micro-elasticity of porous ceramic baghdadite : A combined acoustic-nanoindentation approach supported by 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 [1]. Besides being osteoconductive and osteoinductive, the bone substitute or scaffold should exhibit sufficient porosity for good vascular and tissue ingrowth, while not overly compromising the overall mechanical properties of the implant, i.e. its stiffness and strength. The design process of such scaffolds requires a multitude of in vitro and in vivo experiments and has proven to be a challenging task, thus giving rise to the wish for rational, computer-aided design of biomaterials, regarding not only biological and cell transport aspects, but also mechanics. Highly porous baghdadite (Ca3ZrSi2O9) scaffolds have shown promising biological responses when used for the repair of critical size defects in rabbit radial bones [2]. However, the mechanical properties of these scaffolds require further investigation. Therefore, by using structure-property relations derived from ultrasound and nanoindentation 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 to investigate its elastic properties

Micro-poro-elasticity of baghdadite-based bone tissue engineering scaffolds: A unifying approach based on ultrasonics, nanoindentation, and homogenization theory

Microstructure-elasticity relations for bone tissue engineering scaffolds are key to rational biomaterial design. As a contribution thereto, we here report comprehensive length measuring, weighing, and ultrasonic tests at 0.1 MHz frequency, on porous baghdadite (Ca3ZrSi2O9) scaffolds. The resulting porosity-stiffness relations further confirm a formerly detected, micromechanically explained, general relationship for a great variety of different polycrystals, which also allows for estimating the zero-porosity case, i.e. Young modulus and Poisson ratio of pure (dense) baghdadite. These estimates were impressively confirmed by a physically and statistically independent nanoindentation campaign. comprising some 1750 indents. Consequently, we can present a remarkably complete picture of porous baghdadite elasticity across a wide range of porosities, and, thanks to the micromechanical understanding, reaching out beyond classical elasticity, towards poroelastic properties, quantifying the effect of pore pressure on the material system behavior. (C) 2014 The Authors. Published by Elsevier B.V