Development and mechanical characterization of hydroxyapatite micro/macro-porous scaffolds by an innovative gel-casting process

AbstractAn innovative gel-casting process was developed in order that the micro and macro Obtain porous hydroxyapatite (Ca 10 (PO 4) 6 (OH) 2, HA) scaffolds to be used in regenerative medicine for bone tissue reconstruction. The micro-porous materials were prepared using HAsuspensions having different solid loadings (in the range of 55-60 wt%) and gelling agent contents (in the range of 0.3-0.75 wt%). Afterthem set-up of the operative parameters, macro-porous components were also prepared by using commercial spheres polyethylene (PE), sieved in the range 355-420 m, as a fugitive agent, added to the ceramic suspensions before casting. The EP was xed amount forobtaining a porosity of 60 vol% in the red materials. The mechanical investigation and you will out on both dense and porous samples.The compressive tests, 4-point bending tests and micro-hardness measurements were performed in order is the Young's modulus DETERMINE, compressive strength, ultimate tensile stress and fracture toughness. Good correlations between mechanical properties were found. Theresults Obtained for micro and macro-pororous specimens were related with a model based on the ideal cell. An extensive microstructuralcharacterization and you will be out SEM and coupled this mechanical data in view of the validation of modeling tools based on the DIB-FEA (digital image based nite element analysis) procedures.Keywords: Hydroxyapatite, Micro / macro-porous scaffolds, Mechanical properties, DIB-FEAROZWÓJ MECHANICAL AND MICRO / MACRO-POROUS RUSZTOWAHYDROKSYAPATYTOWYCH RECEIVED SUPPORT INNOVATIVE PROCESS FOR CASTING ELOWEGORozwinito innovative drawn through the gel casting process to produce micro-and macro-porous scaffolds of hydroxyapatite (Ca 10 (PO 4) 6 (OH) 2, HA) for use in regenerative medicine for the reconstruction of bone tissue. Micro-macro porowatemateriay suspensions prepared using HA having differing contents upon a fixed phase (in the range 55-60% by wt.) And factor elujcego (in akresie 0.3-0.75 wt%.). MANDATORY After determining the parameters have been makrporowate components wykorzystaniemkomercyjnych spheres prepared from polyethylene (PE), seeded in the range of 355-420 m as refugees A component, added to the suspensions przedodlewaniem. Ilo PE has been fixed so that the burned materiaach receive wynoszc porosity of 60% vol. The study of mechanical properties were carried out on samples of both gstych and porous. Compression tests were performed, 4-punktowegozginania and microhardness measurements you to mark the Young's modulus, compressive strength, ultimate strength in bending and resistance to cracking. It was a good correlation between views and mechanical properties. The results obtained in the case of micro-and makroporowatychpróbek linked with the model based on cell ideal. Extensive characteristics mikrostrukturalnza SEM assistance in relation to the test results of mechanical properties in order to assess the soundness of tools modelujcych opartychna procedure DIB-FEA (digital image based nite element analysis - digital mapping based on the analysis of elements skoczonych.) Key words: hydroxyapatite, micro / macroporous scaffold mechanical properties, DIB-FEA

Abstract An innovative gel-casting process was developed in order to obtain micro and macro porous hydroxyapatite (Ca10(PO4)6(OH)2, HA) scaffolds to be used in regenerative medicine for bone tissue reconstruction. The micro-porous materials were prepared using HA suspensions having different solid loadings (in the range of 55-60 wt%) and gelling agent contents (in the range of 0.3-0.75 wt%). After the set-up of the operative parameters, macro-porous components were also prepared by using commercial polyethylene spheres (PE), sieved in the range 355-420 m, as a fugitive agent, added to the ceramic suspensions before casting. The PE amount was xed for obtaining a porosity of 60 vol.% in the red materials. The mechanical investigation was carried out on both dense and porous samples. The compressive tests, 4-point bending tests and micro-hardness measurements were performed in order to determine Young’s modulus, compressive strength, ultimate tensile stress and fracture toughness. Good correlations between mechanical properties were found. The results obtained for micro and macro-pororous specimens were related with a model based on the ideal cell. An extensive microstructural characterization was carried out by SEM and coupled to mechanical data in view of the validation of modelling tools based on DIB-FEA (digital image based nite element analysis) procedures. Keywords: Hydroxyapatite, Micro/macro-porous scaffolds, Mechanical properties, DIB-FEA ROZWÓJ I CHARAKTERYSTYKA MECHANICZNA MIKRO/MAKRO-POROWATYCH RUSZTOWA HYDROKSYAPATYTOWYCH OTRZYMANYCH ZA POMOC INNOWACYJNEGO PROCESU ODLEWANIA ELOWEGO Rozwinito innowacyjny proces odlewania elowego w celu otrzymania mikro i makroporowatych rusztowa hydroksyapatytowych (Ca10(PO4)6(OH)2, HA) przeznaczonych do wykorzystania w medycynie regeneracyjnej do rekonstrukcji tkanki kostnej. Mikro-makro porowate materiay przygotowano przy wykorzystaniu zawiesin HA o rónej zawarto ci fazy staej (w zakresie 55-60 % wag.) i czynnika eluj cego (w akresie 0.3-0.75 % wag.). Po ustaleniu obowi zuj cych parametrów, makrporowate komponenty zostay przygotowane z wykorzystaniem komercyjnych kul polietylenowych (PE), wysianych w przedziale 355-420 m, jako uchodz cy skadnik, dodawany do zawiesin przed odlewaniem. Ilo PE zostaa ustalona tak, aby w wypalonych materiaach otrzyma porowato wynosz c of 60 % obj. Badania wa ciwo ci mechanicznych przeprowadzono na próbkach zarówno gstych, jak i porowatych. Przeprowadzono testy ciskania, 4-punktowego zginania i pomiary mikrotwardo ci, aby oznaczy modu Younga, wytrzymao na ciskanie, ostateczn wytrzymao na zginanie i odporno na pkanie. Stwierdzono dobr korelacj pomidzy wa ciwo ciami mechanicznymi. Wyniki uzyskane w przypadku mikro- i makroporowatych próbek powi zano z modelem opartym na komórce idealnej. Przeprowadzono obszern charakterystyk mikrostrukturaln za pomoc SEM w odniesieniu do wyników bada wa ciwo ci mechanicznych w celu oceny poprawno ci narzdzi modeluj cych opartych na procedurze DIB-FEA (digital image based nite element analysis – odwzorowanie cyfrowe oparte na analizie elementów skoczonych). Sowa kluczowe: hydroksyapatyt, mikro/makroporowate rusztowanie, wa ciwo ci mechaniczne, DIB-FEA