|
|
Manufacturing of calcium phosphates and silica based scaffolds for bioapllications
Virágová, Eliška ; Hadraba, Hynek (referee) ; Částková, Klára (advisor)
The aim of this diploma thesis was to prepare porous bioceramic scaffolds based on calcium phosphates and calcium phosphates doped with silica. Scaffolds are intended to be used in bone tissue engineering. Two main preparation methods were used for the creation of scaffolds – replica method and direct foaming method. Theoretical part of the diploma thesis is focused on a general description of the skeletal system, biomaterials and methods of preparation of highly porous calcium phosphate ceramics. Experimental part contains a description and the results of prepared scaffolds by above mentioned methods. The preparation process by the direct foaming method was optimized to obtain a defined structure. Calcium phosphate scaffolds containing 0–20 wt.% SiO2 were sintered and studied in terms of material characteristics (phase composition, pore size and porosity, microstructural study by scanning electron microscopy (SEM)), bioactive properties (simulated body fluid (SBF) interaction tests and tests of simulated degradation) and mechanical properties in order to evaluate the effect of silica doping. Scaffolds prepared by both methods were composed of a mixture of hydroxyapatite and/or tricalcium phosphate and cristobalite and wollastonite with comparable porosity in the range of 80–88 %. The pore size of the scaffolds prepared by the direct foaming method reached the interval of 5–250 µm opposite to template method reached the pore size up to 430 µm. The SBF interaction tests and tests of the simulated degradation confirmed the bioactive behavior of the prepared scaffolds and their ability to degrade under the simulated conditions. The scaffolds prepared by the direct foaming method showed better mechanical properties (compressive strength up to 1,8 MPa) than the scaffolds prepared by the template method. The results showed that the prepared scaffolds are suitable and promising for potential applications in bone tissue engineering.
|
|
|
Study of bioceramic composite based on hydroxyapatite and bioglass
Virágová, Eliška ; Hadraba, Hynek (referee) ; Drdlík, Daniel (advisor)
This bachelor thesis is focused on the bioceramic composite materials based on hydroxyapatite (HAp) and bioglass (BG). The wet shaping method, i.e. electrophoretic deposition (EPD), was chosen for the preparation of these materials. The methodology of preparation and its influence on kinetics, relative density and pore distribution in the prepared composites was evaluated. The sintering process of the prepared composites was studied using high temperature dilatometry with subsequent evaluation of their microstructural and mechanical features. It was found that EPD is an applicable method for successful preparation of the particle composites. The microstructural quality of particle composites was affected mainly by the electrical conductivity of the suspension. It was found during the study of EPD kinetics that the highest deposition rate was achieved in the suspension with the lowest electrical conductivity. Increasing amount of BG in HAp caused increase of the relative density and pore diameter whereas the volume of pores decreased. High temperature dilatometry showed a decrease of relative shrinkage, which was evident with increasing HAp amount in the structure. Observation of the microstructure revealed a crystalline structure of BG and an open porosity of HAp, which is desired for biocompatible materials. The phase composition of the materials was determined by X-ray diffraction analysis. In case of the mechanical properties it was found an increase of the hardness and Young’s modulus of elasticity with the increasing amount of BG in bioceramic composites. Based on the obtained results the suitable process and material composition for the planned preparation of the functionally graded material were identified.
|
|
|
Manufacturing of calcium phosphates and silica based scaffolds for bioapllications
Virágová, Eliška ; Hadraba, Hynek (referee) ; Částková, Klára (advisor)
The aim of this diploma thesis was to prepare porous bioceramic scaffolds based on calcium phosphates and calcium phosphates doped with silica. Scaffolds are intended to be used in bone tissue engineering. Two main preparation methods were used for the creation of scaffolds – replica method and direct foaming method. Theoretical part of the diploma thesis is focused on a general description of the skeletal system, biomaterials and methods of preparation of highly porous calcium phosphate ceramics. Experimental part contains a description and the results of prepared scaffolds by above mentioned methods. The preparation process by the direct foaming method was optimized to obtain a defined structure. Calcium phosphate scaffolds containing 0–20 wt.% SiO2 were sintered and studied in terms of material characteristics (phase composition, pore size and porosity, microstructural study by scanning electron microscopy (SEM)), bioactive properties (simulated body fluid (SBF) interaction tests and tests of simulated degradation) and mechanical properties in order to evaluate the effect of silica doping. Scaffolds prepared by both methods were composed of a mixture of hydroxyapatite and/or tricalcium phosphate and cristobalite and wollastonite with comparable porosity in the range of 80–88 %. The pore size of the scaffolds prepared by the direct foaming method reached the interval of 5–250 µm opposite to template method reached the pore size up to 430 µm. The SBF interaction tests and tests of the simulated degradation confirmed the bioactive behavior of the prepared scaffolds and their ability to degrade under the simulated conditions. The scaffolds prepared by the direct foaming method showed better mechanical properties (compressive strength up to 1,8 MPa) than the scaffolds prepared by the template method. The results showed that the prepared scaffolds are suitable and promising for potential applications in bone tissue engineering.
|
|
|
Study of bioceramic composite based on hydroxyapatite and bioglass
Virágová, Eliška ; Hadraba, Hynek (referee) ; Drdlík, Daniel (advisor)
This bachelor thesis is focused on the bioceramic composite materials based on hydroxyapatite (HAp) and bioglass (BG). The wet shaping method, i.e. electrophoretic deposition (EPD), was chosen for the preparation of these materials. The methodology of preparation and its influence on kinetics, relative density and pore distribution in the prepared composites was evaluated. The sintering process of the prepared composites was studied using high temperature dilatometry with subsequent evaluation of their microstructural and mechanical features. It was found that EPD is an applicable method for successful preparation of the particle composites. The microstructural quality of particle composites was affected mainly by the electrical conductivity of the suspension. It was found during the study of EPD kinetics that the highest deposition rate was achieved in the suspension with the lowest electrical conductivity. Increasing amount of BG in HAp caused increase of the relative density and pore diameter whereas the volume of pores decreased. High temperature dilatometry showed a decrease of relative shrinkage, which was evident with increasing HAp amount in the structure. Observation of the microstructure revealed a crystalline structure of BG and an open porosity of HAp, which is desired for biocompatible materials. The phase composition of the materials was determined by X-ray diffraction analysis. In case of the mechanical properties it was found an increase of the hardness and Young’s modulus of elasticity with the increasing amount of BG in bioceramic composites. Based on the obtained results the suitable process and material composition for the planned preparation of the functionally graded material were identified.
|
guest ::
RSS feed.