توليد و مشخصه يابي فوم كامپوزيتي بيوسراميكي نانو ساختار براي كاربرد در مهندسي بافت

چكيده انگليسي :

Fabrication and Characterization of Nanostructure Bioceramic Composite Foam for Using in Tissue Engineering Hamed Ghomi h ghomi@ma iut ac ir Date of Submission 2011 03 12 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mohammadhossein Fathi fathi@cc iut ac ir Hossein Edris h edris@cc iut ac ir Abstract The new challenge in biomaterials is to enhance the body s own regenerative capacity by stimulating genes that initiate repair at the site of damage or disease Highly porous bioceramic scaffolds foams supply a framework for enhanced cell infiltration and migration throughout the scaffold and act as a template for bone growth Hydroxyapatite HA is characterized by its high biocompatibility and close chemical similarity to biological apatite However its reactivity with existing bone and the rate at which bone apposes and integrates with HA is relatively low BGs are more reactive degradable osteoconductive and show better bioactivity than HA BGs could bond to hard and soft tissue and the degradation products of them could stimulate the production of growth factors cell proliferation and activate the gene expression of osteoblast The limiting factor in the use of BGs is the inherent brittleness of glass If HA and BG are to be combined in an optimized tissue engineering scaffold then the designed composite allows for the creation of bioresorbable and bioactive scaffolds with tailored physical and mechanical properties Considering benefits of nanostructure bioceramics in this study effort was focused on fabrication and characterization of nanostructure bioceramic composite foam For this purpose HA and BG nanopowders were synthesized by the sol gel method and nanocomposite foams were prepared on addition of 63S BG to pure HA in proportion of 0 25 50 75 and 100 wt X ray diffraction XRD Scanning electron microscopy SEM Energy Dispersive Spectroscopy EDS and Transmission electron microscopy TEM were used to characterize and evaluate the phase structure crystallite size morphology size and distribution of the pores chemical composition and particle size of the prepared powders and composite foams The porosity of the foams was measured by Archimedes method The compressive tests were performed on samples consisting of cylindrical bars with a crosshead speed of 0 5 mm min The specific surface area of the prepared powders and composite foams were calculated from the N2 adsorption isotherms using the multipoint Brunauer Emmett Teller BET technique To evaluate the bioactivity and bioresorbability the prepared foams were immersed in the simulated body fluid SBF for 28 days The concentration of the calcium and phosphorous ions in the filtered solutions were determined by inductive coupled plasma optical emission spectroscopy ICP OES Fourier transform infrared spectroscopy FTIR XRD and SEM were used to investigate the bone like apatite formation on the surface of the foams and pores filling by formation of apatite The results showed that the foams have a grain size smaller than 50 nm and pore size in the range 100 400 m The compressive strength and elastic modulus increased with increasing amount of BG addition up to 25 wt and then decreased by more addition of BG The maximum values of compressive strength and elastic modulus were found to be about 2 78 MPa and 219 MPa respectively which are close to the lower limit of the compressive strength and elastic modulus of cancellous bone The mean values of true and apparent porosity were calculated in the range 88 84 and 57 76 respectively In vitro tests showed high bioactivity and resorbability of the foams The resulting foams have similar chemical composition to the mineral phase of bone and by changing the ratio of HA BG can reach the appropriate bioactivity and biodegradability level needed for different applications Considering the results obtained it seems that manufactured foams could be a good candidate for tiss

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توليد و مشخصه يابي فوم كامپوزيتي بيوسراميكي نانو ساختار براي كاربرد در مهندسي بافت

شيشه زيست فعال , هيدروكسي آپاتيت , قالب ريزي ژل , نانو كامپوزيت , تخلخل , خواص مكانيكي , كاربرد پزشكي