تهيه و مشخصه يابي كامپوزيت زيست فعال آلياژ پايه كبالت با تقويت كننده شيشه زيست فعال نانو متري

چكيده انگليسي :

Preparation and Characterization of Bioactive Co Base Alloy Composite Reinforced with Nanobioactive Glass Raziyeh Gharahkhani r gharahkhani@ma iut ac ir Date of Submission 2011 04 05 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor M H Fathi fathi@cc iut ac ir Supervisor M Ahmadian ahmadian@cc iut ac ir Abstract Cobalt based alloys form on their surface a thin 1 4 nm passive film which consists of a mix of cobalt chromium and molybdenum oxides thus Cobalt based alloys are bioinert and after implantation in body a fibrous texture would be formed around it In this study bioactive composite from cobalt based alloy and nano bioactive glass was synthesized For this purpose metallic alloy powders were mixed with 10 15 and 20 nano bioactive glass Then the mixtures were pressed and sintered via two step sintering method Temperature range at the first step was 900 1100 C and time of this step was 10 min and temperature range at the second step was 700 900 C and time range of this step was 2 14 hours X ray diffraction was done in order to phase analysis Bioactivity of samples was determined via immersion in simulated body fluid after 7 14 21 and 28 days Scanning electron microscopy was used to evaluate surface of samples before and after immersion The pH variations and also Ca P and Si ions concentrations were measured via ICP OES method Bonds that were formed in samples were determined by FTIR method Density of samples was determined via immersion method Cell culture test in order to evaluate bone cells growth and adherence of them on surface of samples and also MTT test for composites biocompatibility determination were done Maximum density of samples including 10 15 and 20 nano bioactive glass were 96 2 0 3 93 9 0 3 and 86 8 0 2 percents of the theoretical density respectively These results were achieved when first step sintering temperature was 1000 C and second step sintering time was 10 hours After sintering no phase changes were observed SEM study revealed agglomeration of nano bioactive glass particles with increasing amount of them in composite In first days of immersion samples in simulated body fluid pH increased and after then decreased This observation was because of reactions in order to precipitation of carbonate hydroxy apatite With increasing reinforcement amount number and dimension of carbonate hydroxy apatite precipitations which were formed on surface of samples were increased Calcium ion measurement revealed by increasing amount of reinforcement quantity calcium ion release increases and composite including 20 reinforcement had highest ability to absorb calcium ion among other composites As time of immersion and also amount of nano bioactive glass increased silicon ion release increased and caused to increase number of apatite nucleation sites It was found that just after one day lapse of cell culture cells bonded to surface and a suitable primary contact with cells and surface had been formed On 7th day of cell culture test bonds between cells were also observed that indicating complete cell adherence to surface MTT test after 7 days immersion revealed synthsised composites were not toxic and they were biocompatible It could be concluded that using nano bioactive glass as reinforcement in cobalt based alloy matrix induces bioactivity and formation a layer of carbonate hydroxy apatite on the composite surface In addition growth and bonding of osteroproducer cells on surface of composite samples indicated biocompatibility of samples Key words Co Based Alloy Nanobioactive Glass Bioactivity Biocompatibility

قره خاني، راضيه

تهيه و مشخصه يابي كامپوزيت زيست فعال آلياژ پايه كبالت با تقويت كننده شيشه زيست فعال نانو متري

نانو ذرات شيشه زيست فعال , زيست سازگاري