Development of Co-Sr carbonated hydroxyapatite for biomedical applications
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Date
2017-07
Authors
Muhammad Syazwan Bin Mohd Noor
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Abstract
Cobalt-strontium Carbonated Hydroxyapatite (Co-Sr CHA) was synthesized via
nanoemulsion method. Cobalt (Co) and Strontium (Sr) ions were introduced into the
apatite structure in order to improve their mechanical properties and enhance the
biological activity which closely mimics to the bone mineral. CHA powders were used as
a reference for Co-Sr CHA powders as a comparison in this study. The suitable synthesis
temperature to produce nano-size powders in this study was at room temperature (RT).
Four different compositions of Co-Sr CHA powders were synthesized using same
technique. Among the as-synthesized powders, Co-Sr CHA 1 and Co-Sr CHA 2 were
chosen as optimum composition and used for fabrication of dense products. Sintering was
then performed on the dense samples of Co-Sr CHA at sintering temperature 900˚C and
it cooled down with a dry CO2 atmosphere at temperature 200˚C. All the sintered samples
of Co-Sr CHA were found to retain as B-type CHA. The use of dry CO2 atmosphere was
found can compensate the carbonate loss during sintering at high temperature. The
relative density and diametral tensile strength (DTS) values obtained for Co-Sr CHA 1
were 89.15% and 7.67 MPa respectively and it showed that Co-Sr CHA 1 has better
mechanical properties if compared to sintered samples of CHA and Co-Sr CHA 2. For
bioactivity test, the formation of apatite layer occurred on the surface of sintered samples
of multi-doped CHA after soaking in SBF solution for 7 days. Co-Sr CHA 1 showed good
bioactivity by the fastest formation of apatite layer if compared to other sintered samples.
The amount of cobalt and strontium in the apatite structure were influenced the
mechanical and bioactivity of the products. Thus, substitutions of cobalt and strontium in
the structure successfully enhanced the properties of CHA-based material.