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Detailed Program
Paper Number : BI-O08
Time Frame : 15:49~16:01
Presentation Date : Thurse day, 27, November
Session Name : Biomaterials
Session Chair 1# : H. S. Yoon
Session Chair 2# : K. Uetsuki
The influence of calcium chloride (CaCl2) concentration on apatite precipitation of surface-modified cobalt-chromium (Co-Cr) alloys in a simulated body fluid
Chao LIU
Kyushu Institute of Technology
Although there has been an increasingly preferred use of Co-Cr alloys as biomaterials in a variety of biomedical applications such as dentistry, cardiovascular devices and orthopedics, they are poor in bone-bonding ability, i.e. bioactivity [1]. In this research, the bioactivity behavior was investigated through surface chemical modification method by immobilizing cross-linked ¥ã-polyglutamic acid onto Co-Cr alloy by changing the concentration of calcium chloride (CaCl2) pre-treatment before soaking in a simulated body fluid [2]. After soaking in SBF for 4 days, the alloy specimens were characterized by thin-film X-ray diffraction (TF-XRD) and scanning electron microscopy (SEM).

Fig 1. TF-XRD patterns of the surfaces of Co-Cr alloy with different concentration of CaCl2 after soaking in SBF for 4 days.
Figure 1 shows TF-XRD patterns of the Co-Cr alloys with different concentration of CaCl2 pre-treatment after soaking in SBF for 4 days. When the Co-Cr alloys were pre-treated with concentration of 0.5 M and 1 M CaCl2 solution, obvious broad peaks at 26¡Æ and 32¡Æ in 2¥è were detected in the diffraction patterns which indicated the apatite were formed on the alloys¡¯ surface. However these peaks were not detected from the alloys with treatment of concentration of 0.01 M and 0.1 M CaCl2 solutions. On the other hand, in contrast with low concentration of CaCl2 solution, after pre-treatment with concentration of 0.5 M and 1 M CaCl2 solution, the apatite layer with spherical particles covered were observed on the surfaces from the SEM photographs. The results of this study show that the apatite formation on Co-Cr alloy in SBF could be successfully induced by chemical surface modification with an appropriate concentration of CaCl2 solution, which would lead to the improvement of bioactivity behavior.
References:
[1] R. Bhure, A. Mahapatro, C. Bonner, T.M. Abdel-Fattah, Materials Science and Engineering C(2013)33:2050-2058.
[2] T. Miyazaki, A. Kuramoto, A. Hirakawa, et al. Dental Materials Journal(2013)32: 544–549.
Acknowledgements :