Acceleration of Apatite Nucleation on Parallel Aligned Ti-Substrates with Optimum Gaps by UV-Light Pre-Irradiation


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A recently developed “GRAPE® technology” provides titanium or titanium alloy implants with spontaneous apatite-forming ability in vitro, which requires properly designed gaps and optimum heat treatment in air. In this study, pure titanium pieces were thermally oxidized in air and pre-irradiated by UV-light under different environmental conditions such as in air or in ultra-pure water before aligning pairs of specimens in the GRAPE® set-up, i.e., two pieces of titanium substrates were aligned parallel to each other with optimum gap width (spatial design). Then, they were soaked in Kokubo’s simulated body fluid (SBF, pH7.4, 36.5°C) for 1-2 days to clarify how the UV-light pre-irradiation affects the in vitro apatite nucleation on the substrates under the specific spatial design. UV-light pre-irradiation in water led to the deposition of a large number of apatite particles within 1 day, and showed apatite X-ray diffraction, although UV-light pre-irradiation in air and non-pretreated specimens gave the deposition of a few apatite particles and did not show any apatite X-ray diffraction. These results indicated that the rate of primary heterogeneous nucleation of apatite increased by UV-light pre-irradiation in ultra-pure water. TF-XRD patterns of the surface of the substrates thermally oxidized in air at 500°C showed the peak at 2θ = 27º assignable to the 110 diffraction of rutile phase of titanium dioxide (ICDD-JCPDS data #21-1276). Previous studies reported that the primary heterogeneous nucleation must be induced by Ti-OH groups on titanium oxide layer. Probably, the UV-light pre-irradiation in ultra-pure water can increase the number of Ti-OH groups on the surface, resulting in accelerated primary heterogeneous nucleation of apatite.



Key Engineering Materials (Volumes 493-494)

Main Theme:

Edited by:

Eyup Sabri Kayali, Gültekin Göller and Ipek Akin




S. Hayakawa et al., "Acceleration of Apatite Nucleation on Parallel Aligned Ti-Substrates with Optimum Gaps by UV-Light Pre-Irradiation", Key Engineering Materials, Vols. 493-494, pp. 936-939, 2012

Online since:

October 2011




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