TY - JOUR
T1 - Initial formation kinetics of calcium phosphate on titanium in Hanks' solution characterized using XPS
AU - Hiji, Akari
AU - Hanawa, Takao
AU - Shimabukuro, Masaya
AU - Chen, Peng
AU - Ashida, Maki
AU - Ishikawa, Kunio
N1 - Funding Information:
Ministry of Education, Culture, Sports, Science and Technology; JSPS KAKENHI, Grant/Award Number: 16K15798 Funding information
Funding Information:
This work was supported by JSPS KAKENHI Grant Number 16K15798 and by the Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development Project and Biable Materials Project, Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
© 2020 John Wiley & Sons, Ltd.
PY - 2021/2
Y1 - 2021/2
N2 - One cause of the excellent hard-tissue compatibility of Ti and Ti alloys compared with other metals is their ability to form calcium phosphate in biological environments. This is confirmed by many studies, although the formation mechanism has not been completely elucidated. In this study, to elucidate the initial formation kinetics of calcium phosphate on Ti in the human body, Ti was immersed in a simulated body fluid, Hanks' solution, for 100–106 s, followed by precise characterization using XPS. Ti specimens immersed in diluted Hanks' solutions were also characterized. The results reveal that phosphate ions are preferentially adsorbed and are incorporated onto the Ti surface in 100–102 s. This reaction is slow, and the apparent thickness of the surface layer is almost constant as 5.2 nm until 102 s. However, both calcium and phosphate ions are then rapidly incorporated, and calcium phosphate is formed after 103 s. The amounts of both calcium and phosphate increase with the logarithm of time because calcium and phosphate ions react directly with the Ti surface until 105 s. Other elements contained in Hanks' solution are not incorporated, calcium phosphate being formed preferentially. The incorporation of calcium is faster than that of phosphate, and the [Ca]/[P] ratio increases with the logarithm of time after 103 s. However, the chemical state of surface oxide film itself on Ti does not changed by immersion in Hanks' solution. The formation kinetics of calcium phosphate on Ti in a simulated body fluid are clearly revealed by this study.
AB - One cause of the excellent hard-tissue compatibility of Ti and Ti alloys compared with other metals is their ability to form calcium phosphate in biological environments. This is confirmed by many studies, although the formation mechanism has not been completely elucidated. In this study, to elucidate the initial formation kinetics of calcium phosphate on Ti in the human body, Ti was immersed in a simulated body fluid, Hanks' solution, for 100–106 s, followed by precise characterization using XPS. Ti specimens immersed in diluted Hanks' solutions were also characterized. The results reveal that phosphate ions are preferentially adsorbed and are incorporated onto the Ti surface in 100–102 s. This reaction is slow, and the apparent thickness of the surface layer is almost constant as 5.2 nm until 102 s. However, both calcium and phosphate ions are then rapidly incorporated, and calcium phosphate is formed after 103 s. The amounts of both calcium and phosphate increase with the logarithm of time because calcium and phosphate ions react directly with the Ti surface until 105 s. Other elements contained in Hanks' solution are not incorporated, calcium phosphate being formed preferentially. The incorporation of calcium is faster than that of phosphate, and the [Ca]/[P] ratio increases with the logarithm of time after 103 s. However, the chemical state of surface oxide film itself on Ti does not changed by immersion in Hanks' solution. The formation kinetics of calcium phosphate on Ti in a simulated body fluid are clearly revealed by this study.
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U2 - 10.1002/sia.6900
DO - 10.1002/sia.6900
M3 - Article
AN - SCOPUS:85093513072
VL - 53
SP - 185
EP - 193
JO - Surface and Interface Analysis
JF - Surface and Interface Analysis
SN - 0142-2421
IS - 2
ER -