Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups.
The surfaces of ethylene-vinyl alcohol copolymer (EVOH) substrates were modified with silanol (Si-OH) groups, and their apatite forming ability was examined in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma or in a solution with ion concentrations 1.5 times those of SBF (1.5SBF). The surface modification of EVOH was carried out by reacting 3-isocyanatopropyltriethoxysilane, followed by hydrolysis of the ethoxysilyl groups into Si-OH groups. However, no apatite formation was observed on the EVOH substrate thus modified, even after 3 weeks in SBF and 1.5SBF. The Si-OH modified EVOH substrate was further modified by hydrolysis and polycondensation of tetraethyoxysilane (TEOS). It was found that the apatite forms on the TEOS-modified substrate within 3 weeks in 1.5SBF. These results suggest that the presence of a large amount of Si-OH groups (i.e., a cluster of Si-OH groups) on the substrate is prerequisite to apatite formation in the body environment. Apatite-EVOH composites prepared by this process might be useful as hard tissues substitutes.
Oyane
A
A
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-Ku, Kyoto, 606-8506, Japan. ohyane@sung7.kuic.kyoto-u.ac.jp
Minoda
M
M
Miyamoto
T
T
Takahashi
R
R
Nakanishi
K
K
Kim
H M
HM
Kokubo
T
T
Nakamura
T
T
D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D001826:Body Fluids; D004573:Electrolytes / Q000097:blood / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000097:blood; D008855:Microscopy, Electron, Scanning; D011145:Polyvinyls / Q000737:chemistry*; D012821:Silanes; D013499:Surface Properties
D001031:Apatites; D001672:Biocompatible Materials; D004573:Electrolytes; D011145:Polyvinyls; D012821:Silanes; C020320:ethylene-vinyl alcohol copolymer; D007501:Iron