Authors: E.S. Thian, Jie Huang, Serena Best, Zoe H. Barber, William Bonfield
Abstract: 0.8 wt.% silicon-containing hydroxyapatite (Si-HA) thin films of thickness 600 nm have been successfully developed using a magnetron co-sputtering technique, through careful selection and control of the processing conditions. These films were immersed in simulated body fluid (SBF) to investigate the nucleation and growth of an apatite layer on their surfaces. A newly-formed apatite layer with similar characteristics to that of the biological bone apatite, was observed after 4 days of
immersion in SBF. X-ray diffraction and infrared analyses confirmed this layer to be calciumdeficient micro-crystalline carbonate HA. These results demonstrated that the novel Si-HA films were highly bioactive and the time frame required for apatite formation was reduced by approximately 76 % (from 17 days to 4 days).
445
Authors: Frank A. Müller, Kristina Lessnau, Lenka Müller, Marcus W. Rauch, Cordt Zollfrank, Peter Greil
Abstract: A composite material consisting of cellulose and HAp was prepared using coagulation of a native cellulose suspension. Composite tapes with a HAp content below 50 vol.% exhibit a gradient of filler particles across the cross-section of the sample due to gravity force that causes sedimentation of HAp, as long as the viscosity of the suspension is below a critical level during the coagulation
process. According to gravimetric and solution analysis as well as SEM, the filler content influences the amount and uniformity of HCA precipitated in the surface of the tape. With increasing content of filler in the cellulose matrix, the apatite growth from SBF is promoted, due to a higher amount of HAp particles that serve as nucleation sites.
1173
Authors: Akemi A. Nogiwa-Valdez, Dora A. Cortés-Hernández, J.M. Almanza-Robles, Alejandra Chávez-Valdez
Abstract: Zirconia-alumina composites with additions of a CaO-SiO2 glass are prepared by uniaxial pressing and sintering. In order to promote bioactivity, the composites are biomimetically treated. The effect of immersion time in simulated body fluids (SBF) and that of the presence of a wollastonite powder bed, as a calcium ion provider, on the apatite forming ability are investigated. The influence of replacing the simulated body fluids each 7-day-period for a more concentrated solution is also studied. A bonelike apatite layer is observed after 21 days of immersion when the
SBF is renewed, whether the bed of wollastonite powder is present or not. However, a thicker layer is formed by using wollastonite and the agglomerates of the apatite layer are finer on the composites containing CaO-SiO2 glass.
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Authors: El-Sayed Ghaith, Toshihiro Kasuga, Masayuki Nogami
Abstract: Amorphous calcium silicate coating on a metallic titanium substrate for hard tissue
replacement was prepared by a sol-gel method. Calcium silicate film was deposited on a titanium
substrate by a spin-coating technique and subsequently heated at 500°C for 2 h in air. The deposited
film, which was dense, had thickness of about 800 nm and strongly adhered to the substrate.
Biomimetic apatite-forming ability of the deposited films was examined by soaking in simulated body
fluid (SBF). Thin film X-ray diffractometry and scanning electron microscopy showed the formation
of apatite on the surface after 10 days of soaking in SBF.
235
Authors: Hai Long Yang, Shouichi Somegawa, Ying Jie Yang, Zhi Chen Luo
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