Mechanism of Apatite Formation on Bioactive Titanium Metal

1999 ◽  
Vol 599 ◽  
Author(s):  
T. Kokubo ◽  
H.-M. Kim ◽  
H. Takadama ◽  
M. Uchida ◽  
S. Nishiguchi ◽  
...  
Keyword(s):  
Sol Gel ◽  
Sodium Titanate ◽  
Amorphous Structure ◽  
Apatite Layer ◽  
Apatite Formation ◽  
Titanium Metal ◽  
Oh Groups ◽  
Living Body ◽  
Heat Treated ◽  
Bonelike Apatite

AbstractThe present authors previously showed that titanium metal, which was exposed to 5.OMNaOH solution at 60°C for 24 h and heat-treated at 600°C for 1 h, spontaneously forms a bonelike apatite layer on its surface in the living body, and tightly bonds to the bone through the apatite layer. In the present study, mechanism of the apatite formation on the bioactive titanium metal was investigated in an acellular simulated body fluid (SBF). A thin sodium titanate layer was formed on the surface of the titanium metal by the NaOH and heat treatments. The sodium titanate layer released Na+ ions via exchange with H3O+ ions in SBF, to form a lot of Ti-OH groups on its surface. The Ti-OH groups first combined with Ca2+ ions in SBF, and then later with PO43- ions to form the apatite. Titania and Na2O-TiO2 gels prepared by a sol-gel method as model substances of the sodium titanate layer on the surface of the titanium metal showed that Ti-OH groups of anatase structure are effective for the apatite nucleation, whereas those of amorphous structure and Na2Ti5O11 crystal are not effective.

Improvement of Apatite-Forming Ability of Titanium Metal Enriched with Calcium Ion on its Surface

2008 ◽  
Vol 396-398 ◽  
pp. 341-344 ◽  
Author(s):  
Takashi Kizuki ◽  
Hiroaki Takadama ◽  
Tomiharu Matsushita ◽  
Takashi Nakamura ◽  
Tadashi Kokubo
Keyword(s):  
Calcium Ion ◽  
Scratch Resistance ◽  
Calcium Titanate ◽  
Titanium Metal ◽  
Ultrapure Water ◽  
Living Body ◽  
Humid Environment ◽  
Heat Treated ◽  
Living Bone ◽  
Bonelike Apatite

It has been shown that titanium metal subjected to NaOH and heat treatments spontaneously forms a bonelike apatite on its surface in the living body and bonds to living bone. However, its apatite-forming ability was liable to decrease when the treated titanium metal was stored in humid environment. In the present study, the NaOH-treated titanium metal was soaked in a CaCl2 solution at 40°C for 24h, heat-treated at 600°C for 1h, and then soaked in ultrapure water at 80°C for 24h. Calcium titanate was formed on the surface of the titanium metal 1µm in thickness by these treatments. The resultant titanium metal showed high scratch resistance and high apatite-forming ability in a simulated body fluid. This high apatite-forming ability was maintained even after the titanium metal was kept in 95% relative humidity at 80°C for 1 week.

Preparation of Bioactive Nanophase Titania Ceramics by Alkali-Heat Treatment

2005 ◽  
Vol 288-289 ◽  
pp. 215-218 ◽  
Author(s):  
Qi Feng Yu ◽  
Bang Cheng Yang ◽  
Yao Wu ◽  
Xing Dong Zhang
Keyword(s):  
Thin Film ◽  
Heat Treatment ◽  
Sodium Titanate ◽  
Apatite Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Naoh Solution ◽  
Bonelike Apatite ◽  
Scanning Electron

In this study, alkali-heat treatment in NaOH solution and heat treatment, which could form amorphous sodium titanate on nanophase titania ceramics surface by conditioning the process, was employed to modify the structure and bioactivity of biomedical titania ceramics. After the nanophase titania ceramics was subjected to alkali-heat treatment, thin film X-ray diffraction and scanning electron microscopy results showed the titania ceramics surfaces were covered by porous sodium titanate. In fast calacification solution (FCS), the alkali-heat treated titania ceramics could induce bonelike apatite formation on its surface. Our results showed that induction of apatite-forming ability on titania ceramics could be attained by alkali-heat treatment. So it was an effective way to prepare bioactive titania ceramics by combining sintering and alkali-heat treatment.

Morphological Study of Apatite Formation on NaOH- and Heat-Treated Titanium Metal

2008 ◽  
Vol 396-398 ◽  
pp. 361-364 ◽  
Author(s):  
Seiji Yamaguchi ◽  
Hiroaki Takadama ◽  
Tomiharu Matsushita ◽  
Takashi Nakamura ◽  
Tadashi Kokubo
Keyword(s):  
Cross Section ◽  
Body Fluid ◽  
Morphological Study ◽  
Sodium Titanate ◽  
Apatite Formation ◽  
Titanium Metal ◽  
Sodium Hydrogen ◽  
Heat Treated ◽  
Living Bone ◽  
Hydrogen Titanate

Surface structural change of titanium metal with NaOH and heat treatments and the subsequent soaking in a simulated body fluid (SBF) was investigated by observing cross section of its surface layer by scanning electron microscope. A layer of lathlike phase of sodium hydrogen titanate was formed on the surface of the titanium metal 1 µm in thickness by the NaOH treatment. This was transformed into a layer of lathlike form a little densified of sodium titanate and rutile by the subsequent heat treatment. In SBF, apatite started to precipitate in the interior of the surface lathlike layer, filled the interspaces of the lathlike phases and grew over the surface. This integration of the apatite with the surface lathlike layer might be responsible for the strong bonding of the titanium metal to the living bone.

Biomimetic Magnetic Nanoparticles for Hyperthermia Treatment

2011 ◽  
Vol 493-494 ◽  
pp. 16-19
Author(s):  
E.M. Múzquiz-Ramos ◽  
Dora A. Cortés-Hernández ◽  
C.G. Sánchez-Torres ◽  
José C. Escobedo-Bocardo ◽  
A. Zugasti ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Sol Gel ◽  
Apatite Layer ◽  
Apatite Formation ◽  
Temperature Profiles ◽  
Osteosarcoma Cell ◽  
Hyperthermia Treatment ◽  
Before And After ◽  
Magnetite Particles ◽  
Co Precipitation

The aim of this work was the synthesis of bioactive magnetic particles (BMP) which are expected to form a thin apatite layer on its surface that may bond to bone with the osseous carcinogen tissue. Magnetite and Mg0.6Ca0.4Fe2O4 nanoparticles were obtained by a reverse co-precipitation and sol-gel methods, respectively. Magnetite particles were coated with chitosan in order to obtain a stable ferrofluid. Then both ferrites were biomimetically treated using two different simulated body fluids (SBF and 1.5 SBF). An apatite layer was formed on both types of BMP after the biomimetic treatment. Both ferrites showed superparamagnetic behavior before and after the apatite formation. Their time-dependent temperature profiles were measured under the effect of an AC magnetic field (AMF). After less than 20 min of applying the AMF an appropriate temperature for hyperthermia treatment was obtained. No citotoxicity was observed after osteosarcoma cell culture testing of BMP. Furthermore, after applying an AMF to the cells in contact with the BMP, the cells viability decreased considerably.

Bonelike Apatite Formation on Anodically Oxidized Titanium Metal in Simulated Body Fluid

2003 ◽  
Vol 254-256 ◽  
pp. 459-462 ◽  
Author(s):  
Kawashita Masakazu ◽  
Xin-Yu Cui ◽  
Hyun Min Kim ◽  
Tadashi Kokubo ◽  
Takashi Nakamura
Keyword(s):  
Simulated Body Fluid ◽  
Body Fluid ◽  
Apatite Formation ◽  
Titanium Metal ◽  
Bonelike Apatite

Use of Wollastonite in a Biomimetic Method to Promote Apatite Formation on a Co-Cr-Mo Alloy

2005 ◽  
Vol 284-286 ◽  
pp. 239-242 ◽  
Author(s):  
Dora A. Cortés-Hernández ◽  
A. Medina Ramírez ◽  
José C. Escobedo-Bocardo ◽  
M.A. López ◽  
J.M. Almanza-Robles
Keyword(s):  
Aqueous Solution ◽  
Apatite Layer ◽  
Apatite Formation ◽  
Chemically Treated ◽  
Biomimetic Method ◽  
Bonelike Apatite

Wollastonite ceramics was used in a biomimetic method to promote apatite formation on a Co-Cr-Mo alloy (ASTM F-75). The metallic samples were initially chemically treated in a 5M NaOH aqueous solution. The treated samples were immersed for 7 days in SBF on a bed of wollastonite and then immersed 7 or 14 days in 1.5SBF. For comparative purposes no wollastonite was used during the first 7 days in some tests. A homogeneous bonelike apatite layer was formed on the samples immersed in SBF on the wollastonite bed. The morphology and the Ca/P ratio of the layer were closely similar to those observed on the existing bioactive systems. A thinner homogeneous bonelike apatite layer was formed on the samples immersed in SBF and 1.5SBF without using wollastonite. However, the morphology and the Ca/P ratio of this layer differs slightly to that observed on the existing bioactive systems. The immersion of the samples during the first days in SBF on a wollastonite bed improves significantly the quality and thickness of the bonelike apatite layer.

scholarly journals Apatite-forming ability of titanium in terms of pH of the exposed solution

2012 ◽  
Vol 9 (74) ◽  
pp. 2145-2155 ◽  
Author(s):  
Deepak K. Pattanayak ◽  
Seiji Yamaguchi ◽  
Tomiharu Matsushita ◽  
Takashi Nakamura ◽  
Tadashi Kokubo
Keyword(s):  
Surface Charge ◽  
Ph Value ◽  
Alkaline Solutions ◽  
Apatite Formation ◽  
Living Body ◽  
Heat Treated ◽  
Living Bone ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Main Factor

In order to elucidate the main factor governing the capacity for apatite formation of titanium (Ti), Ti was exposed to HCl or NaOH solutions with different pH values ranging from approximately 0 to 14 and then heat-treated at 600°C. Apatite formed on the metal surface in a simulated body fluid, when Ti was exposed to solutions with a pH less than 1.1 or higher than 13.6, while no apatite formed upon exposure to solutions with an intermediate pH value. The apatite formation on Ti exposed to strongly acidic or alkaline solutions is attributed to the magnitude of the positive or negative surface charge, respectively, while the absence of apatite formation at an intermediate pH is attributed to its neutral surface charge. The positive or negative surface charge was produced by the effect of either the acidic or alkaline ions on Ti, respectively. It is predicted from the present results that the bone bonding of Ti depends upon the pH of the solution to which it is exposed, i.e. Ti forms a bone-like apatite on its surface in the living body and bonds to living bone through the apatite layer upon heat treatment after exposure to a strongly acidic or alkaline solution.

scholarly journals Bioactive Titanate Layers Formed on Titanium and Its Alloys by Simple Chemical and Heat Treatments

2015 ◽  
Vol 9 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Tadashi Kokubo ◽  
Seiji Yamaguchi
Keyword(s):  
Sodium Titanate ◽  
Strong Acid ◽  
Heat Treatments ◽  
Calcium Titanate ◽  
Hot Water ◽  
Apatite Formation ◽  
Porous Ti ◽  
Artificial Hip Joint ◽  
Heat Treated ◽  
Naoh Treatment

To reveal general principles for obtaining bone-bonding bioactive metallic titanium, Ti metal was heat-treated after exposure to a solution with different pH. The material formed an apatite layer at its surface in simulated body fluid when heat-treated after exposure to a strong acid or alkali solution, because it formed a positively charged titanium oxide and negatively charged sodium titanate film on its surface, respectively. Such treated these Ti metals tightly bonded to living bone. Porous Ti metal heat-treated after exposure to an acidic solution exhibited not only osteoconductive, but also osteoinductive behavior. Porous Ti metal exposed to an alkaline solution also exhibits osteoconductivity as well as osteoinductivity, if it was subsequently subjected to acid and heat treatments. These acid and heat treatments were not effective for most Ti-based alloys. However, even those alloys exhibited apatite formation when they were subjected to acid and heat treatment after a NaOH treatment, since the alloying elements were removed from the surface by the latter. The NaOH and heat treatments were also not effective for Ti-Zr-Nb-Ta alloys. These alloys displayed apatite formation when subjected to CaCl2treatment after NaOH treatment, forming Ca-deficient calcium titanate at their surfaces after subsequent heat and hot water treatments. The bioactive Ti metal subjected to NaOH and heat treatments has been clinically used as an artificial hip joint material in Japan since 2007. A porous Ti metal subjected to NaOH, HCl and heat treatments has successfully undergone clinical trials as a spinal fusion device.

Bioactive Ti Metal with Ca-Enriched Surface Layer Able to Release Sr Ions

2013 ◽  
Vol 587 ◽  
pp. 269-274 ◽  
Author(s):  
Seiji Yamaguchi ◽  
Shekhar Nath ◽  
Tomiharu Matsushita ◽  
Tadashi Kokubo
Keyword(s):  
Calcium Titanate ◽  
Apatite Formation ◽  
Mixed Solution ◽  
Living Body ◽  
Sodium Hydrogen ◽  
Heat Treated ◽  
Living Bone ◽  
Naoh Solution ◽  
Na Ions ◽  
Phosphate Buffered Saline

Bioactive Ti metal able to release Sr ions was prepared by chemical and heat treatments of Ti metal. Ti metal was initially soaked in 5M NaOH solution to form sodium hydrogen titanate. It was soaked in a mixed solution of CaCl2 and SrCl2 to replace its Na ions with Ca and Sr ions at a given range from 0.18 to 1.62 in Sr/Ca ratio. When it was heat-treated at 600 oC, it formed Sr-containing calcium titanate (SrCT) and rutile. The apatite formation in SBF of the treated metal was low, but increased markedly by subsequently soaking the metal in 1 M SrCl2 solution at 80 oC. Thus, the treated metal gradually released Sr ions into phosphate-buffered saline up to 0.9 ppm. It is expected that the Ti metal formed with the bioactive SrCT layer could release Sr ions in a living body to promote bone formation, and bond to a living bone through an apatite.

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