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1.
Liu GJ Miyaji F Kokubo T Takadama H Nakamura T Murakami A 《Journal of materials science. Materials in medicine》1998,9(5):285-290
A dense and uniform layer of highly bioactive apatite can be formed in arbitrary thickness on any kind and shape of organic polymer substrates by the following biomimetic process. The substrate is first placed in contact with granular particles of CaO, SiO2-based glass soaked in a simulated body fluid with ion concentrations nearly equal to those of human blood plasma for forming apatite nuclei, and then soaked in another fluid highly supersaturated with respect to the apatite for making the apatite nuclei grow. In the present study, the polymer substrates were pretreated with ultraviolet (UV) light, and then subjected to the biomimetic process described above. By UV irradiation, the induction period for the apatite nucleation of poly(ethylene terephthalate) (PET), poly-ether sulphone (PESF), polyethylene (PE), poly(methyl methacrylate) (PMMA) and polyamide 6 (N6) substrates were reduced form 24 h to 10 h. The adhesive strengths of the apatite layer to the substrates increased from 2.5–3.2 MPa to 4.5–6.0 MPa for PET, PESF and PMMA, and from about 1.0 MPa to 4.0–6.5 MPa for PE and N6 substrates. These results have been explained by assuming that silicate ions, which induce apatite nucleation, are easily adsorbed on the substrates due to the formation of polar groups, with an improved hydrophilic nature, on the polymer surfaces by UV irradiation. © 1998 Chapman & Hall 相似文献
2.
Kawai T Ohtsuki C Kamitakahara M Hosoya K Tanihara M Miyazaki T Sakaguchi Y Konagaya S 《Journal of materials science. Materials in medicine》2007,18(6):1037-1042
Modification of organic polymer with silanol groups in combination with calcium salts enables the polymer to show bioactivity,
that is, the polymer forms apatite on its surface after exposure to body environment. However, how modification with silanol
groups influences ability of apatite formation on the polymer substrate and adhesive strength between polymer and apatite
is not yet known. In the present study, polyamide containing carboxyl groups was modified with different amounts of silanol
groups, and its apatite-forming ability in 1.5SBF, which contained ion concentrations 1.5 times those of simulated body fluid
(SBF), was examined. The rate of apatite formation increased with increasing content of silanol groups in the polyamide films.
This may be attributed to enhancement of dipole interactions. A tendency for the adhesive strength of the apatite layer on
the polyamide film to be decreased with increasing content of silanol groups was observed. This may be attributed to swelling
in 1.5SBF and having a high degree of shrinkage after drying. These findings clearly show that modification of organic polymers
with the functional groups induces apatite deposition, and also determines the adhesive strength of the apatite layer to the
organic substrates. 相似文献
3.
Miyaji F Iwai M Kokubo T Nakamura T 《Journal of materials science. Materials in medicine》1998,9(2):61-65
It has been confirmed that the apatite nucleation is induced by silanol (Si–OH) groups formed on the surfaces of materials and/or silicate ions adsorbed on them.It was previously shown that apatite nuclei are formed on organic polymers when the polymers are placed on CaO, SiO2-based glass particles soaked in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma, and that they grow spontaneously to form a dense and uniform apatite layer together with high adhesive strength to the substrates when the polymers are soaked in another solution with ion concentrations 1.5 times the SBF. In the present study, silanol groups bonded covalently to the surface of the silicone substrate were formed and its apatite-forming ability was examined. When silicone substrates were treated with 5 or 10 M NaOH with pH 7.25 at 36.5°C for more than 3 h, silanol groups were formed on the surfaces of the substrates. When thus NaOH-treated substrates were soaked in 1.5SBF at 36.5°C, a bone-like apatite was formed on the substrates in a short period. © 1998 Chapman & Hall. 相似文献
4.
Miyazaki T Ohtsuki C Akioka Y Tanihara M Nakao J Sakaguchi Y Konagaya S 《Journal of materials science. Materials in medicine》2003,14(7):569-574
The development of organic–inorganic hybrids composed of hydroxyapatite and organic polymers is attractive because of their novelty in being materials that show a bone-bonding ability, i.e. bioactivity, and because they have mechanical properties similar to those of natural bone. The biomimetic process has received much attention for fabricating such a hybrid, where bone-like apatite is deposited under ambient conditions on polymer substrates in a simulated body fluid (SBF) having ion concentrations nearly equal to those of human extracellular fluid or related solutions. It has been shown that the carboxyl group is effective for inducing heterogeneous nucleation of apatite in the body. In the present study, apatite deposition on polyamide films containing various numbers of carboxyl groups was investigated in 1.5 SBF, which had ion concentrations 1.5 times those of a normal SBF. The effect of incorporation of calcium chloride on the formation of apatite was examined. Polyamide films containing 33 mol % CaCl2 did not form apatite, even after soaking in 1.5 SBF for 7 days, and even when the polymer film contained 50 mol % carboxyl group. On the other hand, those modified with 40 mass % CaCl2 formed apatite on their surfaces in 1.5 SBF. The ability of the modified film to form an apatite layer increased, and the adhesion of the apatite layer bonded to the film improved, with increasing carboxyl group content. It is concluded that novel apatite–polyamide hybrids can be prepared by a biomimetic process. 相似文献
5.
Composition and structure of apatite formed on organic polymer in simulated body fluid with a high content of carbonate ion 总被引:3,自引:0,他引:3
Kim HM Kishimoto K Miyaji F Kokubo T Yao T Suetsugu Y Tanaka J Nakamura T 《Journal of materials science. Materials in medicine》2000,11(7):421-426
Apatite layer was formed on polyethyleneterephthalate (PET) substrate by the following biomimetic process. The PET substrate was placed on granular particles of a CaO, SiO2-based glass in simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma to form apatite nuclei on their surfaces. The apatite nuclei was then grown into a continuous layer by subsequently soaking the substrate in SBF under air or CO2 atmosphere in which CO2 partial pressure in the ambient was adjusted to 14.8 kPa to increase the content of carbonate ion to a level nearly equal to that of blood plasma. The increase in the content of carbonate ions in SBF changed the Ca/P atomic ratio of the apatite from 1.51 to 1.63, content of CO3
2- ions from 2.64 to 4.56 wt %, and lattice constants a from 94.32 to 94.23 nm and c from 68.70 to 68.83 nm, respectively. The Ca/P ratio and lattice constants of the apatite formed in SBF under CO2 atmosphere were approximately identical to those of bone apatite, i.e. Ca/P atomic ratio 1.65, content of CO3
2- ion 5.80 wt % and lattice constants a 94.20 and c 68.80 nm. This indicates that an apatite with composition and structure nearly identical to those of bone apatite can be produced in SBF by adjusting its ion concentrations including the content of carbonate ions to be equal to those of blood plasma. 相似文献
6.
Jin HH Lee CH Kim DH Kim TW Hwang KH Lee JK Park HC Yoon SY 《Journal of nanoscience and nanotechnology》2011,11(8):7438-7441
The apatite was formed on the titanium plates with NaOH and heat treatments by biomimetic process. The influence of titanium surface microstructure on the apatite formation onto titanium substrate in SBF solution was investigated. After biomimetic process, nano-sized apatite layers were found on the Ti plates with NaOH and heat treatments. However, the morphologies of formed apatite on substrate had different shapes such as coated, load-like, and linked. The morphology of apatite formed by biomimetic process would be affected by alkaline treatment, and substrate morphology and phase. 相似文献
7.
8.
Leonor IB Kim HM Balas F Kawashita M Reis RL Kokubo T Nakamura T 《Journal of materials science. Materials in medicine》2007,18(10):1923-1930
Covalent coupling of sulfonic group (–SO3H) was attempted on different polymers to evaluate efficacy of this functional group in inducing nucleation of apatite in
body environment, and thereupon to design a simple biomimetic process for preparing bonelike apatite-polymer composites. Substrates
of polyethylene terephthalate (PET), polycaprolactam (Nylon 6), high molecular weight polyethylene (HMWPE) and ethylene-vinyl
alcohol co-polymer (EVOH) were subjected to sulfonation by being soaked in sulfuric acid (H2SO4) or chlorosulfonic acid (ClSO3H) with different concentrations. In order to incorporate calcium ions, the sulfonated substrates were soaked in saturated
solution of calcium hydroxide (Ca(OH)2). The treated substrates were soaked in a simulated body fluid (SBF). Fourier transformed infrared spectroscopy, thin-film
X-ray diffraction, and scanning electron microscopy showed that the sulfonation and subsequent Ca(OH)2 treatments allowed formation of –SO3H groups binding Ca2+ ions on the surface of HMWPE and EVOH, but not on PET and Nylon 6. The HMWPE and EVOH could thus form bonelike apatite layer
on their surfaces in SBF within 7 d. These results indicate that the –SO3H groups are effective for inducing apatite nucleation, and thereby that surface sulfonation of polymers are effective pre-treatment
method for preparing biomimetic apatite on their surfaces. 相似文献
9.
Miyazaki T Kim HM Kokubo T Ohtsuki C Kato H Nakamura T 《Journal of materials science. Materials in medicine》2002,13(7):651-655
Tantalum metal is a candidate for use as an implant material in high load-bearing bony defects, due to its attractive features such as high fracture toughness and high workability. This metal, however, does not have bone-bonding ability, i.e. bioactivity, and therefore the development of bioactive tantalum metal is highly desirable. It is known that the essential prerequisite for an artificial material to show bioactivity is to form a bonelike apatite layer on its surface in the body environment. The same type of apatite layer is formed in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma. The present authors previously showed that the apatite formation on tantalum metal in SBF was remarkably accelerated by treatment with 0.5 M-NaOH aqueous solution and subsequent firing at 300 °C, while untreated tantalum metal spontaneously formed the same apatite after a long soaking period. In the present study, the bonding strength of the apatite layer to the substrate was quantitatively evaluated in comparison with that to the untreated tantalum metal. Adhesive strength was measured as an estimation of bonding strength, and the surface microstructure of both the substrates was characterized in order to discuss the difference in the bonding strength in terms of surface structure. The apatite layer formed on the NaOH- and heat-treated tantalum metal shows higher adhesive strength than that formed on the untreated metal. The amorphous sodium tantalate layer formed on the tantalum metal by NaOH and heat treatments, has a smooth graded structure where its concentration gradually changes from the surface into the interior metal. Smooth graded structure with complex of apatite is constructed after soaking in SBF. The higher bonding strength of the apatite layer formed on the treated metal is attributed to its smooth graded structure. 相似文献
10.
K. Fatehi F. Moztarzadeh M. Solati-Hashjin M. Tahriri M. Rezvannia R. Ravarian 《Bulletin of Materials Science》2008,31(2):101-108
Titanium alloy (Ti6A14V) substrates, having the ability of biomimetic calcium phosphate-based materials, especially hydroxyapatite
deposition in a simulated body fluid (SBF) means of chemical treatment (alkaline treatment) and subsequent heat treatment,
was studied. The effects of alkaline treatment time, concentration and heat treatment temperature on the formation of calcium
phosphate (carbonate-hydroxyapatite) on Ti6A14V surface were examined. For this purpose, the metallic substrates were treated
in 0, 5 and 10 M NaOH solutions at a temperature of 60 or 80°C for 1 and 3 days. Subsequently the substrate was heat-treated
at 500, 600 and 700°C for 1 h for consolidation of the sodium titanate hydrogel layer. Finally, they were soaked in SBF for
1 and 3 days. The substrate surfaces were characterized by the techniques commonly used for bulk material such as scanning
electron microscopy (SEM) and thin film X-ray diffraction (TF-XRD). With regard to the SEM and TF-XRD results, the optimum
process consists of 3 days soaking in 5 M NaOH in 80°C and subsequent heat treatment at 600°C for 1h. It is worth mentioning
that the results showed that the apatite formed within 3 days on the specimen surfaces, however, there was no sign of apatite
formation in the control samples (without alkaline and heat treatment) which was treated for up to 3 days immersion in SBF. 相似文献
11.
Seiji Yamaguchi Takeshi Yabutsuka Mitsuhiro Hibino Takeshi Yao 《Materials science & engineering. C, Materials for biological applications》2009,29(5):1584-1588
Electrophoretic deposition (EPD), which is normally available on electric conductive materials, was applied to insulating materials. Wollastonite particles were deposited into the pores of porous alumina and porous ultrahigh molecular weight polyethylene (UHMWPE) substrates by EPD to yield alumina-wollastonite and UHMWPE-wollastonite composites, respectively. These composites were soaked in simulated body fluid (SBF) to evaluate their apatite-forming ability. Apatite was induced from the wollastonite particles, which grew on the surfaces and covered the entire composite surfaces. The bonding strength of the apatite layer to the substrates was as high as 8.9 MPa for alumina and 5.2 MPa for UHMWPE due to an interlocking effect. Thus, the formed alumina-wollastonite and UHMWPE-wollastonite composites should be useful as bone substitutes. 相似文献
12.
In previous studies, Zr gained apatite‐forming ability by various methods; however, it took more than 7 days in simulated body fluid (SBF) to gain apatite‐forming ability. In this study, the authors developed the method to achieve apatite‐forming ability in Zr alloy within 1 day in SBF by a combination with apatite nuclei that promote apatite formation in SBF. First, Zr–Sn alloy was soaked in concentrated sulphuric acid, and pores in micro‐level were formed on the surface of Zr–Sn alloy. To attain apatite forming ability in Zr–Sn alloy, second, apatite nuclei were formed in the micropores. To evaluate apatite‐forming ability, thus‐obtained Zr–Sn alloy with apatite nuclei was soaked in SBF; hydroxyapatite formation was observed on the whole surface of the Zr–Sn alloy plates. From this result, it was clarified that higher apatite‐forming ability was attained on the apatite nuclei‐treated Zr–Sn alloy with micropores in comparison with that without micropores. When adhesive strength of formed hydroxyapatite film with respect to Zr–Sn alloy plates was measured, high‐adhesive strength of the formed apatite film was attained by forming micropores and subsequently precipitating apatite nuclei in the fabrication process because of an interlocking effect caused by hydroxyapatite formed in the micropores.Inspec keywords: precipitation, zirconium alloys, calcium compounds, bioceramics, tin alloys, adhesion, thin filmsOther keywords: apatite forming ability, micropore formation, hydroxyapatite film, bioactive zirconium‐tin alloy, apatite nuclei‐treated zirconium‐tin alloy, zirconium‐tin alloy plates, simulated body fluid, concentrated sulphuric acid, hydroxyapatite formation, adhesive strength, precipitating apatite nuclei, time 1.0 d, ZrSn, Ca10 (PO4)6 (OH)2 相似文献
13.
Kokubo T Ueda T Kawashita M Ikuhara Y Takaoka GH Nakamura T 《Journal of materials science. Materials in medicine》2008,19(2):695-702
A rectangular specimen of polyethylene terephthalate (PET) was soaked in a titania solution composed of titanium isopropoxide,
water, ethanol and nitric acid at 25 °C for 1 h. An amorphous titanium oxide was formed uniformly on the surface of PET specimen,
but did not form an apatite on its surface in a simulated body fluid (SBF) within 3 d. The PET plate formed with the amorphous
titanium oxide was subsequently soaked in water or HCl solutions with different concentrations at 80 °C for different periods
of time. The titanium oxide on PET was transformed into nano-sized anatase by the water treatment and into nano-sized brookite
by 0.10 M HCl treatment at 80 °C for 8 d. The former did not form the apatite on its surface in SBF within 3 d, whereas the
latter formed the apatite uniformly on its surface. Adhesive strength of the titanium oxide and apatite layers to PET plate
was increased by pre-treatment of PET with 2 wt% NaOH solution at 40 °C for 2 h. A two-dimensional fabric of PET fibers 24 μm
in diameter was subjected to the NaOH pre-treatment at 40 °C, titania solution treatment at 25 °C and subsequent 0.10 M HCl
treatment at 80 °C. Thus treated PET fabric formed the apatite uniformly on surfaces of individual fibers constituting the
fabric in SBF within 3 d. Two or three dimensional PET fabrics modified with the nano-sized brookite on surfaces of the individual
fibers constituting the fabric by the present method are believed to be useful as flexible bone substitutes, since they could
be integrated with living bone through the apatite formed on their constituent fibers. 相似文献
14.
Anahi H. Aparecida Marcus V. L. Fook Antonio C. Guastaldi 《Journal of materials science. Materials in medicine》2009,20(6):1215-1222
Modifications were performed on a biomimetic solution (SBF), according to previous knowledge on the behavior of ions present
in its composition, in order to obtain apatite coatings onto Ultra-High Molecular Weight Polyethylene (UHMWPE) without having
to use polymer pre-treatments that could compromise its properties. UHMWPE substrates were immersed into a 30% H2O2 solution for a 24-h period and then submitted to a biomimetic coating method using standard SBF and two other modified SBF
solutions. Apatite coatings were only obtained onto UHMWPE when the modified SBF solutions were used. Based on these results,
apatite coatings of biological importance (calcium-deficient hydroxyapatite—CDHA, amorphous calcium phosphate—ACP, octacalcium
phosphate—OCP, and carbonated HA) can be obtained onto UHMWPE substrates, allowing an adequate conciliation between bonelike
mechanical properties and bioactivity. 相似文献
15.
《Composites Part A》1999,30(4):405-409
A biomimetic process was developed to prepare apatite–metal and apatite–polymer composites. A variety of metals and organic polymers incorporated surface functional groups such as Si–OH, Ti–OH or Ta–OH to induce formation of a biologically active bonelike apatite by chemical treatment or physical adsorption. Subsequent immersion in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma or 1.5 SBF led to the formation of a dense and uniform bonelike apatite layer on the surface. Apatite–metal and apatite–polymer composites prepared in this way are believed to be very useful as artificial bone substitutes. 相似文献
16.
Balas F Kokubo T Kawashita M Nakamura T 《Journal of materials science. Materials in medicine》2007,18(6):1167-1174
Polyethylene (PE), polyethylene terephthalate (PET), ethylene-vinyl alcohol copolymer (EVOH), and poly(ε-caprolactam) (Nylon
6) were successfully modified with a thin crystalline titanium oxide layer on their surfaces by a simple dipping into a titanium
alkoxide solution and a subsequent soak in hot HCl solution, without the aid of a silane-coupling agent. The surface modified
polymers formed a bone-like apatite layer in a simulated body fluid (SBF) within a period of 2 days. PE, PET, and Nylon 6
formed an apatite layer faster and had a higher adhesive strength to the apatite. Three-dimensional fabrics with open spaces
in various sizes containing such surface modified polymer fibers are expected to be useful as bone substitutes, since they
may be able to form apatite on their constituent fibers in the living body, and thus, integrate with living bone. 相似文献
17.
A biomimetic method was used to promote a bioactive surface on a CoCrMo alloy (ASTM F75). To enhance the nucleation of apatite on the metallic substrate, wollastonite ceramics (W), bioactive glass (BG) or hydroxyapatite (HA) were used in the biomimetic method. Metallic samples were chemically treated and immersed for 7 days in SBF on a bed of bioactive material (W, BG or HA) followed by an immersion in 1.5SBF for 7 or 14 days without bioactive system.A bonelike apatite layer was formed on the surface of all the samples tested. The samples treated with wollastonite showed a higher rate of apatite formation and the morphology of the layer was closer to that of the existing bioactive systems. A higher crystallinity of the apatite layer was also observed by using wollastonite. The pH of the SBF, the Ca/P ratio and the thickness of the layer on the samples treated with wollastonite and bioactive glass increased as increasing the immersion time. The thickness of the layer on the samples treated with hydroxyapatite also increased with time, but the pH of the SBF and the Ca/P ratio changed with no a defined trend. 相似文献
18.
Chen Y Mak AF Wang M Li JS Wong MS 《Journal of materials science. Materials in medicine》2008,19(6):2261-2268
To investigate the methods to improve the cell–material interaction of devices or tissue engineering scaffolds made of poly(l-lactic acid) (PLLA) polymer, apatite and apatite/collagen composite coatings were formed on PLLA films within 24 h through
accelerated biomimetic processes. In vitro investigation using Saos-2 osteoblast-like cells through cell culture was conducted
to assess the biological performance of these biomimetic coatings. The cell morphology on three types of surfaces, viz., PLLA
film, PLLA film with the apatite coating, and PLLA film with the apatite/collagen composite coating, was studied using scanning
electron microscopy (SEM). Cell viability was estimated using the MTT assay. The differentiated cell function was assessed
by measuring the alkaline phosphatase (ALP) activity. The results obtained indicated that the biomimetic apatite and apatite/collagen
composite coatings could significantly enhance the proliferation and differentiation of osteoblast-like cells. The apatite/collagen
composite coating appears to be promising for the surface modification of PLLA-based devices with much improved interactions
with osteoblastic cells. 相似文献
19.
Väkiparta M Forsback AP Lassila LV Jokinen M Yli-Urpo AU Vallittu PK 《Journal of materials science. Materials in medicine》2005,16(9):873-879
The aim of this study was to investigate the biomimetic mineralization on the surface of a glass fiber reinforced composite with partially resorbable biopolymer matrix. The E-glass fibers were preimpregnated with a novel biopolymer of poly(hydroxyproline) amide, and further impregnated in the monomer system of bis-phenyl glycidyl dimethacrylate (Bis-GMA)—triethylene glycol dimethacrylate (TEGDMA), which formed interpenetrating polymer networks (IPN) with the preimpregnation polymer. After light-initiated polymerization of the monomer system, the rhombic test specimens (n = 6) were immersed in the simulated body fluid (SBF) with the bioactive glass for 24 h, and then the apatite nuclei were allowed to grow for 1, 3, 5 and 7 days in the SBF. The control test specimens (n = 3) were immersed in SBF without the bioactive glass. According to the scanning electron microscope (SEM), a mineral layer was formed on the surface of all the specimens, which were immersed with bioactive glass. The layer was thickened by the prolonged immersion time to a uniform layer. The Ca/P atomic ratio of the mineral varied between 1.30 and 1.54 as analyzed by the energy dispersive X-ray analysis (EDXA). The Fourier transform infrared spectroscopy (FT-IR) spectra gave signals for the mineral, which are characteristic of both bone-like apatite and orthocalciumphosphate. In conclusion, the mineral layer was formed on the surfaces of the specimens by biomimetic mineralization, the mineral being a mixture of bone-like apatite, orthocalciumphosphate and other calcium phosphates. 相似文献
20.
A biodegradable polymer coated with a bonelike apatite layer on its surface would be useful as a scaffold for bone tissue
regeneration. In this study, poly(l-lactic acid) (PLLA) was treated with oxygen plasma to produce oxygen-containing functional groups on its surface. The plasma-treated
specimen was then alternately dipped in aqueous CaCl2 and K2HPO4·3H2O solutions three times, to deposit apatite precursors onto the surface. The surface-modified specimen then successfully formed
a dense and uniform bonelike surface apatite layer after immersion for 24 h in a simulated body fluid with ion concentrations
approximately equal to those of human blood plasma. The adhesive strength between the apatite layer and the specimen surface
increased as the power density of the oxygen plasma used increased. The maximum adhesive strength of the apatite layer to
the specimen was significantly higher than that to the commercially available artificial bone, HAPEXTM. The resultant bonelike apatite–PLLA composite would be useful as a scaffold for bone tissue regeneration. 相似文献