The Experts below are selected from a list of 9768 Experts worldwide ranked by ideXlab platform
Yi Zeng - One of the best experts on this subject based on the ideXlab platform.
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fabrication of fibrous poly butylene succinate wollastonite apatite composite scaffolds by electrospinning and Biomimetic Process
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: Darning Zhang, Jiang Chang, Yi ZengAbstract:In this paper, a novel kind of Poly(butylene succinate) (PBSU) /wollastonite/apatite composite scaffold was fabricated via electrospinning and Biomimetic Process. Pure PBSU scaffold and composite scaffolds with 12.5 wt% and 25 wt% wollastonite were firstly fabricated by electrospinning. SEM micrographs showed that all the electrospun scaffolds had homogeneous fibrous structures with interconnected pores and randomly oriented ultrafine fibers. The composite scaffolds were then surface modified using a Biomimetic Process. SEM and XRD results showed that apatite could deposit on the surfaces of the composite fibers after incubation in SBF and a novel fibrous structure with microspheres composed of worm-like apatite on composite fibers was formed. Incubation time and wollastonite content were found to influence the morphology of the scaffolds during the Biomimetic Process obviously. Both the amount and the size of the microspheres on the composite scaffolds increased with increased incubation time. After a certain incubation time, microspheres formed on the composite fibers with less wollastonite had a relatively larger size. Therefore, the microstructure of the composite scaffolds could be adjusted by controlling the wollastonite content and the incubation time. All of these results suggest that it is an effective approach to fabricate PBSU/wollastonite/apatite fibrous composite scaffolds with different material content and controllable microstructure for bone tissue engineering.
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Fabrication of fibrous poly(butylene succinate)/wollastonite/apatite composite scaffolds by electrospinning and Biomimetic Process
Journal of materials science. Materials in medicine, 2007Co-Authors: Darning Zhang, Jiang Chang, Yi ZengAbstract:In this paper, a novel kind of Poly(butylene succinate) (PBSU) /wollastonite/apatite composite scaffold was fabricated via electrospinning and Biomimetic Process. Pure PBSU scaffold and composite scaffolds with 12.5 wt% and 25 wt% wollastonite were firstly fabricated by electrospinning. SEM micrographs showed that all the electrospun scaffolds had homogeneous fibrous structures with interconnected pores and randomly oriented ultrafine fibers. The composite scaffolds were then surface modified using a Biomimetic Process. SEM and XRD results showed that apatite could deposit on the surfaces of the composite fibers after incubation in SBF and a novel fibrous structure with microspheres composed of worm-like apatite on composite fibers was formed. Incubation time and wollastonite content were found to influence the morphology of the scaffolds during the Biomimetic Process obviously. Both the amount and the size of the microspheres on the composite scaffolds increased with increased incubation time. After a certain incubation time, microspheres formed on the composite fibers with less wollastonite had a relatively larger size. Therefore, the microstructure of the composite scaffolds could be adjusted by controlling the wollastonite content and the incubation time. All of these results suggest that it is an effective approach to fabricate PBSU/wollastonite/apatite fibrous composite scaffolds with different material content and controllable microstructure for bone tissue engineering.
Jiang Chang - One of the best experts on this subject based on the ideXlab platform.
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preparation of bone like apatite collagen nanocomposites by a Biomimetic Process with phosphorylated collagen
Journal of Biomedical Materials Research Part A, 2008Co-Authors: Jiang ChangAbstract:By imitating in vivo bone mineralization, bone-like apatite-collagen nanocomposites were prepared by chemical phosphorylation of collagen and subsequent Biomimetic growth of bone-like nanoapatite on collagen nanofibers. Two steps were employed in the composites preparation. First, the collagen was phosphorylated by chemical treatment, which provides the nucleation sites for bone-like apatite mineralization. The subsequent growth of bone-like nanoapatite on the phosphorylated collagen nanofibers was performed in simulated body fluid (SBF). The characterization of the composites showed that the composites were composed of nanoapatite mineralized collagen nanofibers that exhibit similarity to natural bone in composition and crystal morphology.
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fabrication of fibrous poly butylene succinate wollastonite apatite composite scaffolds by electrospinning and Biomimetic Process
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: Darning Zhang, Jiang Chang, Yi ZengAbstract:In this paper, a novel kind of Poly(butylene succinate) (PBSU) /wollastonite/apatite composite scaffold was fabricated via electrospinning and Biomimetic Process. Pure PBSU scaffold and composite scaffolds with 12.5 wt% and 25 wt% wollastonite were firstly fabricated by electrospinning. SEM micrographs showed that all the electrospun scaffolds had homogeneous fibrous structures with interconnected pores and randomly oriented ultrafine fibers. The composite scaffolds were then surface modified using a Biomimetic Process. SEM and XRD results showed that apatite could deposit on the surfaces of the composite fibers after incubation in SBF and a novel fibrous structure with microspheres composed of worm-like apatite on composite fibers was formed. Incubation time and wollastonite content were found to influence the morphology of the scaffolds during the Biomimetic Process obviously. Both the amount and the size of the microspheres on the composite scaffolds increased with increased incubation time. After a certain incubation time, microspheres formed on the composite fibers with less wollastonite had a relatively larger size. Therefore, the microstructure of the composite scaffolds could be adjusted by controlling the wollastonite content and the incubation time. All of these results suggest that it is an effective approach to fabricate PBSU/wollastonite/apatite fibrous composite scaffolds with different material content and controllable microstructure for bone tissue engineering.
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Fabrication of fibrous poly(butylene succinate)/wollastonite/apatite composite scaffolds by electrospinning and Biomimetic Process
Journal of materials science. Materials in medicine, 2007Co-Authors: Darning Zhang, Jiang Chang, Yi ZengAbstract:In this paper, a novel kind of Poly(butylene succinate) (PBSU) /wollastonite/apatite composite scaffold was fabricated via electrospinning and Biomimetic Process. Pure PBSU scaffold and composite scaffolds with 12.5 wt% and 25 wt% wollastonite were firstly fabricated by electrospinning. SEM micrographs showed that all the electrospun scaffolds had homogeneous fibrous structures with interconnected pores and randomly oriented ultrafine fibers. The composite scaffolds were then surface modified using a Biomimetic Process. SEM and XRD results showed that apatite could deposit on the surfaces of the composite fibers after incubation in SBF and a novel fibrous structure with microspheres composed of worm-like apatite on composite fibers was formed. Incubation time and wollastonite content were found to influence the morphology of the scaffolds during the Biomimetic Process obviously. Both the amount and the size of the microspheres on the composite scaffolds increased with increased incubation time. After a certain incubation time, microspheres formed on the composite fibers with less wollastonite had a relatively larger size. Therefore, the microstructure of the composite scaffolds could be adjusted by controlling the wollastonite content and the incubation time. All of these results suggest that it is an effective approach to fabricate PBSU/wollastonite/apatite fibrous composite scaffolds with different material content and controllable microstructure for bone tissue engineering.
Tadashi Kokubo - One of the best experts on this subject based on the ideXlab platform.
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Effects of solution on apatite formation on substrate in Biomimetic Process
Journal of the Ceramic Society of Japan, 2001Co-Authors: Yoshio Abe, Tadashi Kokubo, Masakazu Kawashita, T NakamuraAbstract:An alumina substrate forms a dense and uniform layer of bone-like apatite on it, when it is soaked in a simulated body fluid, provided that it is faced to a glass of composition, MgO 4.6, CaO 44.7, SiO2 34.0, P2O5 16.2 and CaF2 0.5mass%, placed at a distance of 0.2mm. Effect of the ion concentrations, pH and temperatures of the fluid on the apatite formation on the substrate were investigated. The bone-like carbonate apatite was formed even in fluids lacking in calcium or phosphate ion, since those ions and carbonate ions are supplied from the glass and the surrounding fluids, respectively. An apatite was formed in fluids with pH 6.53 to 7.48 but not in those with pH less than 5.00, because the apatite is stable only in neutral to basic environment. Apatite formed in fluids at 30 to 60°C but not below 20°C, since only a small amount of silicate ions is released from the glass at lower temperatures.
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in vitro bone formation on a bone like apatite layer prepared by a Biomimetic Process on a bioactive glass ceramic
Journal of Biomedical Materials Research, 2000Co-Authors: C Loty, Tadashi Kokubo, H.-m. Kim, J M Sautier, Habib Boulekbache, N ForestAbstract:In this study we have investigated the behavior of fetal rat osteoblasts, cultured up to 23 days, on a bioactive apatite-wollastonite (AW) glass-ceramic and on the same material on which a carbonated apatite layer had been formed by a Biomimetic Process (AWa). At the last day of culture, the specific activity of alkaline phosphatase activity, as determined biochemically, was about 30% greater on AWa compared with AW disks. After the cell layers had been scraped off, scanning electron microscopic (SEM) observations of the materials' surfaces revealed that mineralized bone nodules remained attached to both surfaces but in larger amounts on AWa. X-ray microanalysis indicated the presence of calcium (Ca) and phosphorus (P) in the bone tissue throughout the AWa surface and Ca, P, and silicon (Si) on the AW surface. The AW/ and AWa/bone interfaces also were analyzed after fracturing of the disks. The interfacial analysis showed firm bone bonding to the AW and AWa surfaces, confirmed by the X-ray microanalytic mappings. These results indicate the importance of surface composition in supporting differentiation of osteogenic cells and the subsequent apposition of bone matrix, which allows a strong bond of the bioactive materials to the bone. Furthermore, prefabrication of a biologic apatite layer by a method that mimics biomineralization could find application to bone-repairing materials.
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ceramic metal and ceramic polymer composites prepared by a Biomimetic Process
Composites Part A-applied Science and Manufacturing, 1999Co-Authors: Tadashi Kokubo, H.-m. Kim, Fumiaki Miyaji, Hiroaki Takadama, Toshiki MiyazakiAbstract: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.
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Ceramic–metal and ceramic–polymer composites prepared by a Biomimetic Process
Composites Part A: Applied Science and Manufacturing, 1999Co-Authors: Tadashi Kokubo, H.-m. Kim, Fumiaki Miyaji, Hiroaki Takadama, Toshiki MiyazakiAbstract: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.
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apatite organic polymer composites prepared by a Biomimetic Process improvement in adhesion of the apatite layer to the substrate by ultraviolet irradiation
Journal of Materials Science: Materials in Medicine, 1998Co-Authors: G J Liu, Tadashi Kokubo, T Nakamura, Fumiaki Miyaji, Hiroaki Takadama, A MurakamiAbstract: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
Ayako Oyane - One of the best experts on this subject based on the ideXlab platform.
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Calcium phosphate coating on dental composite resins by a laser-assisted Biomimetic Process
Heliyon, 2018Co-Authors: A. Joseph Nathanael, Ayako Oyane, Maki Nakamura, Erika Nishida, Kenji Koga, Saori Tanaka, Hirofumi MiyajiAbstract:Abstract Objectives Dental composite resins with better biocompatibility and osteoconductivity have been sought in endodontic treatments. This study aimed to develop a technique to produce the osteoconductive resin surfaces through calcium phosphate (CaP) coating using a laser-assisted Biomimetic (LAB) Process. Methods Light-cured, acrylic-based composite resins were used as substrates. The resin substrate was subjected to a LAB Process comprising Nd:YAG pulsed laser irradiation in a supersaturated CaP solution. The LAB-Processed substrate was immersed for 3 days in a simulated body fluid (SBF) for the preliminary osteoconductivity assessment. Results After irradiation for 30 min, the resin surfaces were partly coated with a newly formed CaP layer. The coating layer contained hydroxyapatite as the main crystalline phase and the coating coverage depended on the laser wavelength and the type of resin. The LAB-Processed CaP-coated surface exhibited apatite-forming ability in SBF. Conclusions LAB Process is effective for CaP coating on light-cured dental composite resins and improving their osteoconductivity. Clinical significance The LAB Process is a potential new tool to create a cementum-like osteoconductive surface on dental composite resins.
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In Vitro and in Vivo Analysis of Mineralized Collagen-Based Sponges Prepared by a Plasma- and Precursor-Assisted Biomimetic Process.
ACS applied materials & interfaces, 2017Co-Authors: A. Joseph Nathanael, Ayako Oyane, Maki Nakamura, Ikuko Sakamaki, Erika Nishida, Yukimi Kanemoto, Hirofumi MiyajiAbstract:Three-dimensional (3D) porous scaffolds for supporting cell adhesion and growth play a vital role in tissue engineering applications. In the present study, three different collagen-based 3D sponges were functionalized by apatite coating. The sponges were coated with apatite on their outer and inner surfaces while retaining their interconnecting pores. To achieve this, we employed a vacuum degassing system in our plasma- and precursor-assisted Biomimetic Process using a supersaturated calcium phosphate solution. The resulting apatite-coated sponges (mineralized sponges) showed better cell adhesion properties in vitro for osteoblast-like MC3T3-E1 cells compared to that of uncoated sponges. The three mineralized sponges were implanted in the subcutaneous tissue of rats. Upon histological evaluation after 10 days, the mineralized sponges showed cell in-growth rates that were approximately 4-fold greater than those of the untreated sponges without any notable inflammatory reactions. As these sponges are compos...
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The mechanism underlying calcium phosphate precipitation on titanium via ultraviolet, visible, and near infrared laser-assisted Biomimetic Process
Journal of Physics D: Applied Physics, 2016Co-Authors: Moumita Mahanti, Maki Nakamura, Ikuko Sakamaki, Alexander Pyatenko, Kenji Koga, Ayako OyaneAbstract:We recently developed a rapid single-step calcium phosphate (CaP) precipitation technique on several substrates using a laser-assisted Biomimetic Process (LAB Process). In this Process, ultraviolet (UV, λ = 355 nm) pulsed laser irradiation has been applied to a substrate that is immersed in a supersaturated CaP solution. In the present study, the LAB Process for CaP precipitation on a titanium substrate was successfully expanded to include not only UV but also visible (VIS, λ = 532 nm) and near infrared (NIR, λ = 1064 nm) lasers. Surface heating and plasma-mediated surface reactions (micro-deformation, oxidization, photoexcitation, and wetting) generated by UV, VIS, or NIR lasers are considered to be involved in the CaP precipitation on the titanium surface in the LAB Process. The kinetics of these reactions and consequently of CaP precipitation were dependent on the laser wavelength and fluence. The higher laser fluence did not always accelerate CaP precipitation on the substrate; rather, it was found that an optimal range of fluence exists for each laser wavelength. These results suggest that for efficient CaP precipitation, a suitable laser wavelength should be selected according to the optical absorption properties of the substrate material and the laser fluence should also be adjusted to induce surface heating and plasma-mediated surface reactions that are favorable for CaP precipitation.
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Laser-assisted Biomimetic Process for surface functionalization of titanium metal
Colloids and Interface Science Communications, 2015Co-Authors: Ayako Oyane, Atsuo Ito, Maki Nakamura, Kenji Koga, Nao Matsuoka, Yoshiki Shimizu, Kenji Kawaguchi, Naoto Koshizaki, Yu Sogo, Hidero UnumaAbstract:Abstract Biomimetic calcium phosphate (CaP) precipitation Processes using supersaturated CaP solutions are useful in surface functionalization of biomedical materials. We applied our laser-assisted Biomimetic (LAB) Process to successfully achieve rapid single-step CaP precipitation on the surface of titanium metal, which is an important metallic biomaterial, by applying pulsed laser irradiation to the titanium substrate immersed in a supersaturated CaP solution. Precipitation occurred via the combined effect of laser surface modification and ambient heating. Moreover, we demonstrated immobilization of various contents of osteogenic substances (zinc and fibronectin components) on the titanium surface together with CaP by supplementing the CaP solution with these substances. The LAB Process is expected to be a facile and effective surface functionalization technique for titanium-based biomaterials to provide them with osteoconductivity because of CaP and stimulatory effects on bone formation due to osteogenic substances.
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Formation of Apatite Coatings on an Artificial Ligament Using a Plasma- and Precursor-Assisted Biomimetic Process
International journal of molecular sciences, 2013Co-Authors: Hirotaka Mutsuzaki, Yoshiro Yokoyama, Atsuo Ito, Ayako OyaneAbstract:A plasma- and precursor-assisted Biomimetic Process utilizing plasma and alternate dipping treatments was applied to a Leed-Keio artificial ligament to produce a thin coating of apatite in a supersaturated calcium phosphate solution. Following plasma surface modification, the specimen was alternately dipped in calcium and phosphate ion solutions three times (alternate dipping treatment) to create a precoating containing amorphous calcium phosphate (ACP) which is an apatite precursor. To grow an apatite layer on the ACP precoating, the ACP-precoated specimen was immersed for 24 h in a simulated body fluid with ion concentrations approximately equal to those in human blood plasma. The plasma surface modification was necessary to create an adequate apatite coating and to improve the coating adhesion depending on the plasma power density. The apatite coating prepared using the optimized conditions formed a thin-film that covered the entire surface of the artificial ligament. The resulting apatite-coated artificial ligament should exhibit improved osseointegration within the bone tunnel and possesses great potential for use in ligament reconstructions.
Darning Zhang - One of the best experts on this subject based on the ideXlab platform.
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fabrication of fibrous poly butylene succinate wollastonite apatite composite scaffolds by electrospinning and Biomimetic Process
Journal of Materials Science: Materials in Medicine, 2008Co-Authors: Darning Zhang, Jiang Chang, Yi ZengAbstract:In this paper, a novel kind of Poly(butylene succinate) (PBSU) /wollastonite/apatite composite scaffold was fabricated via electrospinning and Biomimetic Process. Pure PBSU scaffold and composite scaffolds with 12.5 wt% and 25 wt% wollastonite were firstly fabricated by electrospinning. SEM micrographs showed that all the electrospun scaffolds had homogeneous fibrous structures with interconnected pores and randomly oriented ultrafine fibers. The composite scaffolds were then surface modified using a Biomimetic Process. SEM and XRD results showed that apatite could deposit on the surfaces of the composite fibers after incubation in SBF and a novel fibrous structure with microspheres composed of worm-like apatite on composite fibers was formed. Incubation time and wollastonite content were found to influence the morphology of the scaffolds during the Biomimetic Process obviously. Both the amount and the size of the microspheres on the composite scaffolds increased with increased incubation time. After a certain incubation time, microspheres formed on the composite fibers with less wollastonite had a relatively larger size. Therefore, the microstructure of the composite scaffolds could be adjusted by controlling the wollastonite content and the incubation time. All of these results suggest that it is an effective approach to fabricate PBSU/wollastonite/apatite fibrous composite scaffolds with different material content and controllable microstructure for bone tissue engineering.
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Fabrication of fibrous poly(butylene succinate)/wollastonite/apatite composite scaffolds by electrospinning and Biomimetic Process
Journal of materials science. Materials in medicine, 2007Co-Authors: Darning Zhang, Jiang Chang, Yi ZengAbstract:In this paper, a novel kind of Poly(butylene succinate) (PBSU) /wollastonite/apatite composite scaffold was fabricated via electrospinning and Biomimetic Process. Pure PBSU scaffold and composite scaffolds with 12.5 wt% and 25 wt% wollastonite were firstly fabricated by electrospinning. SEM micrographs showed that all the electrospun scaffolds had homogeneous fibrous structures with interconnected pores and randomly oriented ultrafine fibers. The composite scaffolds were then surface modified using a Biomimetic Process. SEM and XRD results showed that apatite could deposit on the surfaces of the composite fibers after incubation in SBF and a novel fibrous structure with microspheres composed of worm-like apatite on composite fibers was formed. Incubation time and wollastonite content were found to influence the morphology of the scaffolds during the Biomimetic Process obviously. Both the amount and the size of the microspheres on the composite scaffolds increased with increased incubation time. After a certain incubation time, microspheres formed on the composite fibers with less wollastonite had a relatively larger size. Therefore, the microstructure of the composite scaffolds could be adjusted by controlling the wollastonite content and the incubation time. All of these results suggest that it is an effective approach to fabricate PBSU/wollastonite/apatite fibrous composite scaffolds with different material content and controllable microstructure for bone tissue engineering.