Papers by Author: Masanori Kikuchi

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Authors: Masanori Kikuchi, Atsushi Irie
Abstract: Osteoclast differentiation of bone marrow cells on hydroxyapatite/collagen self-organized bone-like nanocomposite (HAp/Col) disk in vitro was evaluated by coculture of mouse bone marrow cells with mouse osteoblasts with or without addition of osteoclastic inducers, 1,25-Dihydroxyvitamin D3 and 1 µM prostaglandin E2. Dentine slice and tissue culture polystyrene were used as controls. Good osteoclastic differentiation at day 7 were observed among the bone marrow cells cultured on the HAp /Col disk and controls with osteoclastic inducers. On the contrary, osteoclastic differentiation was observed only for marrow cells cultured on the HAp/Col disk. Nano- and micro- structures as well as chemical and mechanical properties have a potential to control cell differentiation.
449
Authors: Masanori Kikuchi, M. Tanaka
Abstract: Biomaterials Center is composed of five groups and collaborate each other to examine interdisciplinary fields of biomaterials. In the ceramics-based biomaterials research, we have been developing three novel bone regeneration materials, i.e., high-porosity hydroxyapatite (HAp) ceramics with high-strength, guided bone regeneration (GBR) membranes and bone-like nanocomposite composed of HAp and collagen. The GBR membrane composed of β-tricalcium phosphate and biodegradable copolymer of lactide, glycolide and ε-caprolactone has thermoplastic, pH auto-adjustment and enough mechanical property to protect an invasion of surrounding tissues. With the membrane, bone defect up to 20 × 10 × 10 mm3 in length in mandibles and segmental bone defect up to 20 mm in length in tibiae of beagles are regenerated without any additional bone fillers or cell transplantations. The bone-like nanocomposite is synthesized by a co-precipitation of HAp and collagen via their self-organization. The dense composite has a half to quarter mechanical strength (40 MPa) to cortical bone and the porous one demonstrates sponge-like viscoelasticity. The composites implanted into bone are incorporated into bone remodeling metabolism like as autogenous bone graft, i.e., they are resorbed by osteolasts followed by osteogenesis by osteoblasts.
277
Authors: Yoshihisa Koyama, Masanori Kikuchi, Shigeo Tanaka, M. Tanaka, Kazuo Takakuda
Abstract: In the treatment based on Guided Bone Regeneration method (GBR), membranes are necessary to cover bone defects and prevent the invasion of surrounding soft tissues. In spite of the potential usefulness of GBR method, no appropriate materials for the membrane have been developed and this method is not utilized frequently in common clinical practice. Here we developed materials such as a composite of β-tricalcium phosphate (β-TCP) and copolymer of L-lactide, glycolide and ε-caplolactone (PLGC), and designed the novel GBR membranes with ideal mechanical properties. The materials had good biocompatibility, and the membrane had sufficient strength although their thickness was as thin as 200 μm. The membranes were applied to large bone defects created in canine mandibular bones, and significant enhancement in bone regeneration was demonstrated.
258
Authors: Subhadip Bodhak, Masanori Kikuchi, Ayako Oyane, Yu Sogo, Hideo Tsurushima, Atsuo Ito
Abstract: Calcium phosphate (CaP) coating is an effective technique for surface functionalization of biomaterials. The objective of our research is to prepare calcium phosphate (CaP) coatings on a hydroxyapatite/collagen (HAp/Col) nanocomposite and subsequently provide it with gene delivery function through the immobilization of DNA in the coating. We have specifically selected the HAp/Col nanocomposite since it has the high potential as bone substitutes due to its similar composition, nanostructure, and biological properties to those of human bone. CaP coatings consisting of different sized particles were prepared on the HAp/Col nanocomposite membrane by immersing it in supersaturaterd CaP solutions (so-called RKM solutions) with the varied Ca and P concentration levels. We immobilized DNA in the CaP coatings together with lipid and fibronectin by supplementing DNA, lipid, and fibronectin to the RKM solutions (DLF-RKM solutions). Gene transfer capability of the resulting HAp/Col nanocomposite membrane was improved with decreasing concentration level of the DLF-RKM solution. It was confirmed that the present CaP coating technique was effective in providing the HAp/Col nanocomposite membrane with gene transfer capability and that the Ca and P concentration level of the DLF-RKM solution was a controlling factor affecting the gene transfer efficiency.
490
Authors: Masanori Kikuchi
Abstract: International standard for test method on cell migration into a scaffold is one of the important things to evaluate the scaffold. The "cell migration" ability can divide into two parts. One is infiltration of cell suspension before in vitro cell culture on the scaffold. Another is migration of adherent cells from the edge of scaffold. The latter one could be closely related to cell/tissue migration into the scaffold when it is implanted into bone. Thus, in the present study, the cell migration ability was evaluated toward standardization of in vitro evaluation method for in vivo cell/tissue migration ability using several bioactive ceramics and composites including commercially available materials. The specimen 5 mm in diameter was placed on confluent MG63 cell layer. After 3 days incubation, the specimen was harvested, fixed and divided into two parts. Inside and outside of the scaffold were stained by Giemsa and observed by optical microscopy. In addition, the same specimen was critical point dried and observed with scanning electron microscope (SEM). From microscopic observation, MG63 cells migrated to pore walls of the specimen as well as a sidewall. Maximum migration distances were different among specimens and seemed to depend on pore structure and size as well as porosity. Similar behaviors were observed with SEM.Even relations between this test method and in vivo cell/tissue migration have not been evaluated, this test method is potentially a good method for testing cell migration ability of porous bioactive ceramics as well as other porous scaffold materials.
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Authors: Teruaki Yoshida, Ikko Mizuno, Masanori Kikuchi, Yoshihisa Koyama, Kazuo Takakuda
Abstract: The bone-like self-organized hydroxyapatite/collagen (HAp/Col) nanocomposite sponge was prepared from HAp/Col nanocomposite fibers. We analyzed osteogenic activity of human osteoblastic MG63 cells in the HAp/Col sponge under pressure/perfusion culture. Collagen (Col) sponge was used as a control. The MG63 cells were attached well and showed good proliferation in the HAp/Col sponge. The total DNA content in the HAp/Col sponge was approximately 1.8 times greater than that in the Col sponge at 21 days. The MG63 cells showed good osteogenic gene expression in the HAp/Col sponge by reverse transcription-polymerase chain reaction analysis. These result suggested that HAp/Col sponge can be useful for bone tissue engineering scaffold materials.
1079
Authors: Masanori Kikuchi, Tsunemasa Taguchi, Hiroshi Matsumoto, M. Tanaka, Kazuo Takakuda
449
Authors: Yu Lin Li, Masanori Kikuchi
Abstract: Biocompatible and water-soluble fibers (sodium carboxymethyl cellulose (CMC)) were fabricated via a wet-spinning method. The CMC fibers/ polymethyl methacrylate (PMMA) mixtures and CMC fibers/Poly (L-lactide-co-glycolide-co- -caprolactone) (PLGC) mixtures were prepared by a heat-kneading method. For CMC fibers/PMMA, after removal of the CMC fibers from the mixtures, the interconnected porous scaffolds with porosity from 27.79 % to 60.98 % (volume percent) were obtained. For CMC fibers/PLGC, the interconnected porous scaffolds with porosity 38.55 % and 76.83 % (volume percent) were prepared. The solid CMC fibers/PLGC mixtures had the higher ultimate tensile strength and Young, s modulus than those of porous PLGC scaffolds.
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