Papers by Author: Katsuya Kato

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Authors: Takao Saito, Hikoshiro Hayashi, K. Uoe, Takashi Kizuki, Kay Teraoka, Katsuya Kato, Yoshiyuki Yokogawa
Abstract: Our experiments of mouse osteoblast-like MC3T3-E1 cells cultured on a glass substrate showed that as surface roughness of a substrate increased, cell proliferation, cell differentiation and subsequent mineralization were reduced.
Authors: Takao Saito, Hikoshiro Hayashi, Tetsuya Kameyama, Katsuya Kato
Abstract: MC3T3-E1 mouse osteoblast-like cells were seeded at high cell density to form confluent monolayer on rough surfaced culture substrates. Osteoblastic gene and protein expressions and matrix mineralization were investigated to clarify the effect of surface roughness on differentiation of MC3T3-E1 cells.
Authors: Ryouichi Hikosaka, Fukue Nagata, Masahiro Tomita, Katsuya Kato
Abstract: Deoxyribonucleic acid (DNA) adsorption onto particles has applications in biosensors, separation methods, and gene delivery. Mesoporous silica (MPS), which exhibits a high surface area and large pore volume, is used in these applications because its pore size is easily controlled and its surface functional groups are easily exchanged. In this study, three types of MPSs with different pore sizes (2.4, 5.6, and 11.8 nm) were functionalized with different aminosilane coupling reagents and the effects of the MPS pore size and surface functional groups on DNA adsorption were evaluated. As the pore size of MPS increased, MPSs with diethylenetriamine (–3NH2) adsorbed higher amounts of DNA, whereas MPSs with hexylenediamine groups (–2HNH2) adsorbed lower amounts of DNA. Moreover, the fitting of DNA adsorption equilibrium data to Langmuir and Freundlich isotherm models was investigated.
Authors: Shota Watanabe, Fukue Nagata, Tatsuya Miyajima, Makoto Sakurai, Aoi Suzuki, Katsuya Kato
Abstract: Natural bone is a complex material with well-designed architecture. To achieve successful bone integration and regeneration, the constituent and structure of bone-repairing scaffolds need to be flexible and biocompatible. HAp, as the main composition of bone minerals, has excellent biocompatibility, while CMC comprised of a three-dimensional network were high flexibility. Therefore, CMC/HAp composite have been attracted attention due to the development of bone tissue engineering. In this work, carboxymethyl cellulose (CMC)/hydroxyapatite (Ca10(PO4)6(OH)2; HAp) composite have been developed as three-dimensional scaffold for bone tissue engineering. Scanning electron microscopy revealed that the CMC/HAp composite have sheet-like structure. The amount of precipitated HAp of CMC/HAp composite was investigated using Thermogravimetric analysis. The amount of precipitated HAp in products prepared with 100 mg CMC was 49.8 wt%, while the amount of precipitated HAp in products prepared with 1000 mg CMC was 22.3 wt%. These results revealed that the amount of precipitated HAp in CMC/HAp composite was affected by CMC amount as prepared.
Authors: Sindhu Seelan, Katsuya Kato, Yoshiyuki Yokogawa
Abstract: Mesoporous silica with 5~10 nm pore size was coated over recycled ceramic, prepared from lake sludge, with pore size 100-200μm. The mesoporous silica coated ceramic was characterized by XRD, N2 sorption, SEM and TEM. The results clearly showed the formation of mesoporous coating on the macroporous ceramics. These ceramics with the mesoporous coating are specially suitable for stabilization of enzymes. The mesopore stabilized enzymes are recyclable catalysts and showed comparable performance with the free enzyme.
Authors: Chiharu Tamura, Makoto Sakurai, Katsuya Kato
Abstract: Calcium phosphate (CaP) material has been used successfully for protein delivery. In the present work, our aim is the preparation of CaP combined with peptide and protein, and is the evaluation of pH-sensitive drug release ability. Protein used as the model drug was fluorescein isothiocyanate-bovine serum albumin (FITC-BSA). All compounds synthesized were low crystalline hydroxyapatite (HAp). The result of zeta potential indicated that incorporation of peptide in HAp could be changed the surface charge of particle. The CaP-BSA and CaP-BSA-pLys [Poly-L-lysine (pLys) was added to CaP composite.] were-23.1 mV and-12.0 mV, respectively. The ratio of protein release and dissolved Ca ion were measured by soaking CaP-peptide composites under various pH (pH 7.4, pH 6 and pH 5) conditions. BSA was released from CaP-BSA-pLys at only pH 5, not at pH 7.4 and pH 6.
Authors: Toshio Nagasaki, Fukue Nagata, Makoto Sakurai, Katsuya Kato
Abstract: The surface structure of Hydroxyapatite (HAp) particles during hydrothermal synthesis and their protein adsorption behavior was investigated. The HAp particles were prepared by mixing calcium acetate solution and diammonium hydrogen phosphate solution by hydrothermal synthesis. When the temperature of mixture were heated up to 120°C, 150°C and 180°C, the HAp particles were collected during hydrothermal synthesis. The adsorption properties of proteins onto HAp were studied using three types of proteins: bovine serum albumin (BSA), myoglobin (MGB) and lysozyme (LSZ). Surface analysis by BET revealed that their pore volumes were decreased by increasing synthesis temperature. The adsorbed amount of BSA and LSZ per unit milligrams showed no obvious difference in all of the HAp particles prepared with synthesis temperature. In contrast, the amount of MGB adsorbed onto HAp particles synthesized at 120°C, 150°, and 180°C shows the decreasing with an increasing synthesis temperature. This result suggests that the adsorbed amount of MGB was decreased by decreasing pore volume of HAp particles.
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