Papers by Author: Hirotaka Maeda

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Authors: Y. Yamamoto, Hirotaka Maeda, H. Shibutani, H. Suzuki, O. Horiuchi
135
Authors: Hirotaka Maeda, Toshihiro Kasuga
Abstract: A new type of poly(lactic acid) (PLA)/calcium carbonates hybrid membrane incorporated with silicon, which is suggested to stimulate the formation of bones, was prepared using aminopropyltriethoxysilane (APTES) for bone repair materials. Carboxyl groups in PLA made a chemical bond with amino groups in APTES, resulting in the formation of the hybrid membrane. The membrane formed hydroxycarbonate apatite (HCA) on its surface after 3 days of soaking in simulated body fluid (SBF). X-ray energy dispersive spectroscopy showed the HCA layer includes Si with Ca and P. A result of osteoblast-like cellular proliferation on the substrates that the membrane coated with silicon-containing HCA had much higher cell-proliferation ability than the membrane.
239
Authors: Hirotaka Maeda, Toshihiro Kasuga, Masayuki Nogami
Abstract: Hydroxycarbonate apatite (HCA), which formed on a poly(lactic acid) (PLA) composite membrane containing vaterite or calcium chloride after soaking in simulated body fluid, was examined to clarify the importance of the ceramic phases in the composites. FT-IR spectra showed that the ratio of CO3/PO4 in the infrared adsorption bands of HCA formed on the PLA composite containing vaterite was much larger than that of HCA formed on the PLA composite containing calcium chloride. Substitution of carbonate ion in hydroxyapatite is believed to be strongly influenced by ceramic phases in the composites. The zeta potentials of HCA formed on the PLA composite containing vaterite or calcium chloride was -6 mV or -17 mV, respectively. The zeta potential may be influenced by the amount of carbonate ion in hydroxyapatite.
489
Authors: Akiko Obata, Hirotaka Maeda, Toshihiro Kasuga
Abstract: Silicon-doped calcium carbonate / poly (lactic acid) composites (Si-CCPC) were estimated in cellular biocompatibility with culture tests using osteoblast-like cells (MC3T3-E1) and mesenchymal stem cells (MSC). The cellular biocompatibility of Si-CCPC was enhanced by coating with bone-like hydroxycarbonate apatite (b-HA) formed by simulated body fluid immersion. The b-HA was formed on Si-CCPC after 3-days of immersion and closely bonded with Si-CCPC. Numerous MC3T3-E1 and MSC showed good adhesion on the b-HA with extending their lamellipodia. The number of adhering MC3T3-E1 on Si-CCPC coated with the b-HA was higher than that on Si-CCPC. The b-HA has excellent biocompatibility and silicon is regarded to stimulate osteoblast and bone formation in vivo and vitro. The b-HA containing silicon on Si-CCPCis expected to enhance the cellular adheresion, proliferation and differentiation.
1113
Authors: Hirotaka Maeda, Toshihiro Kasuga, Masayuki Nogami, Y. Hibino, K.I. Hata, M. Ueda, Y. Ota
163
Authors: Hirotaka Maeda, Toshihiro Kasuga, Masayuki Nogami, H. Kagami, K. Hata, M. Ueda
497
Authors: Hirotaka Maeda, Toshihiro Kasuga, Masayuki Nogami
533
Authors: Hirotaka Maeda, Noriko Miura, Toshihiro Kasuga, Masayuki Nogami
Abstract: Novel hollow spheres for bone fillers incorporating cells were prepared using composites consisting of poly(lactic acid) and calcium carbonates. An open channel of ~800 µm in diameter was easily formed using a chemical etching method to provide a pathway to the interior of the sphere. Cells could migrate through the open channel into the interior of the sphere. Bonelike apatite coating on the surface of the sphere was prepared by soaking in calcium chloride solution to supply excess Ca2+ ions on the surface and subsequently by soaking in simulated body fluid. The hollow spheres with an open channel may be one of the great potential candidates as novel bone fillers combined with a cell-delivery system.
301
Authors: Toshihiro Kasuga, Akiko Obata, Hirotaka Maeda, Larry L. Hench
Abstract: Calcium carbonate (vaterite)-containing poly(lactic acid) (PLA) composites (CCPCs) were prepared for novel biomaterials that are expected to exhibit high bioresorbability and osteoconductivity. CCPC containing 30% vaterite showed bending strengths of 40~50 MPa. 13C CP/MAS-NMR spectrum of CCPC suggested the formation of a bond between Ca2+ ion and COOgroup. The bond may play an important role in the improvement of the mechanical properties. On the surface of CCPC containing 30 % vaterite, ~10-μm-thick hydroxycarbonate apatite (HCA) formed after 1 day of soaking in SBF at 37oC. After 1-week incubation of human osteoblasts (HOBs) on the HCA-coated CCPC, numerous HOBs attached. The adhesion of cells on the composite was greater than that on PLA. After 3-week culture of HOBs on HA-coated CCPC, numerous bone nodules could be seen on the surface. CCPC is believed to be one of the most promising materials for bone repair. A novel CCPC containing polysiloxane was also prepared using aminopropyltriethoxysilane (APTES). Polysiloxane partially assembled in the membrane and a molecular chain of PLA was bonded at the end of an organic chain in APTES through the amide bond formed between carboxy groups in PLA and amino groups in APTES. The composite formed HA on its surface after 3 days of soaking in SBF. The HA layer included Si with Ca and P. The composite coated with silicon-containing HCA had higher cell-proliferation ability than that without HA. The existence of silicon-containing HCA may be apt to stimulate the proliferation.
617
Authors: Hirotaka Maeda, Toshihiro Kasuga, Larry L. Hench
Abstract: A novel poly(lactic acid) (PLA)/calcium carbonates hybrid membrane containing silica was prepared using aminopropyltriethoxysilane (APTES) for biodegradable bone guided regeneration. Carboxy groups in PLA made a chemical bond with amino groups in APTES, resulting in the formation of the hybrid membrane. The silica-hybridized PLA was an amorphous phase. The membrane formed hydroxycarbonate apatite (HCA) on its surface after 3 d of soaking in simulated body fluid (SBF). After soaking the membrane in SBF, almost no Si was present in SBF. X-ray energy dispersive spectroscopy showed the HCA layer includes Si with Ca and P. A result of osteoblast-like cellular proliferation on the membrane showed no cell-toxicity.
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