Authors: Subhadip Bodhak, Masanori Kikuchi, Ayako Oyane, Yu Sogo, Hideo Tsurushima, Atsuo Ito
Abstract: Hydroxyapatite/collagen (HAp/Col) nanocomposites with bone-like self-organized nanostructure show excellent bioactivity in vivo. However, they show quite high absorbability for cationic ions and lower culture medium ionic concentrations which adversely affects bone cell proliferation and osteogenic differentiation in in vitro cell culture condition. To address this limitation, in this study we have supplemented Ca2+ and Mg2+ ions to the HAp/Col nanocomposite membrane sample prior to cell culture to improve it’s in vitro biological properties. The HAp/Col nanocomposite membrane samples were fabricated by the simultaneous titration method using Ca(OH)2, type-I atelocollagen and H3PO4 as starting precursor materials. Prior to in vitro cell culture experiments, the HAp/Col samples were pretreated with Ca2+ and/or Mg2+ ions by immersing in 10 ml of 20 mM CaCl2 solution, 20 mM MgCl2 solution, or a solution containing 20 mM CaCl2 and 20 mM MgCl2 for 7 days. In vitro bone cell-material interactions on the pretreated and untreated HAp/Col samples were studied by culturing MC3T3-E1 cells up to 7 days. Enhanced bone cell proliferation was found on all the pretreated HAp/col samples as confirmed by the CCK-8 assay. Interestingly, the HAp/Col samples pretreated with both Ca2+ and Mg2+ ions showed the maximum viable bone cell density.
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Authors: Conor T. Buckley, K.U. O’Kelly
Abstract: Tissue-engineering scaffold-based strategies have suffered from limited cell depth
viability when cultured in vitro, with viable cells existing within the outer 250-500μm from the
fluid-scaffold interface. This is primarily believed to be due to the lack of nutrient delivery into and
waste removal from the inner regions of the scaffold construct. Other issues associated with porous
scaffolds involve poor seeding efficiencies and limited cell penetration resulting in heterogeneous
cellular distributions. This work focuses on the development a novel hydroxyapatite multi-domain
porous scaffold architecture (i.e. a scaffold providing a discrete domain for cell occupancy and a
separate domain for nutrient delivery) with the specific objectives of embodying in one scaffold the
structures required to optimise cell seeding, cell proliferation and migration and potentially to
facilitate vascularisation once implanted in vivo. This paper presents the development of the multidomain
architecture and preliminary results on cell viability which show a significant improvement
in cell viability in the scaffold interiors.
931
Authors: Yu Sogo, Yuusuke Ishikawa, Nao Kondo, Eiji Uchimura, Ayako Oyane, Tadao Ohno, Atsuo Ito, Atsushi Yamazaki
Abstract: Fibronectin (FN) and type I collagen (Col), which are kinds of extracelluar matrices, were coprecipitated with calcium phosphate to form a composite layer on a hydroxyapatite (HAP) ceramic using a supersaturated calcium phosphate solution (CP solution). The amounts of protein immobilized in the layers were determined to be 20.97±3.04 µg·cm-2 for FN, 5.26±0.19 µg·cm-2 for Col and 21.72±2.30 µg·cm-2 for simultaneously immobilized FN and Col. When osteoblastic
MC3T3-E1 cells were cultured on the HAP ceramics with the composite layer containing FN and/or Col, calcified tissue was formed through the activity of the cells. The result showed that the composite layer accelerated the differentiation of MC3T3-E1 to bone-forming cells. It is assumed that osteoblastic cells in alveolar bone migrated and differentiated on the surface of the tooth roots
when the artificial tooth roots were covered with the composite layer.
767
Authors: Akira Watazu, Kay Teraoka, Hirofumi Kido, Kae Okamatsu, Yoshiyuki Nagashima, M. Morita, Masanori Matsuura, Naobumi Saito
Abstract: Commercially pure titanium thin films were uniformly formed on inner surfaces of tissue culture dishes by DC sputtering method. Then, the thickness of the film was about 30nm and the films were thin titanium oxide layer on commercially pure titanium. MC3T3-E1 cells were normally cultured on the dishes. Then, The films on the dishes were not broken and did not decompose. After 24 hours, observations of the sample from the direction of the cells' bottom surfaces adhered the
titanium oxide on the commercially pure titanium film by an inverted optical microscope succeeded. Therefore, the new technique is useful for observations the interactions between titanium oxide and cells.
363
Authors: D.H. Lee, Dong Wook Han, B.J. Park, Hyun Sook Baek, K. Takatori, M. Aihara, Kazufumi Tsubaki, Jong Chul Park
Abstract: b-glucan, an immunomodulator, can selectively enhance the immunobiological
activities of neutrophils and macrophages without stimulating proinflammatory cytokine production. Biologic response modifiers, like beta-glucan, will modulate immunity, modify neoplastic disease and increase resistance to microbial challenge. Therefore, beta-glucan polymers can be applied in bone induction and regeneration model and have a possibility of association with bone morphogenetic protein (BMP) because of tissue-regenerative and antimicrobial effects of those polymers. In this report, we studied an E. coli expression system for BMP-7 production and the biological activities of b-glucan associated with BMP-7. The proliferation of MC3T3-E1 osteoblastic cells was enhanced by treatment with Aureobasidium b-glucan, while neither mushroom b-glucan nor barley b-glucan increased the cell proliferation. Mushroom b-glucan alone or associated with BMP-7 increased alkaline phosphatase (ALP) activity of MC3T3-E1 cells, one of the osteoblast phenotype markers, but the other b-glucans did not affect ALP activity
of the cells. In mineralization assay, a highly significant increase in nodular staining was observed in cultures treated with both mushroom and Aureobasidium b-glucans in the presence of BMP-7 compared with nontreated controls, while barley b-glucan showed a significant decrease in nodule number compared with cultures treated only with BMP-7.
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