Bioceramics 17

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Authors: A.L. Oliveira, M.I. Santos, A.A. Pedro, Rui L. Reis
Abstract: In the present study sodium clodronate, a well known therapeutic agent from the family of bisphosphonates (BP) was incorporated in an apatite coating, previously formed on the surface of a starch based biomaterial by a sodium silicate methodology, as a strategy to develop a site-specific drug delivery system for bone tissue regeneration. The effects on the resulting apatite coatings were evaluated in terms of morphology, chemistry and structure. As a preliminary approach, this first study aimed at evaluating also the effects of this BP on the viability, growth and function of a human osteoblast cell line, since there is still little information available on the interaction between BPs and this type of cells.
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Authors: Jun Yao, Shula Radin, Gwendolen Reilly, Phoebe S. Leboy, Paul Ducheyne
Abstract: A previous study demonstrated that the incorporation of bioactive glass (BG) into poly (lactic-co-glycolic acid) (PLGA) can promote the osteoblastic differentiation of marrow stromal cells (MSC) on PLGA by forming a calcium phosphate rich layer on its surface. To further understand the mechanisms underlying the osteogenic effect of PLGA-BG composite scaffolds, we tested whether solution-mediated factors derived from composite scaffolds/hybrids can promote osteogenesis of marrow stromal cells. The dissolution product from PLGA-30%BG scaffold stimulated osteogenesis of MSC, as was confirmed by increased mRNA expression of osteoblastic markers such as osteocalcin (OCN), alkaline phosphatase (ALP), and bone sialoprotein (BSP). The three-dimensional structure of the scaffolds may contribute to the production of cell derived factors which promoted distant MSC differentiation. Thus PLGA-BG composites demonstrates significant potential as a bone replacement material.
619
Authors: Julian R. Jones, Archana Vats, Ioan Notingher, Julie E. Gough, Neil S. Tolley, Julia M. Polak, Larry L. Hench
Abstract: Septal cartilage is widely used for the repair of soft tissue defects in the head, neck and nose. Tissue Engineering techniques are being investigated to create cartilage in vitro by seeding appropriate cells on resorbable scaffolds. In this study, human chondrocytes were cultured on macroporous bioactive glass foam scaffolds. The aim was to investigate how Raman spectroscopy could be used as a non-invasive technique to monitor the response of chondrocytes to a 3D scaffold in real time. The spectra were compared to scanning electron microscope (SEM) micrographs and immunohistochemistry results.
623
Authors: Meera Q. Arumugam, Roger A. Brooks, Neil Rushton, William Bonfield
Abstract: The object of this study was to investigate methods of seeding cells onto porous hydroxyapatite granules with the aim of optimising cell attachment. Two cells types were used; an osteosarcoma cell line, MG63, and human osteoblasts (HOBs) isolated from trabecular bone. Several conditions were investigated to determine their effect on cell attachment. These included varying the initial seeding concentration, pre-adsorption of the granules with the adhesion protein fibronectin and the use of mechanical agitation. Human osteoblasts and MG63 osteosarcoma cells attached to both dense and porous HA granules but with a low seeding efficiency while seeding was not significantly improved by pre-coating scaffolds with fibronectin or by introducing fluid flow.
627
Authors: Suk Young Kim, Chang Kuk You, Jae Ho Jeong, Eui Kyun Park, Shin Yoon Kim, Hong In Shin
Abstract: As a part of the efforts to develop a suitable scaffold optimizing bone regeneration that has similar physical properties to bone, we modified calcium metaphosphate (CMP) ceramics with K2O and evaluated their efficiency as a scaffold for tissue engineered bone tissue regeneration. Macroporous CMP ceramics modified by incorporation of 5% K2O to improve biodegradability were prepared to have 250 and 450 µm average pore sizes, respectively. The modified CMP ceramics were cultured with mouse primary calvarial osteoblastic cells in osteogenic media for 2 weeks and these cell-CMP ceramic constructs with or without Emdogain treatment were implanted in the SCID mice subcutaneous pouches. After 1, 2, and 3 weeks, the degree of ectopic bone formation was evaluated. The modified macroporous CMP ceramic-cell constructs treated with Emdogain induced ectopic bone formation, whereas the modified CMP ceramic-cell constructs without Emdogain treatment induced no ectopic bone formation. This result suggests that the Emdogain treatment on cell-scaffold constructs for tissue engineered bone regeneration may be effective for osteogenic activation of attached cells.
631
Authors: B.V. Sampaio, G. Göller, Faik N. Oktar, Patricia Valério, Alfredo Goes, M. Fatima Leite
Abstract: Two (45.5 wt % P2O5, 54.5 wt% CaO) and three (45 wt % P2O5, 28 wt% CaO, 27wt% Na2O) oxide glasses, sinterizing at 1200 and 1300oC[2] showed an increase on cell viability and proliferation.
635
Authors: B.V. Sampaio, G. Göller, Faik N. Oktar, Patricia Valério, Alfredo Goes, M. Fatima Leite
Abstract: Titanium reinforced with hydroxyapatite (TiHA) prepared using 15% of titanium and 3 different sinterizing temperatures 1100, 1200 and 1300 oC showed a significant increase in cell proliferation, when compared to the control.
639
Authors: Elizabeth C. Kolos, Andrew Ruys, Ramin Rohanizadeh, M.M. Muir, Greg J. Roger
Abstract: The aim of this study was to fabricate a micro-tube scaffold using a biomimetic method (immersion in Simulated Body Fluid, SBF) to coat apatite on cotton fibres. The cotton fibres were first pre-treated using a phosphorylation technique and then apatite crystals were deposited on the fibres by immersing in SBF. Micro-tubes were then formed by burning out the cotton fibres at various temperatures between 950-1250°C. The scaffolds were fabricated by compaction of the micro-tubes in a mould. The compacted micro-tubes were then sintered at various temperatures between 900-1200°C. The biocompatibility and the effects of the surface morphology of scaffolds on cell coverage and proliferation were determined using osteoblast cell culture. The results showed that these scaddolds were biocompatible and able to support cell growth. Future studies include animal studies for biomimetic tissue scaffold as a bone filler substitute material.
643
Authors: Jean Christophe Fricain, L. Pothuaud, M.C. Durrieu, S. Pallu, Reiner Bareille, M. Renard, J. Jeanfils, M. Dard, J. Amédée
Abstract: The aim of this study was to evaluate the in vivo effects of the grafting of cyclo- DfKRG on the early phase of integration of biomaterials made with macroporous hydroxyapatite/b-tricalcium phosphate colonized with autologous bone marrow stromal cells. Non-grafted (-RGD) and grafted (+RGD) biomaterials were implanted in both femoral condyles of rabbits for 2 and 4 weeks. Two weeks after implantation, the global bone formation was higher with +RGD samples (p=0.02). There remained no significant difference 4 weeks after implantation. In conclusion, grafting of cyclo-DfKRG peptide on materials could promote cell colonization and improve osteoconduction during the first stage of the bone cicatrization process.
647
Authors: Jin Iida, Takafumi Yoshikawa, Kazuhide Miyazaki, Noriko Okumura, Yoshinori Takakura
Abstract: Osseous tissue can be formed by culturing marrow cells with compounds such as dexamethasone and that a bone matrix cultured in this manner possesses BMP activity. We have reported that artificial bones with a high level of osteogenic potential can be prepared by culturing artificial bone materials with cultured osseous tissue. Here, in an attempt to develop activated cultured bone constructs with even greater osteogenic potential, the effects of the female hormone estriol on osteogenesis were investigated. Bone marrow cells were collected from the femur shafts of 7-week-old male Fischer rats, and subjected to primary and secondary cultures. During secondary culture with or without dexamethasone (Dx), 10-5, 10-6, 10-7, 10-8 or 10-9 M of estriol was added to a standard culture medium containing ascorbic acid and β-glycerophosphosphate. The alkaline phosphatase(ALP) activity and Ca levels were measured and statistically analyzed. There was a significant difference in ALP activity between the control group and the estriol groups, and ALP activity was the highest in the 10-7 and 10-8 M groups, being about 2.5 times higher than in the control group. Similar results were seen for Ca levels. Furthermore, in vivo study showed10-7M-estriol-treated-cultured bone/ceramic construct has significant high osteogenic potential when it is grafted into in vivo. Estriol has been reported to increase bone mass, and the results of the present study suggest that the osteogenic potential of cultured bone constructs can be more than doubled by adjusting the concentration of estriol in bone marrow cell culture. Therefore, the use of estriol may be able to facilitate osteogenesis in bone regeneration therapy.
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