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Ceramic Scaffolds (ceramic + scaffold)
Selected AbstractsMonodisperse Mesoporous Silica Spheres Inside a Bioactive Macroporous Glass,Ceramic Scaffold,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Renato Mortera In the field of bone tissue engineering, monosized MCM-41 spheres have been incorporated inside a bioactive glass,ceramic macroporous scaffold belonging to the SiO2CaOK2O (SCK) system so obtaining a multiscale hierarchical composite. The MCM-41-SCK system was prepared by dipping the glass,ceramic scaffold into the MCM-41 synthesis solution and was characterized by means of XRD, micro-XRD, N2 sorption and scanning electron microscopy. The MCM-41 spheres inside the scaffold are highly uniform in diameter, as those synthesized in powder form. The adsorption capacity of the composite toward ibuprofen is three times higher than that of the MCM-41-free scaffold, because of the presence of the ordered mesoporous silica. Also the release behavior in SBF at 37,°C is strongly affected by the presence of MCM-41 inside the scaffold macropores. [source] Regeneration of large bone defects in sheep using bone marrow stromal cellsJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 5 2008P. Giannoni Abstract Bone repair was addressed in a critical-sized defect model in sheep, combining a ceramic biomaterial and mesenchymal progenitor cells. The defects in the tibial mid-diaphysis were treated with autologous bone or with a silicon-stabilized tricalcium phosphate biomaterial, implemented or not by the addition of expanded bone marrow stromal cells. An internal locking compression plate and an external fixator were applied for stabilization. Radiographies were taken during the 8 months follow-up: the pixel grey levels of the lesion areas were determined to evaluate the repair process radiologically. Microradiography, histology and vascular density tests were performed. The autologous bone-treated group performed best, as assessed radiologically, within 20,24 weeks after surgery. Very limited healing was detected in the other experimental group: a partial bone deposition occurred at the periphery of the bony stumps only in the cell-seeded scaffolds. Interestingly, this effect ended within 20,24 weeks, as for the autologous bone, suggesting similar kinetics of the repair processes involved. Moreover, bone deposition was located where a significant reduction of the ceramic scaffold was detected. Faxitron microradiography and histology data confirmed these results. Vascular density analysis evidenced that cell-seeded scaffolds supported an increased vascular ingrowth. Thus, the interactions with the proper microenvironment and the oxygen and nutrient supply in the inner part of the constructs seem fundamental to initiate scaffold substitution and to improve cell performance in tissue-engineered approaches to bone repair. Copyright © 2008 John Wiley & Sons, Ltd. [source] In vivo bioluminescence imaging study to monitor ectopic bone formation by luciferase gene marked mesenchymal stem cellsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2008Cristina Olivo Abstract Mesenchymal stem cells (MSCs) represent a powerful tool for applications in regenerative medicine. In this study, we used in vivo bioluminescence imaging to noninvasively investigate the fate and the contribution to bone formation of adult MSCs in tissue engineered constructs. Goat MSCs expressing GFP-luciferase were seeded on ceramic scaffolds and implanted subcutaneously in immune-deficient mice. The constructs were monitored weekly with bioluminescence imaging and were retrieved after 7 weeks to quantify bone formation by histomorphometry. With increasing amounts of seeded MSCs (from 0 to 1,×,106 MSC/scaffold), a cell-dose related increase in bioluminescence was observed at all time points, correlating with increased bone formation at 7 weeks. To investigate the relevance of MSC proliferation to bone deposition, cell-seeded scaffolds were irradiated. The irradiated cells were functional with respect to oxygen consumption but no increase in bioluminescence was observed in vivo, and only minimal bone was produced. Proliferating MSCs are likely required for initiation of bone formation in tissue engineered constructs in vivo. Bioluminescence is a useful tool to monitor cellular responses and predict bone formation in vivo. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:901,909, 2008 [source] Genetic marking with the ,LNGFR-gene for tracing goat cells in bone tissue engineering,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2004M. C. Kruyt Abstract The use of bone marrow derived stromal cells (BMSC's) for bone tissue engineering has gained much attention as an alternative for autologous bone grafting. Little is known however, about the survival and differentiation of the cells, especially in the clinical application. The aim of this study was to develop a method to trace goat BMSC's in vivo. We investigated retroviral genetic marking, which allows stable expression of the label with cell division. Goat BMSC's were subjected to an amphotropic envelope containing a MoMuLV-based vector expressing the human low affinity nerve growth factor receptor (,LNGFR). Labeling efficiency and effect on the cells were analyzed. Furthermore, transduced cells were seeded onto porous ceramic scaffolds, implanted subcutaneously in nude mice and examined after successive implantation periods. Flow cytometry indicated a transduction efficiency of 40,60%. Immunohistochemistry showed survival and subsequent bone formation of the gene-marked cells in vivo. Besides, marked cells were also found in cartilage and fibrous tissue. These findings indicate the maintenance of the precursor phenotype following gene transfer as well as the ability of the gene to be expressed following differentiation. We conclude that retroviral gene marking with ,LNGFR is applicable to trace goat BMSC's in bone tissue engineering research. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Bone tissue engineering in a critical size defect compared to ectopic implantations in the goatJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2004Moyo C. Kruyt Abstract Since the application of the autologous bone graft, the need for an alternative has been recognized. Tissue engineering (TE) of bone by combining bone marrow stromal cells (BMSCs) with a porous scaffold, is considered a promising technique. In this study we investigated the potential of tissue engineered bone to heal a critical sized defect in the goat. Orthotopic bone formation was compared to ectopic bone formation in comparable constructs. TE constructs were prepared from goat BMSCs and porous biphasic calcium phosphate ceramic scaffolds. These constructs and scaffolds without cells were implanted paired in critical sized iliac wing defects. Comparable samples were implanted intramuscularly. After 9 (n = 7) and 12 (n = 8) weeks implantation, the samples were analyzed histomorphometrically. After 9-weeks implantation in the iliac wing defect, significantly more bone apposition was found in the TE condition. After 12 weeks, the defects were almost completely filled with bone, but no significant advantage of TE was determined anymore. This contrasted with the intramuscular samples where TE implants showed significantly more bone at both time points. In conclusion, bone TE is feasible in critical sized defects. However, when appropriate osteoconductive/inductive materials are applied the effect of cell seeding may be temporary. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Bone Response Inside Free-Form Fabricated Macroporous Hydroxyapatite Scaffolds with and without an Open MicroporosityCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2007Johan Malmström DDS ABSTRACT Background:, The technique of free-form fabrication enables the production of controlled macroporous geometry inside ceramic scaffolds. Using scaffolds with identical macropore design makes it possible to study a relevant biological response linked to other specific changes of the material. Purpose:, This study investigates the role of open micropores in hydroxyapatite (HA) scaffold during early bone healing to quantitatively ascertain whether microporosity in otherwise identical macroporous HA scaffolds can influence the bone response in rabbit tibia and femur at 6 weeks. Materials and Methods:, HA scaffolds (Ø: 3.8 mm) with and without microporosity were randomly installed in both cortical and trabecular bone sites of New Zealand White rabbits. The animals were sacrificed 6 weeks after surgery. Ground sections obtained from en bloc tissues containing scaffold and recipient bone were subjected to histological evaluation and histomorphometric analysis. Results:, Microscopy showed elevated amounts of bone ingrowth and bone contact inside the microporous HA (mHA) group as compared with non-mHA. Conclusion:, The current study indicates that the presence of open scaffold microporosity in HA, as determined by the fabrication process, enhances the ability of ceramic scaffolds to promote bone ingrowth and bone contact. [source] | ||||||||||