Technology and Health Care - Volume 15, issue 1

Authors: Lee, T. Clive | O'Brien, Fergal J.

Article Type: Editorial

DOI: 10.3233/THC-2007-15101

Citation: Technology and Health Care, vol. 15, no. 1, pp. 1-2, 2007

Authors: O'Brien, Fergal J. | Harley, Brendan A. | Waller, Mary A. | Yannas, Ioannis V. | Gibson, Lorna J. | Prendergast, Patrick J.

Article Type: Research Article

Abstract: The permeability of scaffolds and other three-dimensional constructs used for tissue engineering applications is important as it controls the diffusion of nutrients in and waste out of the scaffold as well as influencing the pressure fields within the construct. The objective of this study was to characterize the permeability/fluid mobility of collagen-GAG scaffolds as a function of pore size and compressive strain using both experimental and mathematical modeling techniques. Scaffolds containing four distinct mean pore sizes (151, 121, 110, 96 microns) were fabricated using a freeze-drying process. An experimental device was constructed to measure the permeability of the scaffold variants …at different levels of compressive strain (0, 14, 29 and 40% while a low-density open-cell foam cellular solids model utilizing a tetrakaidecahedral unit cell was used to accurately model the permeability of each scaffold variant at all level of applied strain. The results of both the experimental and the mathematical analysis revealed that scaffold permeability increases with increasing pore size and decreases with increasing compressive strain. The excellent comparison between experimentally measured and predicted scaffold permeability suggests that cellular solids modelling techniques can be utilized to predict scaffold permeability under a variety of physiological loading conditions as well as to predict the permeability of future scaffolds with a wide variety of pore microstructures. Show more

Keywords: Collagen, scaffold, tissue engineering, permeability, cell attachment

DOI: 10.3233/THC-2007-15102

Citation: Technology and Health Care, vol. 15, no. 1, pp. 3-17, 2007

Authors: Farrell, E. | Byrne, E.M. | Fischer, J. | O'Brien, F.J. | O'Connell, B.C. | Prendergast, P.J. | Campbell, V.A.

Article Type: Research Article

Abstract: Adult mesenchymal stem cells (MSCs) have the capability to differentiate along several lineages including those of bone, cartilage, tendon and muscle, thus offering huge potential for the field of tissue engineering. The purpose of this study was to characterise the differentiation capacity of rat MSCs cultured on standard plastic coverslips in 2 dimensions and on a novel collagen glycosaminoglycan scaffold in the presence of a standard combination of osteoinductive factors. Cells were cultured for 3, 7, 14 and 21 days and several markers of osteogenesis were analysed. While the initial response of the cells in 3-D seemed to be faster …than cells cultured in 2-D, as evidenced by collagen type I expression, later markers showed that osteogenic differentiation of MSCs took longer in the 3-D environment of the collagen GAG scaffold compared to standard 2-D culture conditions. Furthermore, it was shown that complete scaffold mineralisation could be evoked within a 6 week timeframe. This study further demonstrates the potential use of MSC-seeded collagen GAG scaffolds for bone tissue engineering applications. Show more

Keywords: Mesenchymal stem cell, osteogenesis, collagen glycosaminoglycan scaffold

DOI: 10.3233/THC-2007-15103

Citation: Technology and Health Care, vol. 15, no. 1, pp. 19-31, 2007

Authors: Fassina, L. | Visai, L. | De Angelis, M.G. Cusella | Benazzo, F. | Magenes, G.

Article Type: Research Article

Abstract: There is increasing interest in new biomaterials and new culture methods for bone tissue engineering, in order to produce, in vitro, living constructs able to integrate in the surrounding tissue. Using an electromagnetic bioreactor (magnetic field intensity, 2 mT; frequency, 75 Hz), we investigated the effects of electromagnetic stimulation on SAOS-2 human osteoblasts seeded onto a porous polyurethane. In comparison with control conditions, the electromagnetic stimulation caused higher cell proliferation, increased surface coating with decorin and type-I collagen, and higher calcium deposition. The immunolocalization of decorin and type-I collagen showed their colocalization in the cell-rich areas. The use of an …electromagnetic bioreactor aimed at obtaining the surface modification of the porous polyurethane in terms of cell colonization and coating with calcified matrix. The superficially modified biomaterial could be used, in clinical applications, as an implant for bone repair. Show more

Keywords: Electromagnetic stimulation, osteoblast, cell proliferation, extracellular matrix, decorin, type-I collagen, calcium, surface modification, biomimetics

DOI: 10.3233/THC-2007-15104

Citation: Technology and Health Care, vol. 15, no. 1, pp. 33-45, 2007

Authors: Pilliar, R.M. | Kandel, R.A. | Grynpas, M.D. | Zalzal, P. | Hurtig, M.

Article Type: Research Article

Abstract: Porous calcium polyphosphate (CPP) constructs of desired density were formed by sintering CPP powders. Articular cartilage was formed on these constructs in cell culture over an 8-week period with the resulting cartilage layer forming on the CPP surface and within the near surface pores thereby mechanically anchoring the cartilage to the CPP. The biphasic constructs so formed were implanted in sheep femoral condyle sites and left for short-term periods (3 to 4 months) or longer periods (9 months). Implant fixation within the condyle sites was achieved through bone ingrowth into the inferior CPP pores. The properties and characteristics of the …as-in vitro-formed, short- and long-term implanted tissues were compared. The results indicated that such implants might be useful for repair of small subchondral defects. Show more

Keywords: Articular cartilage repair, osteochondral implants, porous calcium polyphosphate, tissue engineering, implants, in vitro and in vivo studies, tissue ingrowth

DOI: 10.3233/THC-2007-15105

Citation: Technology and Health Care, vol. 15, no. 1, pp. 47-56, 2007

Authors: Dickson, Glenn | Buchanan, Fraser | Marsh, David | Harkin-Jones, Eileen | Little, Uel | McCaigue, Mervyn

Article Type: Research Article

Abstract: Orthopaedic tissue engineering combines the application of scaffold materials, cells and the release of growth factors. It has been described as the science of persuading the body to reconstitute or repair tissues that have failed to regenerate or heal spontaneously. In the case of bone regeneration 3-D scaffolds are used as a framework to guide tissue regeneration. Mesenchymal cells obtained from the patient via biopsy are grown on biomaterials in vitro and then implanted at a desired site in the patient's body. Medical implants that encourage natural tissue regeneration are generally considered more desirable than metallic implants that may need …to be removed by subsequent intervention. Numerous polymeric materials, from natural and artificial sources, are under investigation as substitutes for skeletal elements such as cartilage and bone. For bone regeneration, cells (obtained mainly from bone marrow aspirate or as primary cell outgrowths from bone biopsies) can be combined with biodegradable polymeric materials and/or ceramics and absorbed growth factors so that osteoinduction is facilitated together with osteoconduction; through the creation of bioactive rather than bioinert scaffold constructs. Relatively rapid biodegradation enables advantageous filling with natural tissue while loss of polymer strength before mass is disadvantageous. Innovative solutions are required to address this and other issues such as the biocompatibility of material surfaces and the use of appropriate scaffold topography and porosity to influence bone cell gene expression. Show more

Keywords: Bone, biodegradable polymers, biomaterials, cell therapy, fracture repair, orthopaedics, tissue engineering

DOI: 10.3233/THC-2007-15106

Citation: Technology and Health Care, vol. 15, no. 1, pp. 57-67, 2007