Toward guided tissue and bone regeneration: morphology, attachment, proliferation, and migration of cells cultured on collagen barrier membranes. A systematic review.
ABSTRACT Collagen barrier membranes are frequently used in both guided tissue regeneration (GTR) and guided bone regeneration (GBR). Collagen used for these devices is available from different species and is often processed to alter the properties of the final product. This is necessary because unprocessed collagen is rapidly resorbed in vivo and demands for barrier membranes are different in GTR and GBR. This systematic literature review attempts to evaluate possible effects of collagen origin and mode of cross-linking on the potential of different cells to attach to, proliferate on, and migrate over barrier membranes in vitro. Seventeen original studies, selected by a systematic process, are included in this review. The results show that fibroblasts of different species and originating tissues as well as bone-forming cells are able to attach to collagen membranes irrespective of collagen origin or mode of processing. Different cell types behave differently on identical membranes. Many pieces of evidence are currently available, and we attempted to elucidate the effects of collagen origin and mode of processing on cellular behavior, but further research will be required before it will be possible to predict for certain the effect a specific procedure will have with a given product.
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ABSTRACT: Cell migration on and through extracellular matrix is fundamental in a wide variety of physiological and pathological phenomena, and is exploited in scaffold-based tissue engineering. Migration is regulated by a number of extracellular matrix- or cell-derived biophysical parameters, such as matrix fiber orientation, pore size, and elasticity, or cell deformation, proteolysis, and adhesion. We here present an extended Cellular Potts Model (CPM) able to qualitatively and quantitatively describe cell migration efficiencies and phenotypes both on two-dimensional substrates and within three-dimensional matrices, close to experimental evidence. As distinct features of our approach, cells are modeled as compartmentalized discrete objects, differentiated into nucleus and cytosolic region, while the extracellular matrix is composed of a fibrous mesh and a homogeneous fluid. Our model provides a strong correlation of the directionality of migration with the topological extracellular matrix distribution and a biphasic dependence of migration on the matrix structure, density, adhesion, and stiffness, and, moreover, simulates that cell locomotion in highly constrained fibrillar obstacles requires the deformation of the cell's nucleus and/or the activity of cell-derived proteolysis. In conclusion, we here propose a mathematical modeling approach that serves to characterize cell migration as a biological phenomenon in healthy and diseased tissues and in engineering applications.Mathematical Biosciences and Engineering 02/2013; 10(1):235-61. DOI:10.3934/mbe.2013.10.235
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ABSTRACT: Calcium deficient hydroxyapatite (CDHA) having an average particle size of 45 nm was synthesized by reverse emulsion method. It was converted to the respective biphasic calcium phosphate (BCP, 226 nm) and β-tricalcium phosphate (TCP, 450 nm) by calcination at 800 °C and 1000 °C, and the BCP consisted of 92% TCP and 8% CDHA. Subsequently, chitosan was mixed with calcium phosphates to prepare CDHA/chitosan, BCP/chitosan, and TCP/chitosan membranes. The initial moduli of the BCP/chitosan and TCP/chitosan membranes were about 1.9 times that of the pure chitosan membrane; and the elongations at break were almost 6 times. The CDHA/chitosan and BCP/chitosan could induce mineralization of apatite on the membranes by increasing 20.6 and 16.3 wt.%, respectively, after 24 days in the simulated body fluid. Moreover, the BCP/chitosan exhibited superior osteoblast cell attachment and proliferation than the other membranes. It has the potential to be used as the barrier membrane for guided bone regeneration.Carbohydrate Polymers 04/2012; 88(3):904–911. DOI:10.1016/j.carbpol.2012.01.042 · 3.92 Impact Factor
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ABSTRACT: Gingival cells of the oral connective tissue are exposed to complex mechanical forces during mastication, speech, tooth movement and orthodontic treatments. Especially during wound healing following surgical procedures, internal and external forces may occur, creating pressure upon the newly formed tissue. This clinical situation has to be considered when developing biomaterials to augment soft tissue in the oral cavity. In order to pre-evaluate a collagen sponge intended to serve as a substitute for autogenous connective tissue grafts (CTGs), a dynamic bioreactor system was developed. Pressure and shear forces can be applied in this bioreactor in addition to a constant medium perfusion to cell-material constructs. Three-dimen-sional volume changes and stiffness of the matrices were ana-lyzed. In addition, cell responses such as cell vitality and extracellular matrix (ECM) production were investigated. The number of metabolic active cells constantly increased under fully dynamic culture conditions. The sponges remained elastic even after mechanical forces were applied for 14 days. Analysis of collagen type I and fibronectin revealed a statistically significant accumulation of these ECM molecules (P < 0.05–0.001) when compared to static cultures. An increased expression of tenascin-c, indicating tissue remodeling processes, was observed under dynamic conditions only. The results indicate that the tested in vitro cell culture system was able to mimic both the biological and mechanical environments of the clinical situation in a healing wound. Biotechnol. Bioeng. 2010;xxx: xxx–xxx.