Attachment, extracellular matrix proteins

Fibronectin is an extracellular matrix protein that mediates a variety of cellular effects. It is important in cell-cell and cell-substratum interactions ( 3.9), mediates reticuloendothelial cell activity and binds both to Clq (the first component of complement) and to bacteria. It also increases the tu-mouricidal activity of macrophages and activates complement receptors, by regulating the binding of C3b-coated particles to neutrophils. It may mediate attachment of Staphylococcus aureus to neutrophils and may also play a role as an adhesion factor, promoting the adhesion of neutrophils to surfaces. Fibronectin mRNA (8.7-8.8 kb) is detected only at low levels in... 

Several families of integral proteins in the plasma membrane provide specific points of attachment between cells, or between a cell and extracellular matrix proteins. Integrins are heterodimeric proteins (two unlike subunits, a and /3) anchored to the plasma membrane by a single hydrophobic transmembrane helix in each subunit (Fig. 11-22 see also Fig. 7-30). The large extracellular domains of the a and /3 subunits combine to form a specific binding site for extracellular proteins... 

In a study of 52 diverse materials, we found that 48 chemically dissimilar substrata bind fibronectin and, thereby, permit the attachment and growth of cells. Our results indicate that the ability of a polymer to bind fibronectin and other extracellular matrix proteins is an important determinant of the biological properties of the polymer. Poly(hydroxyethy1-methacrylate) was found to be unique in that it does not bind fibronectin and, thereby, does not support cell adhesion. 

In 2D cell culture on chip, cell adhesion has been extensively studied on patterned surfaces for it is critical to cellular functions. Micropattems have been used to study the cellular interactions with various materials such as metals, polymers, self-assembled monolayers, extracellular matrix proteins, cell adhesion peptides, and other bioactive molecules. The physical and chemical properties of a substrate affect the attachment and growth of cells on it, and many studies have demonstrated that different topographical features of a surface affect cell attachment. Glass, sflicon, and polydimethylsiloxane (PDMS) are widely used as substrate materials of ceU culture microchips. 

Geometrical lab chips with micropattemed surfaces are used to geometrically control the cell attachment to the matrix materials, which provide opportunities to explore the fundamental effect of geometrical-driven ceU morphology changes to stem cell differentiation. Microcontact printing techniques are widely used to pattern the shapes of individual cells on a substrate (Fig. 1). Briefly, the procedure involves the transfer of extracellular matrix proteins from the microfabricated polydimethylsiloxane (PDMS) stamp with micropattems onto the substrate. The nonpattemed... 

Dawson, R.A., Goberdhan, N.J., Freedlander, E., Macneil, S., 1996. Influence of extracellular matrix proteins on human keratinocyte attachment, proliferation and transfer to a dermal wound model. Bums 22, 93—100. 

Chitosan is a well-defined matrix and as a porous scaffold, hepatocytes were found to maintain a rounded morphology when cultured within chitosan scaffolds [27]. Results showed an increase in albumin secretion as well as urea synthesis, vital metaboHc activities of hver cells [27]. Additionally, cross-hnking chitosan gels with glutaraldehyde showed increased urea formation by hepatocytes [28]. Furthermore, chitosan has shown promise as an orthopaedic scaffold. When a sponge form of chitosan was seeded with rat osteoblasts, alkaline phosphatase production was detected, as well as bone spicules, indicating initial bone formation [29]. Also, chitosan scaffolds were found to support chondrocyte attachment and expression of extracellular matrix proteins [30]. 

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