Contact Guidance 1 Contact or topographical guidance refers

  • Slides: 10
Download presentation
Contact Guidance 1. Contact or topographical guidance refers to the tendency of a cell

Contact Guidance 1. Contact or topographical guidance refers to the tendency of a cell to be oriented and ultimately guided in its direction of migration by substratum topography. 2. For example, cells cultured on a grooved surface become oriented with the grooves and then migrate in the direction of the grooves, not across them.

To measure the strength of cell attachment to surfaces by detaching cells attached to

To measure the strength of cell attachment to surfaces by detaching cells attached to some substrata 1. Micromanipulation 2. Flow cells 3. Jet impingement 4. Centrifugation

Rugophobia 1. The term Rich and Harris to describe the tendency of fibroblasts to

Rugophobia 1. The term Rich and Harris to describe the tendency of fibroblasts to shun rough surfaces. 2. In the experiments of Rich and Harris the rough surface was produced by simply rubbing a glass rod against a tissue-culture dish. Rich and Harris, J. Cell Sci. 1981

Rugophilia 1. Opposite response of rugophobia 2. Macrophage preferred rough surfaces to smooth ones

Rugophilia 1. Opposite response of rugophobia 2. Macrophage preferred rough surfaces to smooth ones and were said to exhibit rugophilia. 3. In general, it appears that osteoblasts attach and function more effectively on rough as opposed to smooth surfaces. Rich and Harris, J. Cell Sci. 1981

Tissue Response to Surface Roughness Includes…. . 1. Rough surfaces alter cell-shape and would

Tissue Response to Surface Roughness Includes…. . 1. Rough surfaces alter cell-shape and would be expected to alter gene expression 2. The response of cells to various agents is modified by the surface texture on which they are cultured. 3. Cell selection : the population of cells attached to the implant would be expected to be determined at least to some extent by the roughness.

Problems in interpreting the literature (In vitro studies) 1. The terms osteoblast and osteoblast-like

Problems in interpreting the literature (In vitro studies) 1. The terms osteoblast and osteoblast-like have been used rather freely in describing a wide range of cell lines whose relationship to the cells that actually form bone in vivo is unclear. 2. Comparisons between tumor cells and normal cells often find multiple differences, and users of such cell lines must hope that these differences does not interfere with the phenomenon being studied.

Problems in interpreting the literature (In vitro studies) 3. Primary cell cultures such as

Problems in interpreting the literature (In vitro studies) 3. Primary cell cultures such as those obtained by dissociating new-born rat calvariae or bone marrow are clearly heterogenous and probably sensitive to the particular conditions of isolation, and thus their use brings other problems in interpretation.

Haptotaxis 3. If the material, such as titanium, is more strongly adhesive to cells

Haptotaxis 3. If the material, such as titanium, is more strongly adhesive to cells than are other cells or extracellular matrix, then one would expect the cells of the tissue to migrate onto the implant. 4. Conversly, if the implant is poorly adhesive, as might occur if there were extensive hydrocarbon contamination on a titanium surface, the cells would prefer to attach to each other and extracellular matrix (capsule formation)

Haptotaxis 1. The term introduced by Carter to describe the directional cell movement that

Haptotaxis 1. The term introduced by Carter to describe the directional cell movement that occurs as a result of adhesive gradients on the substratum. 2. When an implant is inserted into a tissue it would be expected to create an adhesive gradient. Carter S. B. Nature 1967

Concept of Tensegrity 1. Proposed by Ingber. 2. Tensegrity structures found in biology constitute

Concept of Tensegrity 1. Proposed by Ingber. 2. Tensegrity structures found in biology constitute a particular form of arcitecture in which tension is continuously transmitted across all structural members so that an increase in tension in one member results in increased tension throughout the entire structure. Ingber et al. Int. Rev. Cytology. 1994