1. FIGURE 25.1 Effect of Cell Density on Expression of GFAP in C6 Cells. Flask cultures were grown to different densities, fixed, and stained by immunoperoxidase for GFAP (see Plate 11b), and the percentage of stained cells was calculated from replicate counts in representative fields. (Courtesy of R. L. Shaw).

2. FIGURE 25.2 Histotypic and Organotypic Culture.

3. FIGURE 25.3 Organ Culture. Small fragment of tissue on a filter laid on top of a stainless steel grid over the central well of an organ culture dish.

4. FIGURE 25.4 Dividing Cells in Spheroids. Sections through mature spheroids of approximately 600- to 800-μm diameter. (a) Autoradiograph labeled with [ 3 H]thymidine, showing restriction of label to periphery. (b) Immunoperoxidase staining with anti- BUdR, showing similar restriction of label to periphery. (Courtesy of Ali Neshasterez; see also Plate 18a).

5. FIGURE 25.5 Rotating Chamber System. Miniperm. The concentrated cell suspension in the left chamber is separated from the medium chamber by a semipermeable membrane. High-molecular- weight products remain with cells and can be harvested from the sampling ports, while replenishment of the medium is carried out via the right-hand port. Mixing is achieved by rotating the chamber on a roller rack. (Greiner Bio-one; Sigma.)

6. FIGURE 25.6 Synthecon Rotatory Cell Culture System. In the rotary cell culture system (RCCS), cells are maintained in suspension by adjusting the rotation speed of a cylindrical culture chamber. A gaspermeable silicone membrane core gives the cells ample gas while disallowing shear causing bubbles. (a) Reusable cylindrical chamber on RCCS. (b) Disposable chambers. (See also Plate 22c.) TheNASAdesigned bioreactor is available from Synthecon, Inc., Houston, Texas, and distributors worldwide. (Courtesy of Synthecon, Inc.)

7. FIGURE 25.7 Filter Well Inserts. Sectional diagram of a hypothetical filter well insert. (a) Monolayer grown on top of the filter. (b) Monolayer grown on matrix on top of a filter. (c) Interactive cell layer added to the underside of a filter. (d) Interactive cell layer added to thematrix. (e) Interactive cell layer added to the underside of the filter with matrix coating above. (See also Plates 19–21.)

8. FIGURE 25.8 Transwells. Filter well inserts in a 12-well plate, with a filter well insert alongside. (Transwells: Corning.)

9. FIGURE 25.9 Scaffolds and Matrices. Overview of types of scaffolds and matrices used in tissue engineering constructs. Many different geometries have been employed including linear fibers or tubes (top), two-dimensional mesh screens or filters (center), and three-dimensional cubes or spheres (bottom). Although nondegradable materials have been used (left-hand labels in each column) the trend is toward biodegradable scaffolds (right-hand labels in each column) such as collagen, gelatin, polyglycolic acid (PGA) or polylactic acid (PLA), and calcium phosphate.

10. FIGURE 25.10 MRI of Cartilage Construct. Brightness of image is proportional to cell density. Distances on grid are in mm. (Courtesy of Dr. Kevin Brindle; from Thelwall et al., 2001.)