Figure 1

Phase contrast images of NIH3T3 cells on (A) a thin film of fibrillar collagen, (B) a gel of fibrillar collagen, (C) a thin film prepared from a lower concentration of collagen, (D) a thin film of fibronectin. Microscopy images were taken using a 40× objective and the calibration bar equals 10 μm. The small particles observed on the surface are a result of fixative precipitation during the fixing protocol used to preserve the cytoplasmic GFP protein within the cell.