Cell-by-cell analysis of the relationship between cell area and GFP intensity or actin cytoskeleton in NIH3T3 cells. Panels A-C represent cells transfected with the GFP-TN-C promoter construct grown on (A) thin films of fibrillar collagen; (B) thin films prepared from a lower concentration of collagen; (C) thin films of fibronectin. Panels D-F represent FITC-phalloidin intensity in NIH3T3 cells on (D) thin films of fibrillar collagen; (E) thin films prepared from the lower concentration collagen; (F) thin films of fibronectin. Cells in 50 fields were imaged for each treatment. Lines are the result of least squares analysis. r = Spearman rank order correlation coefficient.