NNRLFs were cultured in Gelfoam sponges for 14 days, fixed, sectioned and incubated without (A and C) and with primary antibodies to elastin (B), and type I collagen (D), followed by incubation with FITC-linked (A and B, green) or Cy3-linked (C and D, red) secondary antibodies. Secondary antibody alone control samples were visualized using a 20x objective in order to be able to observe the low background fluorescence. The primary antibody samples were observed with a 10x objective so that the distribution of elastin and collagen deposition could be visualized throughout a larger region of the cell-Gelfoam constructs.