Figure 3.

Diffusion coefficients of FN ligands at the cell-substrate interface measured by in situ analysis of FN fibrillogenesis. (a) Adherent HUVEC at 30 min after seeding visualized by reflection interference contrast microscopy and the corresponding fluorescence image of preadsorbed TAMRA-labeled FN. The area of snapshots in (b) and Movie S1 is indicated. Scale bar: 30 μm. (b) Snapshots of Movie S1of preadsorbed TAMRA-labeled FN after 0 min, 5 min, and 10 min. The arrow indicates a growing FN fibril. Scale bar: 5 μm. (c) Intensity of a growing FN fibril versus time on a PEMA surface. From the measured fibril intensity I(t) the background fluctuation I_∞(t) has been subtracted and normalized to the mean background level $\langle I_{\infty }\rangle$. A fit of the intensity by using Eq. 5 in the Supporting Material yields a diffusion coefficient of D = 3.0 × 10⁻¹² cm²/s. (d) Mean diffusion coefficients of FN on the different polymer surfaces. Error bars indicate mean + SD.