Correlative light and electron microscopy of platelets adherent on an FN-coated grid.

After adherence to the grid for 15 minutes, washed platelets were rinsed and incubated for 1 hour with 1 μM LPA and 20 mg/L FITC-FN. Grids were analyzed by VDIC microscopy, fluorescence microscopy for localization of FITC-FN, and SEM and TEM for immunogold localization of FITC, as described in “Materials and methods.” SEM was done without and with coating of the sample with platinum (pt). Higher magnifications center on the platelet identified by the arrow. Note the linear arrangement of beads on the platelet surface (arrowheads) that correlates with FITC fluorescence (arrowhead). One linear array extends to a neighboring platelet. TEM demonstrates that beads decorate filaments of less than 20 nm in diameter.