Figure 1
Dynamic morphology of thrombin-stimulated platelets. (a) SICM topography image sequence of the spreading process of an unstimulated human platelet (contact with the surface at t = 00:00). After the spreading process (at about 20 minutes), the morphology did not change remarkably. (b) Image sequence of the spreading process of a human platelet stimulated with 0.5 U/mL thrombin prior to contact with the surface. The platelet morphology showed dynamic changes after the spreading process was completed. (c) Image sequence of an unstimulated spread platelet with the addition of 0.5 U/mL thrombin at t = 00:00. The platelet morphology became dynamic after the addition of thrombin. Before the addition of thrombin, the platelet has been allowed to adhere and spread for 30 minutes to complete the spreading process. (d) Overview image and high-speed image sequences of the platelet periphery (top row) and of the platelet body (bottom row) of a spread thrombin-stimulated platelet. The high-speed image sequences were recorded 1 and 9 min, respectively, after the overview image. Two modes of dynamics were observed: lamellipodium waves at the platelet periphery (top row, arrows, red traces in the last image show the path of motion) and dynamic protrusions on the platelet body (bottom row, arrows, blue traces in the last image show the path of motion). The dashed lines show the initial platelet edge (top row) or the initial protrusions (bottom row). To increase the contrast of the protrusions, the large-scale curvature of the platelet body was removed (bottom row, s. “Methods”). The full image sequences are provided as Supplementary Movies S1–3. Scale bars: 2 µm (a–c), 1 µm (d).
