Direct imaging of FXa and platelets. (A) Digital composite fluorescence and brightfield images of representative thrombi in HB mice infused with unlabeled FV-810^SYA (600 µg/kg) and labeled Alexa₆₄₇-FXa_i (80 µg/kg) at 10, 40, 70, 100, 130, and 190 seconds after injury; FXa_i (cyan), platelets (red), and overlap between FXa_i and platelets (white). (B-C) Kinetics of Alexa₆₄₇-FXa_i (n = 5 mice; 22 thrombi) and platelets (n = 5 mice; 22 thrombi) fluorescence accumulation over time. (D) Confocal imaging of Alexa₆₄₇-FXa_i and platelets 4 minutes after laser injury, merged or presented individually; step size = 1 µm in z-plane; total section 30 µm. Images depict different orientations of the same thrombus. (D) Upper panel: horizontal orientation; lower panel: 90 degrees to the right. Bar represents 30 µm. Platelet accumulation was monitored using Alexa₅₅₅-labeled rat anti- CD41 F_(ab)2 antibody.