Figure 4. A: Confocal images of fibrin networks for different fibrinogen concentrations (left to right): 0.5 mg/mL, 2 mg/mL, 3 mg/mL, and 4 mg/mL.

Scale bar is 30 . B,C: Diffusivity of different probes in fibrin gel as a function of (B) and fibrinogen concentration (C): circles - thrombin molecules, squares - Fab IgG fragments, diamonds - azobenzene-labeled BSA molecules [19], left triangles - 228 nm diameter PEG-coated particles [20], right triangles - 526 nm diameter PEG-coated particles [20], 1 - Johnson's model [38] Equation (3) (Text S2); 2 and 3 - thrombin and IgG fits obtained using Equation (2). All data points refer to fibrin gels formed at 7.5 pH and thrombin concentration of 1 NIH U/mL.