Volume 111, Issue 7, Pages 1487-1495 (October 2016) Direct Tracking of Particles and Quantification of Margination in Blood Flow  Erik J. Carboni, Brice H. Bognet, Grant M. Bouchillon, Andrea L. Kadilak, Leslie M. Shor, Michael D. Ward, Anson W.K. Ma  Biophysical Journal  Volume 111, Issue 7, Pages 1487-1495 (October 2016) DOI: 10.1016/j.bpj.2016.08.026 Copyright © 2016 Biophysical Society Terms and Conditions

Figure 1 (a) Blood flow showing the formation of CFL within a microchannel. (b) Plane of focus for particle tracking with labeled imaging positions. (c) Schematic diagram of the microfluidic channel used in this study with the plane of focus for particle tracking. To see this figure in color, go online. Biophysical Journal 2016 111, 1487-1495DOI: (10.1016/j.bpj.2016.08.026) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 2 (a and b) Particle count per segment as a function of the normalized y-position for 2.11-μm particles suspended in (a) water and (b) blood. Volumetric flow rate: 0.24 μL/min; apparent wall shear rate: 61 s−1. (c and d) Velocity profiles of 2.11-μm particles suspended in (c) water and (d) blood. (e and f) Total weighted particle count per segment (Pithsegment) as a function of the normalized y-position for (e) water and (f) blood. To see this figure in color, go online. Biophysical Journal 2016 111, 1487-1495DOI: (10.1016/j.bpj.2016.08.026) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 3 (a–c) Margination parameter (M) for different sizes of particles: (a) suspended in water at the inlet (x = 0) and outlet (x = 10 mm), (b) suspended in water or blood at x = 0, and (c) suspended in blood at different channel positions (x). For (a–c), apparent wall shear rate = 61 s−1. (d) Margination parameter (M) of 0.53-μm particles suspended in blood at varying flow rates at the outlet (x = 10 mm). To see this figure in color, go online. Biophysical Journal 2016 111, 1487-1495DOI: (10.1016/j.bpj.2016.08.026) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 4 (a–f) Representative plots of average y-velocities for individual particles in water or blood: (a and b) 0.53-μm, (c and d) 0.84-μm, and (e and f) 2.11-μm particles. To see this figure in color, go online. Biophysical Journal 2016 111, 1487-1495DOI: (10.1016/j.bpj.2016.08.026) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 5 (a and b) Mean-square displacement as a function of time for 2.11-μm particles in (a) water and (b) blood. Theoretical lines (yellow) on both plots have a slope equal to two times the Brownian diffusivity, which is calculated to be ∼0.6 μm2/s using the Stokes-Einstein-Sutherland equation. From data fitting, the effective diffusivities were estimated to be ∼1.9 μm2/s and ∼15.4 μm2/s for water and blood, respectively. To see this figure in color, go online. Biophysical Journal 2016 111, 1487-1495DOI: (10.1016/j.bpj.2016.08.026) Copyright © 2016 Biophysical Society Terms and Conditions