Figure 7.

Threshold receptor density of IAV particles binding to receptor gradients as a function of flow rate and virus concentration. (a) Mean threshold receptor density for different virus concentrations and flow rates, from 7 corrals for 1 μL/min and 12 for 5 μL/min. Error bars indicate 95% confidence interval. n.s.: not significant, ***: p < 0.001. (b) Measured and predicted threshold receptor density at different virus concentrations for different flow rates. The theoretical change in threshold receptor density with virus concentration is calculated separately for 1 μL/min and 5 μL/min using eq 6 with as fit parameter. Experimental threshold receptor densities were evaluated over 12 corrals for 5 μL/min and over 22, 7, and 7 corrals for 1 μL/min. Error bars indicate 95% confidence interval. (c) Finite element simulation of laminar flow in a microchannel at a flow rate of 5 μL/min and the resulting drag force on a 112 nm particle. (d) Fitted threshold receptor density at different flow rates using eq 7 with the spring constant k as fit parameter, using 7, 20, and 12 corrals. Error bars indicate standard deviation. (e) Binding profiles and fits at flow rates of 1 μL/min (I), 3 μL/min (II), and 5 μL/min (III). For these profiles, point clouds from 7 (I), 20 (II), and 12 (III) corrals were combined.