Figure 4. Asymmetric adhesion across HL-60 population.

(a) Normalized autocorrelations of the dwell time τ(θ) measured as a function of rotation angle θ for many individual cells (N = 30; gray) and their average (red). The average autocorrelation displays peaks at 2nπ (n = 1, 2, 3, 4; red dotted lines and arrows), indicating periodicity in adhesion. (b) Normalized autocorrelations of the dwell time τ(x) measured as a function of position x for the same population of cells (gray) and their average (blue). Without rotation tracking, the autocorrelation fails to display peaks at distances corresponding to multiples of the average circumference π<d>, where <d> is the average cell diameter (blue dotted lines; blue shades indicate the standard deviation due to cell size variations. Both the average and standard deviation are obtained from the average cell diameter, as shown in Fig. 5).