Extended Data Fig. 1: The method used to quantify collective cell movement does not appreciably affect our measurements of scale and conformal invariance.
From: Evidence of universal conformal invariance in living biological matter
We measured the cell movement using both Particle Image Velocimetry (PIV, open symbols) and direct cell tracking (or Particle Tracking Velocimetry, PTV, filled symbols) and used each to calculate a respective set of zero-vorticity isocontours (see Materials and Methods for further details). (a) The complete perimeter and accessible external perimeter as a function of their radius of gyration using the isocontours obtained from the two different methods (analogous to that shown in Fig. 2a). Open symbols show PIV data, closed symbols show PTV data. (b) The left-passage probability as a function of the polar coordinate calculated using data from the two different methods, plotted alongside the analytic curve for κ = 6 (dashed black line). Top panels shows results for monolayers of MDCK cells and bottom panels shows results for wild-type P. aeruginosa cells. Error bars indicate the s.d. about the mean for the n > 85 flow field measurements that were obtained for each dataset.
