Parameterizing cell movement when the instantaneous cell migration velocity is ill-defined

• Published in: Physica A 2020-07, Vol.550, p.124493, Article 124493
• Main Authors: Thomas, Gilberto L., Fortuna, Ismael, Perrone, Gabriel C., Glazier, James A., Belmonte, Julio M., de Almeida, Rita M.C.
• Format: Article
• Language: English
• Subjects: Cell migration; Fürth equation
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2020.124493

Cell crawling has usually been characterized by a diffusion constant D and instantaneous velocity 〈|v→|2〉. However, experimentally 〈|v→|2〉 diverges. A three regime (diffusive-ballistic-diffusive) modified Fürth equation parameterized by D, the dimensionless excess diffusion coefficient S and the persistence time P is compatible with experiment. S allows comparison of trajectories across experiments and sets limits on the intervals and duration of experiments required to assess cell movement. Cell trajectories in a variety of published experiments are consistent with longitudinal Langevin dynamics and a transverse Wiener process with S∼1+constant∗D−1. •Experimental data show quasi-diffusive behavior for very small-time intervals.•Diffusive behavior cannot be attributed to image acquisition segmentation errors.•Instantaneous velocity is not well-defined when small-time scale regime is present.•Velocity autocorrelation function differs from Langevin behavior at small-time scale.•Small-time scale depends on the cell type and/or experimental setup.