Durotaxis Modeling and Experimental Validation

Introduction: Cell migration is an essential phenomenon in many physiological processes such as morphogenesis and wound healing. In the absence of external stimuli cell crawling is a quasi-straight path over short time intervals while exhibiting a Brownianlike motion over long time intervals. As a result, this cell motion can be described as a persistent random walk and it is called random motility. The presence of biochemical or biophysical cues can influence cell migration transforming it in a biased random movement. Recent studies have shown that cells, in particular fibroblasts, are able to recognize the mechanical properties of a substratum over which they move and that these properties direct the motion through a phenomenon called durotaxis [1]. The mechanism through which it occurs can be explained as follows: a cell probes its local environment using protrusions of its cytoskeleton to attach itself to the substratum at different points; the protrusions that land on softer regions are irregular and highly dynamic, while protrusions that are anchored on stiffer regions are regularly shaped and stable [2]. As a result, the cell motion is biased in such a way that stiffer regions are preferable for cell migration. Based on this mechanism we propose a mathematical model for the description of this phenomenon. The model is also validated through experimental measurements on poly(ethylene glycol) (PEG) based substrata.