Figure 4. Mechanical testing (stress - strain analysis) of live stem cells using novel microbead tracking method.

Cell surface deformation (strain) is mapped in situ concomitant to delivery of controlled mechanical cues via fluid flow. (A) Two dimensional (2D) images of microsphere displacements on cell surfaces. Calcein green stain marks live stem cells. Red, green, and blue dots indicate respective positions of microbeads at 0, 30, and 60 minutes after flow application. Control shows positions of microbeads in absence of flow. (B) Schematic depiction of flow and non-flow orientation/direction with respect to initial position of microbead (t₀, red). (C) Comparison of microbead displacements on cell surfaces from control cohorts and cohorts exposed to flow. Error bars show standard errors (n = 3), * indicates statistical significance (p<0.05).