Figure 2.

Cell shape and contractile force response to electroporation. (a, b) Cell responses to electroporation at 500 V, 1000 V, and 1500 V in the (a) parallel orientation (441 V cm⁻¹, 882 V cm⁻¹, and 1323 V cm⁻¹ respectively) and (b) perpendicular orientation (455 V cm⁻¹, 911 V cm⁻¹, and 1366 V cm⁻¹ respectively). The onset of membrane disruption by electroporation is visualized for 1000 V∥ by the inclusion of YO-PRO-1 (green, background subtraction and thresholding used to remove background signal, see the Methods). Cells show rounding, membrane blebbing, and an eventual return to a characteristic elongated state in a voltage- and orientation-dependent manner. Scale bars are 25 μm. (c, d) Average fiber deflection, cell length, and contractile force post-EP for cells in the parallel (c) and perpendicular orientation (d). Cells in the parallel orientation show rapidly decreased length and contractility and recovery within 1–2 h. For the perpendicular orientation, no response occurs at 500 V, a moderate response occurs at 1000 V, and an extreme response is seen at 1500 V. Unexpectedly, fiber deflection and force plots show a transitory increase shortly after electroporation (see arrows on plots), indicating multiple stages in the recovery process. Error bands show standard error. (e, f) Maximum percent decrease in force and cell length is greatest at high voltages. (g) Electroporation at high electric fields causes significant cell death, particularly in the perpendicular orientation.