Figure 4

Determination of gap junction (GJ) permeability from cell–cell propidium iodide (PI) transfer and subsequent intracellular diffusion using an 1D semi-infinite medium diffusion model. (A) Sonoporation (t = 0) of a single cell (white dashed outline) via a membrane-bound microbubble (yellow arrow) permitted intracellular uptake of PI and PI transport into a neighboring cell (yellow dashed outline). Data from the blue highlighted frames represent steady state of PI in the sonoporated cell and were used for model fitting. Blue dashed line within the recipient cell indicates the 1D spatial distance from the GJ separating the sonoporated cell and recipient cell. (B) Plots of normalized PI concentration from model prediction and experimental data along the blue dash line within the recipient cell in (A) at different time points. Data points representing PI intensity within the nucleus of the recipient cell were not shown and not used in model fitting. Ultrasound pulse duration was 8 µs, acoustic pressure 0.4 MPa.