Figure 5. The entire dynamic process of pore opening and closing was monitored by transmembrane current in real-time using patch clamp technique and confirmed by the cell-impermeable fluorescent dye influx, diffusion inside the cell and stabilization.

(A) Cell with round microbubble on left and patch clamp tip on right. (B–E) After ultrasound exposure, fluorescence imaging shows influx of propidium iodide (red) from extracellular space, while (F) green viability assay shows cell is alive. (G–H) Transmembrane current changes at the time of ultrasound exposure corroborating delivery. (I) Propidium iodide is proportional to the change in total charge suggesting diffusion-driven transport.

Reproduced with permission from [67].