The Effect of Acoustic Exposure Parameters on Cell Membrane Permeabilisation by Ultrasound and Microbubbles.

This work investigates the mechanism of sonoporation through the effect of ultrasound exposure parameters with microbubbles in a suspension of KHT-C cells. We investigated the effect of acoustic pressure, pulse repetition frequency, pulse duration, insonation time and frequency. Flow cytometry and fluorescence microscopy were used to quantify permeability and viability of treated cells. Scanning electron microscopy images showed pores of up to 500nm after treatment, indicating that the mechanism of permeabilisation was the formation of pores on the surface of cell membranes. Cell permeability increases and viability decreases with peak negative pressure, duty cycle and insonation time. Higher pulse centre frequencies are more effective at permeabilising cells, but also at killing them. In this study, the highest Therapeutic Ratio is achieved at 570kPa peak negative pressure, 8μs pulse duration, 3kHz pulse repetition frequency, 500kHz centre frequency and 12 seconds of insonation time; Definity at 3.5% volume concentration. This implies that ultrasound can be optimized with respect to the therapeutic application. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]