Acoustic Characteristics of Microbubbles: Effect of Acoustic Pressure and Pulse Duration

The acoustic mechanism of ultrasound- Microbubble (MB) mediated sonoporation enhanced permeability of cell membranes has been associated with inertial and stable cavitations. The main objective of this study was to characterise acoustic behaviour of MB, under varying acoustic pressure and pulse duration using passive cavitation detection(PCD) technique. MBs were exposed to 1 MHz ultrasound pulse at varying acoustic pressure (0-1.5 MPa), pulse duration (5-30μs) at pulse repetition frequency of 1 KHz for insonation time of 1 second. The cavitation phenomena of MBs were detected passively using two transducers at center frequencies of 0.5 and 2.25 MHz. The MB acoustic response was characterised using FFT algorithm and cavitation dose method. Results indicated that the nonlinear oscillation of MBs increased with PNP and pulse duration. The integrated cavitation dose (ICD) increased with acoustic pressure and decreased with pulse duration. Definity MB showed greater ICD than Artenga MB.