The role of inertial cavitation of ultrasound constrast agents in producing sonoporation

Monica M. Forbes, William D. O'Brien

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The objective of this project is to elucidate the relationship between ultrasound contrast agents (UCA) and sonoporation by varying the peak rarefactional pressure (Pr) in a threshold type study. The results of sonoporation in the presence of Optison™ or Definity® are directly compared to the collapse thresholds of the respective contrast agent to uncover the role inertial cavitation plays in sonoporation. Chinese Hamster Ovarian (CHO) cells were grown as a monolayer in a 96-microwell plate. Each well was filled with an exposure medium consisting of 0.05 mL Fluorescein isothiocyanate-dextran (FITC-dextran), 8.8 μL Optison™ or 0.57 μL Definity®, and Phosphate Buffered Saline. CHO cells were exposed for 30 s to pulsed ultrasound at 3 MHz center frequency, 5-cycle pulse duration, and 10-Hz pulse repetition frequency. Pr was varied over a range from 10 kPa to 3.5 MPa. Flow cytometery was used to determine the percentage of positively labeled cells. Over the Pr range applied, the sonoporated cells in the presence of Optison™ increased from 0.63% to 10.21%, with a maximum occurring at 2.4 MPa. Above 2.4 MPa, a significant drop in sonoporation activity was observed. Sonoporation in the presence of Definity® presented the same trend, with sonoporated cells increasing from 5.26% to 26.39%, with a maximum occurring 172 kPa. Above 172 kPa, a drop in sonoporation activity was observed. These results illustrate that sonoporation is not due inertial cavitation of the UCA. Instead the evidence directly suggests that the sonoporation effect was caused by linear and/or nonlinear oscillation of the UCA as these responses occur at lower Pr where sonoporation activity was present. Moreover, at higher pressures, the UCAs are rapidly collapsing and as such, are likely not present for enough time to significantly oscillate, thus minimal sonoporation activity was observed.

Original languageEnglish (US)
Title of host publication2007 IEEE Ultrasonics Symposium Proceedings, IUS
Number of pages4
StatePublished - Dec 1 2007
Event2007 IEEE Ultrasonics Symposium, IUS - New York, NY, United States
Duration: Oct 28 2007Oct 31 2007

Publication series

NameProceedings - IEEE Ultrasonics Symposium
ISSN (Print)1051-0117


Other2007 IEEE Ultrasonics Symposium, IUS
Country/TerritoryUnited States
CityNew York, NY


  • Inertial cavitaion
  • Sonoporation
  • Thresholds
  • Ultrasound contrst agent

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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