Search Swinburne Research Bank
Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/189925
- The effect of a surface on the response of microbubbles to ultrasound
- Payne, Edward; Manasseh, Richard; Ooi, Andrew
- Experimental data on the response frequencies of microbubbles are compared with a range of theoretical and numerical models. The objective was to determine how the surface affected the bubble resonant frequency. Recent proposals for ultrasound molecular imaging (targeted diagnostics) and targeted therapeutics require contrast agent microbubbles to be bound to a target surface, usually vascular endothelium expressing pathological markers to which the bubble shell has been made specific. Continuous-wave ultrasound was applied to microbubbles attached to surfaces both as individuals and in pairs. An optical imaging system acquired data on the bubble radius as a function of the transmitted signal phase. By varying the bubble size, the peak response frequency could be determined. When multiple bubbles are present, there are multiple modes of coupled oscillation, even when the behaviour is linear. An ultra-high speed camera acquired data on both the symmetric and antisymmetric modes. All theories predict a downwards shift in the resonant frequency owing to the presence of the surface, although the size of the shift depended on the theoretical assumptions applied. Nonlinear calculations were performed numerically for comparison with higher-amplitude cases. An appropriate theory, taking into account the bubble contact angle with the surface, was found to give very good agreement with the data. In conclusion, the resonant frequency of microbubbles is altered by a surface by a factor that can be predicted. Implications for effective imaging of targeted ultrasound contrast agents and for ultrasonic drug delivery are discussed.
- Publication type
- Conference paper
- Ultrasound in Medicine and Biology: abstracts of the 12th World Congress of the World Federation for Ultrasound in Medicine and Biology (WFUMB 2009), Sydney, New South Wales, Australia, 30 August - 03 September 2009, Vol. 35, no. 8, suppl. 1 (Aug 2009), pp. S49-S50, paper no. 0362
- Publication year
- FOR Code(s)
- 1103 Clinical Sciences
- Microbubbles; Surface; Ultrasounds
- Publisher URL
- Copyright © 2009.