Special Mechanical and Civil Engineering Seminar

Ultrasonic technologies pervade the field of medicine. At low intensities (<0.1 MPa acoustic pressures) ultrasound has been exploited for diagnostic purposes; whereas at much higher pressures (>10 MPa), focused US can be exploited to thermally ablate tumors in a minimally invasive fashion. It is, however, with intermediate pressures that a compelling range of bio-effects can be achieved, ranging from controllable membrane disruption (for the purposes of molecular delivery), to the induction of apoptosis (programmed cell death). Moreover, these effects may be enhanced significantly when microscopic bubbles are present during ultrasound exposure.  At Dundee, we have developed a programme of research that is focused towards understanding the dominant processes of cause and effect at a fundamental level, and with refined spatial and temporal resolutions. Here, a hybrid approach coupling optical trapping with ultra-high speed imaging has been exploited to ascertain the ultrasound-stimulated behaviour of micro-bubbles as a function of their proximity to nearby cells and tissues [1], as well as the resultant physical effects.

Furthermore, in collaboration with two Japanese groups, we have also sought to identify the fundamental biological processes that arise as a consequence, not only of such cavitation-driven effects, but also that of ultrasound alone [2].

The first half of the presentation will describe the development and operation of the unique hardware at Dundee, as well as surveying our most recent observations on multi-microbubble dynamics. Following this, a full description of the fundamental biological effects and their pathway dependencies will be covered, together with our strategy for future translational exploitation.

[1] Membrane disruption by optically controlled microbubble cavitation

PA Prentice, A Cuschieri, K Dholakia, MR Prausnitz & PA Campbell

Nature-Physics 1 (2) 107 (2005)

[2] DNA double strand breaks induced by cavitational mechanical effects of ultrasound in cancer cells

Y Furusawa, Y Fujiwara, PA Campbell, QL Zhao, R Ogawa, MA Hassan, Y Tabuchi, I Takasaki, A Takahashi & Kondo PloS One   7 (1) e29012 (2012)