Cavitation bubble-driven cell and particle behavior in an ultrasound standing wave.
The behavior of human erythrocytes and 1-microm-diameter fluorescent latex beads in the presence of Optison contrast agent in a single half-wavelength (lambda/2) ultrasound standing wave (USSW) resonator has been studied. The particle movements were observed with an epi-fluorescent microscope and the velocity of the particles and cells was measured by particle image velocimetry (PIV). Acoustic emissions were monitored with a microphone and a spectrum analyzer. Optison contrast agent disintegrated immediately on exposure to ultrasound of 0.98-MPa acoustic pressure amplitude or higher in a chamber driven at its resonance frequency of 1.56 MHz. A discrete cloud of active microbubbles, detected at the pressure node plane, disappeared gradually and was completely lost within 15 s. The microscopy showed three-dimensional regions of circulation of both 1-microm tracer particles and erythrocytes in planes perpendicular to the pressure node plane. A numerical simulation showed that, for parameters that conform to the experimental conditions, a bubble of a subresonance size moves towards and translates about a pressure node plane. This result is in agreement with the experimental observation that the particle and cell circulation is induced by the presence and/or translational motion of microbubbles at the pressure node plane.
Kuznetsova
Larisa A
LA
School of Biosciences, Cardiff University, Cardiff CF10 3TL, United Kingdom. kuznetsoval@cardiff.ac.uk
Khanna
Sanjay
S
Amso
Nazar N
NN
Coakley
W Terence
WT
Doinikov
Alexander A
AA
D000162:Acoustics / Q000295:instrumentation*; D004912:Erythrocytes / Q000502:physiology; D006801:Humans; D008962:Models, Theoretical; D011312:Pressure; D014159:Transducers; D014465:Ultrasonics; D014741:Video Recording