Microbubble size isolation by differential centrifugation

Real-time, transcranial monitoring of safe blood-brain barrier opening in non-human primates

“…Once the animal, the targeting coordinates, and the FUS system were set, negative control sonications were performed in the absence of microbubbles (see Figure 2 and below for details). After IV injection of monodispersed 4-5-mm microbubbles that were manufactured inhouse and size-isolated using differential centrifugation [18], the animals were sonicated for a total duration of 2 minutes with an estimated focal maximum pressures ranging between 0.20 and 0.30 MPa. Those microbubbles are generally used as ultrasonic contrast agent and they are evacuated very rapidly from the system through the lungs and kidneys (half-life time in humans: 5-10 minutes typically).…”

Non-human primate skull effects on the cavitation detection threshold of FUS-induced blood-brain barrier opening

“…A polyacrylamide phantom with a channel of 4 mm in diameter was made to contain the in-house manufactured lipid-shelled monodisperse MB with a gas core of perfluorobutane (median diameter: 4-5 μm, concentration: 1×10 9 bubbles/mL) 13 , and the 4-mm channel was chose to include the -6 dB focus of the transducer. A single-element FUS transducer was applied (center frequency or fc: 500 kHz, focal length: 62.6 mm, focal width and depth in -6 dB: 5.85 mm and 34 mm) with a flat-band hydrophone (sensitivity: 0.01-15 MHz) at the center (Sonic Concepts Inc., WA, USA) served as PCD.…”

Monodisperse bubbles and droplets for medical applications

“…b) Bubbles can be sorted using the difference in gravitational force acting on bubbles of different size. Centrifugation of the bubble suspension can be applied to increase the efficiency of this sorting technique 83 . c) The buoyancy force can also be used through decantation 82,87 , the larger bubbles rise faster in a fluid than the smaller bubbles.…”

“…by filtering 79 or by decantation 82 . A selection of bubbles can also be extracted by means of centrifugation 83 or by using a microfluidic sorting strategy, e.g. using pinched flow fractionation 84 .…”

“…The basis of this procedure is that gravitational forces are balanced by viscous drag forces; larger bubbles rise faster in the fluid due to a larger buoyant force although in practice this is not a well-controlled process. Similarly, Feshitan et al 83 isolate size fractions from a polydisperse UCA by centrifuging the suspension. A cylinder with the agent is rotated at high speed after which the bubbles were extracted from the cylinder at certain heights.…”