Ultrasonic deposition of cells on a surface

Hawkes, Jeremy J.; Long, Michael J.; Coakley, W. Terence; McDonnell, Martin B.

doi:10.1016/j.bios.2003.10.003

Cited by 81 publications

(53 citation statements)

References 19 publications

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“…Some related devices rely on a separate spacer layer to define the fluid layer depth and use a seal to form the side-walls [8,9]. In these devices, lateral forces do not appear to be as significant.…”

Section: Influence Of Side-wall Materialsmentioning

confidence: 99%

Investigation of two-dimensional acoustic resonant modes in a particle separator

et al. 2006

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Within an acoustic standing wave particles experience acoustic radiation forces, a phenomenon which is exploited in particle or cell manipulation devices. When developing such devices, one-dimensional acoustic characteristics corresponding to the transducer(s) are typically of most importance and determine the primary radiation forces acting on the particles. However, radiation forces have also been observed to act in the lateral direction, perpendicular to the primary radiation force, forming striated patterns. These lateral forces are due to lateral variations in the acoustic field influenced by the geometry and materials used in the resonator. The ability to control them would present an advantage where their effect is either detrimental or beneficial to the particle manipulation process.The two-dimensional characteristics of an ultrasonic separator device have been modelled within a finite element analysis (FEA) package. The fluid chamber of the device, within which the standing wave is produced, has a width to height ratio of approximately 30:1 and it is across the height that a half-wavelength standing wave is produced to control particle movement. Two-dimensional modal analyses have calculated resonant frequencies which agree well with both the one-dimensional modelling of the device and experimentally measured frequencies. However, these two-dimensional analyses also reveal that these modes exhibit distinctive periodic variations in the acoustic pressure field across the width of the fluid chamber. Such variations lead to lateral radiation forces forming particle bands (striations) and are indicative of enclosure modes.The striation spacings predicted by the FEA simulations for several modes compare well with those measured experimentally for the ultrasonic particle separator device. It is also shown that device geometry and materials control enclosure modes and therefore the strength and characteristics of lateral radiation forces, suggesting the potential use of FEA in designing for the control of enclosure modes in similar particle manipulator devices.

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Section: Influence Of Side-wall Materialsmentioning

confidence: 99%

Investigation of two-dimensional acoustic resonant modes in a particle separator

et al. 2006

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“…[30,31] In addition to cavitation, researchers have exploited ultrasonic radiation forces to enhance targeted delivery of nanoparticles or microbubbles through contact-mediated mechanisms. [32,33] Several reviews summarizing biological applications of physical or mechanical effects of ultrasound have been published. [34][35][36] There is a sizable literature exploring ultrasonically induced release from nanoscale delivery vehicles such as liposomes and polymeric micelles.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonically Induced Release from Nanosized Polymer Vesicles

Pangu

Davis

Bates

et al. 2010

Macromolecular Bioscience

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Vesicles made from synthetic diblock copolymers, polymersomes, have great potential for targeted imaging and drug delivery. Ultrasound is gaining attention as a therapeutic tool in addition to its use in diagnostics. We report on the response of nanoscale vesicles made from PEO-b-PBD copolymers to ultrasound at 20 kHz. Leakage of a fluorescent dye from vesicle core was measured to study the permeation. Ultrasound causes significant leakage from the core above threshold intensity, suggesting that leakage is governed by acoustic cavitation. Size measurements and direct visualization of vesicles show that ultrasound does not completely rupture them into fragments but causes transient poration. The extent of leakage inversely depends on membrane thickness and directly depends on sonication time and intensity.

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“…These particles will typically migrate towards the acoustic pressure node whereby it is possible to form a concentrate. This phenomenon has applications in the handling of biosamples and bio-sensing techniques [3,4] where the sensitivity of a detector depends heavily on the population of events or bio-matter contacting the sensor element or in the detector region. Where particles, cells or spores are of interest, one method to increase the sensitivity of their detection is to concentrate the particles prior to the detection stage.…”

Section: Introductionmentioning

confidence: 99%

“…To achieve this, acoustic radiation forces are used to move particles close to a surface where the concentrated particle stream is selectively drawn off. This operation relies on the generation of a quarter-wavelength standing wave which has previously been used to transport particles to a surface [4,5] and has paved the way for this study. This previous work has tended to focus on batch processing of a sample (as opposed to continuous flow) and movement of particles up to the surface such that they become adhered to it, ideally where a sensing element is incorporated into the surface.…”

Section: Introductionmentioning

confidence: 99%

Performance of a quarter-wavelength particle concentrator

et al. 2008

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a b s t r a c tA series of devices have been investigated which use acoustic radiation forces to concentrate micron sized particles. These multi-layered resonators use a quarter-wavelength resonance in order to position an acoustic pressure node close to the top surface of a fluid layer such that particles migrate towards this surface. As flow-through devices, it is then possible to collect a concentrate of particulates by drawing off the particle stream and separating it from the clarified fluid and so can operate continuously as opposed to batch processes such as centrifugation. The methods of construction are described which include a micro-fabricated, wet-etched device and a modular device fabricated using a micro-mill. These use silicon and macor, a machinable glass ceramic, as a carrier layer between the transducer and fluid channel, respectively. Simulations using an acoustic impedance transfer model are used to determine the influence of various design parameters on the acoustic energy density within the fluid layer and the nodal position. Concentration tests have shown up to 4.4-, 6.0-and 3.2-fold increases in concentration for 9, 3 and 1 lm diameter polystyrene particles, respectively. The effect of voltage and fluid flow rates on concentration performance is investigated and helps demonstrate the various factors which determine the increase in concentration possible.

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Ultrasonic deposition of cells on a surface

Cited by 81 publications

References 19 publications

Investigation of two-dimensional acoustic resonant modes in a particle separator

Investigation of two-dimensional acoustic resonant modes in a particle separator

Ultrasonically Induced Release from Nanosized Polymer Vesicles

Performance of a quarter-wavelength particle concentrator

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