Separation devices based on forced coincidence response of fluid-filled pipes

We investigated the potential damage inflicted on erythrocytes by acoustic radiation force when the cells are concentrated by a 500-kHz ultrasonic standing wave at the pressure node. The extent of the damage was estimated from the concentrations of potassium ions, iron complexes, and lactate dehydrogenase released from the cells. After 2 min of ultrasound irradiation at 12.8 mJ/m3, the cells concentrated on the pressure node, with a cell distribution half-width of 138 microns; no significant release of intracellular components was detected, even after 15 min of irradiation. The results indicate that even small ions like potassium are not released as a result of ultrasound irradiation on cell membranes without cavitation, and they demonstrate the potential use of acoustic radiation force for concentrating living cells in biomedical applications.

Section: Introductionmentioning

confidence: 99%

Using acoustic radiation force as a concentration method for erythrocytes

Yasuda

Haupt

Umemura

et al. 1997

“…The theoretical framework has been developed by King, 3 Yosioka and Kawasima, 4 Gor'kov, 5 and Tolt and Feke. 6,7 They developed a separation process based on the acoustic radiation force in a stationary ultrasonic standing wave field. Tolt and Feke 6 used a frequency sweeping method to translate the concentrated particles across the resonator.…”

Section: Introductionmentioning

confidence: 99%

Separation of bacterial spores from flowing water in macro-scale cavities by ultrasonic standing waves.

Lipkens

Dionne

Costolo

et al. 2010

The separation of micron-sized bacterial spores (Bacillus cereus) from a steady flow of water through the use of ultrasonic standing waves is demonstrated. An ultrasonic resonator with cross-section of 0.0254 m x 0.0254 m has been designed with a flow inlet and outlet for a water stream that ensures laminar flow conditions into and out of the resonator section of the flow tube. A 0.01905-m diameter PZT-4, nominal 2-MHz transducer is used to generate ultrasonic standing waves in the resonator. The acoustic resonator is 0.0356 m from transducer face to the opposite reflector wall with the acoustic field in a direction orthogonal to the water flow direction. At fixed frequency excitation, spores are concentrated at the stable locations of the acoustic radiation force and trapped in the resonator region. The effect of the transducer voltage and frequency on the efficiency of spore capture in the resonator has been investigated. Successful separation of B. cereus spores from water with typical volume flow rates of 40-250 ml/min has been achieved with 15% efficiency in a single pass at 40 ml/min.

“…King [6], Yosioka and Kawasima [7], Gor'kov, [8] and others developed the fundamental theories of the acoustic radiation force. Of interest to our current efforts is the work by Tolt and Feke [9], [10]. They developed a separation process based on the acoustic radiation force in a stationary ultrasonic standing wave field.…”

Section: Introductionmentioning

confidence: 99%

Frequency sweeping and fluid flow effects on particle trajectories in ultrasonic standing waves

Lipkens

Dionne

Costolo

et al. 2008

Particle concentration in ultrasonic standing waves by the acoustic radiation force is discussed. The acoustic radiation force is a function of the density and compressibility of the fluid and the suspended particles. A twodimensional theoretical model is developed for particle trajectory calculations. An electro-acoustic model is used to predict the acoustic field in a resonator. The results of the linear acoustic model are used to calculate the acoustic radiation force acting on a particle suspended in the resonator. A particle trajectory model is developed that integrates the equation of motion of a particle subjected to a buoyancy force, a fluid drag force, and the acoustic radiation force. Computational fluid dynamics simulations are performed to calculate the velocity field. For a fixed frequency excitation, the particles are concentrated along the stable node locations of the acoustic radiation force. Through a periodic sweeping of the excitation frequency particle translation is achieved. Two types of frequency sweeps are considered, a ramp approach and a step-change method. Numerical results of particle trajectory calculations in a resonator with dimensions much larger than a typical wavelength are presented. Experimental observations of particle concentration of 6 μm polystyrene spheres are presented.