A microfluidic system combining acoustic and dielectrophoretic particle preconcentration and focusing

Microfabricated systems have recently become useful for routing particles to precise locations in microfluidic channels. In this paper we discuss the modeling, fabrication and characterization of such a platform that combines acoustic forces and ac dielectrophoresis (DEP). This system integrates a bulk lead zirconate titanate (PZT) slab with substrate patterned microelectrodes for DEP manipulation of particles. Moreover, a one-dimensional transmission line model is presented to understand the coupling of the acoustic and dielectrophoretic transducers with the microdevice. While the acoustic model does not predict the lateral coupling in the system, it does provide some insight into axial (thickness-mode) frequencies of operation. Experiments are also conducted in which particles were routed into a large (0.75 mm wide) microchannel and preconcentrated and focused into coarse bundles by coupling an acoustic wave into the channel. Subsequently, particles are further focused into single file particle streams using interdigitated DEP electrodes. This system can be used for high throughput assays for which it is necessary to isolate and investigate small bundles of particles and single particles.

[1]  T. Laurell,et al.  Continuous separation of lipid particles from erythrocytes by means of laminar flow and acoustic standing wave forces. , 2005, Lab on a chip.

[2]  H. Watarai,et al.  Dielectrophoresis of microbioparticles in water with planar and capillary quadrupole electrodes. , 2003, IEE proceedings. Nanobiotechnology.

[3]  J.-L. Dion.  New transmission line analogy applied to single and multilayered piezoelectric transducers , 1993, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[4]  J Dual,et al.  Micro-manipulation of small particles by node position control of an ultrasonic standing wave. , 2002, Ultrasonics.

[5]  H M Hertz,et al.  Ultrasonic standing wave manipulation technology integrated into a dielectrophoretic chip. , 2006, Lab on a chip.

[6]  Conrad D. James,et al.  A Microfabricated Flow Cytometry System for Optical Detection of Cellular Parameters. , 2007 .

[7]  P. Svasek,et al.  Optimization of microfluidic particle sorters based on dielectrophoresis , 2005, IEEE Sensors Journal.

[8]  Jeremy J. Hawkes,et al.  Force field particle filter, combining ultrasound standing waves and laminar flow , 2001 .

[9]  Igal Brener,et al.  Microfluidics and Microacoustics for Miniature Flow Cytometry. , 2007 .

[10]  A. B. Frazier,et al.  A micro system using dielectrophoresis and electrical impedance spectroscopy for cell manipulation and analysis , 2003, TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664).

[11]  H Morgan,et al.  On-chip high-speed sorting of micron-sized particles for high-throughput analysis. , 2005, IEE proceedings. Nanobiotechnology.

[12]  Thomas Laurell,et al.  Acoustic control of suspended particles in micro fluidic chips. , 2004, Lab on a chip.

[13]  Hywel Morgan,et al.  High throughput particle analysis: combining dielectrophoretic particle focussing with confocal optical detection. , 2006, Biosensors & bioelectronics.

[14]  K. Agbossou,et al.  Exact one-dimensional computation of ultrasonic transducers with several piezoelectric elements and passive layers using the transmission line analogy , 1997, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[15]  J. Hawkes,et al.  Analytical scale ultrasonic standing wave manipulation of cells and microparticles. , 2000, Ultrasonics.

[16]  Neil M. White,et al.  A silicon microfluidic ultrasonic separator , 2003 .

[17]  R. Krimholtz,et al.  New equivalent circuits for elementary piezoelectric transducers , 1970 .

[18]  J Dual,et al.  Positioning of small particles by an ultrasound field excited by surface waves. , 2004, Ultrasonics.

[19]  Thomas B. Jones,et al.  Electromechanics of Particles , 1995 .

[20]  N. White,et al.  Investigation of two-dimensional acoustic resonant modes in a particle separator. , 2006, Ultrasonics.

[21]  Hywel Morgan,et al.  Dielectrophoretic investigations of sub-micrometre latex spheres , 1997 .

[22]  Thomas Laurell,et al.  Trapping of microparticles in the near field of an ultrasonic transducer. , 2005, Ultrasonics.

[23]  Thomas Laurell,et al.  Carrier medium exchange through ultrasonic particle switching in microfluidic channels. , 2005, Analytical chemistry.