Dielectrophoretic separation of bacteria using a conductivity gradient

Markx, Gerard H.; Dyda, Penelope A.; Pethig, Ronald

doi:10.1016/0168-1656(96)01617-3

Cited by 183 publications

(114 citation statements)

References 9 publications

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“…This ultimately compromises device throughput as opposed to 2D iDEP and eDEP devices that have been reported to operate at high flow rates. 32,33 The 3D pDEP throughput could be readily enhanced by aligning channels in parallel or increasing the channel depth and width dimensions. Consequently, the trapping efficiency deteriorated from here onwards.…”

Section: Flow Rate Analysismentioning

confidence: 99%

Three dimensional passivated-electrode insulator-based dielectrophoresis

et al. 2015

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In this study, a 3D passivated-electrode, insulator-based dielectrophoresis microchip (3D pDEP) is presented. This technology combines the benefits of electrodebased DEP, insulator-based DEP, and three dimensional insulating features with the goal of improving trapping efficiency of biological species at low applied signals and fostering wide frequency range operation of the microfluidic device. The 3D pDEP chips were fabricated by making 3D structures in silicon using reactive ion etching. The reusable electrodes are deposited on second glass substrate and then aligned to the microfluidic channel to capacitively couple the electric signal through a 100 lm glass slide. The 3D insulating structures generate high electric field gradients, which ultimately increases the DEP force. To demonstrate the capabilities of 3D pDEP, Staphylococcus aureus was trapped from water samples under varied electrical environments. Trapping efficiencies of 100% were obtained at flow rates as high as 350 ll/h and 70% at flow rates as high as 750 ll/h. Additionally, for live bacteria samples, 100% trapping was demonstrated over a wide frequency range from 50 to 400 kHz with an amplitude applied signal of 200 Vpp. 20% trapping of bacteria was observed at applied voltages as low as 50 Vpp. We demonstrate selective trapping of live and dead bacteria at frequencies ranging from 30 to 60 kHz at 400 Vpp with over 90% of the live bacteria trapped while most of the dead bacteria escape. V C 2015 AIP Publishing LLC.

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Section: Flow Rate Analysismentioning

confidence: 99%

Three dimensional passivated-electrode insulator-based dielectrophoresis

et al. 2015

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“…One demonstration, from Peter Gascoyne's group at MD Anderson Cancer Center, showed the technique could separate cancer cells spiked into human blood, potentially marking it out as a prognostic technique for the detection of circulating tumor cells; 24 the second, by the Pethig lab at Bangor, where CD34þ hematopoietic stem cells were separated from bone marrow. 25 By this point-30 years after the first demonstration of DEP separation-what could be regarded as the key separation targets in DEP had already been demonstrated; cancer cells from blood, 24 stem cells, 25,26 bacteria of different strains 27,28 and live and dead cells. 2 One final implementation of DEP separation has endured from this period.…”

Section: The Microfabrication Explosionmentioning

confidence: 99%

Fifty years of dielectrophoretic cell separation technology

Hughes

2016

Biomicrofluidics

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In 1966, Pohl and Hawk [Science 152, 647–649 (1966)] published the first demonstration of dielectrophoresis of living and dead yeast cells; their paper described how the different ways in which the cells responded to an applied nonuniform electric field could form the basis of a cell separation method. Fifty years later, the field of dielectrophoretic (DEP) cell separation has expanded, with myriad demonstrations of its ability to sort cells on the basis of differences in electrical properties without the need for chemical labelling. As DEP separation enters its second half-century, new approaches are being found to move the technique from laboratory prototypes to functional commercial devices; to gain widespread acceptance beyond the DEP community, it will be necessary to develop ways of separating cells with throughputs, purities, and cell recovery comparable to gold-standard techniques in life sciences, such as fluorescence- and magnetically activated cell sorting. In this paper, the history of DEP separation is charted, from a description of the work leading up to the first paper, to the current dual approaches of electrode-based and electrodeless DEP separation, and the path to future acceptance outside the DEP mainstream is considered.

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“…3,5,6 The manipulation of small particles using dielectrophoresis and ac electrokinetic techniques in general has recently received considerable attention as an alternative to optical tweezers 7,8 or scanning probe techniques, 9,10 and is becoming a useful tool in molecular biology and biotechnology. Dielectrophoretic forces have been used to separate and manipulate cells, 2,11 bacteria, 12,13 viruses, 14 and submicron latex spheres. 5,15,16 Recently the dielectrophoretic manipulation of DNA molecules has led to applications such as the concentration of DNA molecules, [17][18][19] DNA-protein interaction studies, 20,21 and molecular surgery of DNA.…”

Section: Introductionmentioning

confidence: 99%

Influence of alternating current electrokinetic forces and torque on the elongation of immobilized DNA

Germishuizen

Tosch

Middelberg

et al. 2004

Journal of Applied Physics

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Articles you may be interested inThe authors investigate the elongation and orientation of different-sized deoxyribose nucleic acid (DNA) molecules, tethered onto gold electrodes via a terminal thiol, under the influence of high frequency ac electric fields. The DNA molecules are elongated from a random coil into an extended conformation and orientated along the electric field lines as a result of the forces acting on the molecules during the application of the ac electric fields. Elongation was observed in the frequency range 100 kHz-1 MHz, with field strengths of 0.06-1.0 MV/ m. Maximum elongation for all DNA fragments tested, irrespective of size, was found for frequencies between 200 and 300 kHz. The torque acting on the induced dipole in the DNA molecules, complemented by a directional bias force, opposite in direction to the dielectrophoretic force, provides the main contribution to the elongation process. The length of elongation is limited to either half the distance between opposing electrodes or to the contour length of the DNA, whichever is shorter. Further, the authors show that the normalized length of the elongated DNA molecules is independent of the contour length of the DNA.

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Dielectrophoretic separation of bacteria using a conductivity gradient

Cited by 183 publications

References 9 publications

Three dimensional passivated-electrode insulator-based dielectrophoresis

Three dimensional passivated-electrode insulator-based dielectrophoresis

Fifty years of dielectrophoretic cell separation technology

Influence of alternating current electrokinetic forces and torque on the elongation of immobilized DNA

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