An insulator-based dielectrophoretic microdevice for the simultaneous filtration and focusing of biological cells

Jen, Chun-Ping; Chen, Wei-Fu

doi:doi:10.1063/1.3658644

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Transportation of single cell and microbubbles by phase-shift introduced to standing leaky surface acoustic waves

A microfluidic device was developed to precisely transport a single cell or multiple microbubbles by introducing phase-shifts to a standing leaky surface acoustic wave (SLSAW). The device consists of a polydimethyl-siloxane (PDMS) microchannel and two phase-tunable interdigital transducers (IDTs) for the generation of the relative phase for the pair of surface acoustic waves (SAW) propagating along the opposite directions forming a standing wave. When the SAW contacts the fluid medium inside th...

Simulation of conformational preconditioning strategies for electrophoretic stretching of DNA in a microcontraction

We have used Brownian dynamics-finite element method to examine two conformational preconditioning approaches for improving DNA stretching in a microcontraction for the purpose of direct gene analysis. The newly proposed “pre-stretching” strategy is found to significantly improve the degree of DNA extension at the exit of the contraction. On the other hand, applying an oscillating extensional field to DNA yields no preconditioning effect. Detailed analysis of the evolution of DNA extension and ...

Manipulating and discriminating biological cells of interest using microfluidic and micro total analysis system (μTAS) devices have potential applications in clinical diagnosis and medicine. Cellular focusing in microfluidic devices is a prerequisite for medical applications, such as cell sorting, cell counting, or flow cytometry. In the present study, an insulator-based dielectrophoretic microdevice is designed for the simultaneous filtration and focusing of biological cells. The cells are introduced into the microchannel and hydrodynamically pre-confined by funnel-shaped insulating structures close to the inlet. There are ten sets of X-patterned insulating structures in the microfluidic channel. The main function of the first five sets of insulating structures is to guide the cells by negative dielectrophoretic responses (viable HeLa cells) into the center region of the microchannel. The positive dielectrophoretic cells (dead HeLa cells) are attracted to regions with a high electric-field gradient generated at the edges of the insulating structures. The remaining five sets of insulating structures are mainly used to focus negative dielectrophoretic cells that have escaped from the upstream region. Experiments employing a mixture of dead and viable HeLa cells are conducted to demonstrate the effectiveness of the proposed design. The results indicate that the performance of both filtration and focusing improves with the increasing strength of the applied electric field and a decreasing inlet sample flow rate, which agrees with the trend predicted by the numerical simulations. The filtration efficiency, which is quantitatively investigated, is up to 88% at an applied voltage of 50 V peak-to-peak (1 kHz) and a sample flow rate of 0.5 μl/min. The proposed device can focus viable cells into a single file using a voltage of 35 V peak-to-peak (1 kHz) at a sample flow rate of 1.0 μl/min.

Article Outline

INTRODUCTION
THEORY AND DESIGN
EXPERIMENTAL SECTION
1. Chip fabrication
2. Cell treatment
3. Apparatus
RESULTS AND DISCUSSION
CONCLUSION

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KEYWORDS and PACS

Keywords

bioelectric potentials, biological fluid dynamics, bioMEMS, cellular transport, electrophoresis, hydrodynamics, insulators, microchannel flow, patient diagnosis

PACS

87.85.Ox

Biomedical instrumentation and transducers, including micro-electro-mechanical systems (MEMS)
47.63.mh

Transport processes and drug delivery
85.85.+j

Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
87.17.-d

Cell processes
47.60.Dx

Flows in ducts and channels
87.80.Kc

Electrochemical techniques

ARTICLE DATA

Digital Object Identifier

http://dx.doi.org/10.1063/1.3658644

PUBLICATION DATA

ISSN

1932-1058 (online)

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$abstract.society.value is a Member of CrossRef

American Institute of Physics

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