Micromachined membrane particle filters

Yang, Xing; Yang, Joon Mo; Tai, Yu‐Chong; Ho, Chih‐Ming

doi:10.1016/s0924-4247(98)00269-6

Cited by 93 publications

(32 citation statements)

References 6 publications

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“…A passive alternative to active forces is the integration of geometric features such as obstacles and side channels into the microfluidic network. [24][25][26] Particle sensitivity is less obvious here, but sizedependent, directional and selective transports of particles and cells in controlled fashion can be achieved in such setups as well. 27,28 Usually, this requires the introduction of very small structural elements on the order of the particle size.…”

Section: Introductionmentioning

confidence: 99%

“…27,28 Usually, this requires the introduction of very small structural elements on the order of the particle size. [24][25][26][27][28] Microbubbles, with a size of tens to hundred microns, have been used as powerful actuating elements for microfluidic applications in various contexts. [29][30][31][32][33][34] Cyclic generation, growth and collapse of vapor bubbles from thermal heating can pump liquid.…”

Section: Introductionmentioning

confidence: 99%

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Efficient manipulation of microparticles in bubble streaming flows

Wang

Jalikop

Hilgenfeldt³

2012

Biomicrofluidics

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Oscillating microbubbles of radius 20-100 lm driven by ultrasound initiate a steady streaming flow around the bubbles. In such flows, microparticles of even smaller sizes (radius 1-5 lm) exhibit size-dependent behaviors: particles of different sizes follow different characteristic trajectories despite density-matching. Adjusting the relative strengths of the streaming flow and a superimposed Poiseuille flow allows for a simple tuning of particle behavior, separating the trajectories of particles with a size resolution on the order of 1 lm. Selective trapping, accumulation, and release of particles can be achieved. We show here how to design bubble microfluidic devices that use these concepts to filter, enrich, and preconcentrate particles of selected sizes, either by concentrating them in discrete clusters (localized both stream-and spanwise) or by forcing them into narrow, continuous trajectory bundles of strong spanwise localization.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Efficient manipulation of microparticles in bubble streaming flows

Wang

Jalikop

Hilgenfeldt³

2012

Biomicrofluidics

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“…However, the pressure drop could also be significant to adversely affect the liquid flow or even to break the membranes as the trap opening becomes smaller. The robustness of the membrane also depends on the opening factors as well as the pore dimension [25]. Figure 2A shows the schematic illustration of the fabrication process of pore-type iDEP chips.…”

Section: Principles Of Idepmentioning

confidence: 99%

Bacteria concentration using a membrane type insulator‐based dielectrophoresis in a plastic chip

et al. 2009

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We report an insulator-based (or, electrodeless) dielectrophoresis utilizing microfabricated plastic membranes. The membranes with honeycomb-type pores have been fabricated by patterning the SU-8 layer on a substrate which was pretreated with self-assembled monolayer of octadecyltrichlorosilane for the easy release. The fabricated membrane was positioned between two electrodes and alternating current field was applied for the particle trap experiments. The particle could be trapped due to the dielectrophoresis force generated by the non-uniformities of the electric fields applied through the membranes with pores. Simulations using CFD-ACE+(CFD Research, Huntsville, Alabama) suggested that the dielectrophoresis force is stronger in the edge of the pores where the field gradient is highest. The bacteria could be captured on the near edge of the pores when the electric field was turned on and the trapped bacteria could be released when the field was turned off with the release efficiency of more than 93+/-7%. The maximal trapping efficiency of 66+/-7% was obtained under the electric fields (E=128 V/mm and f=300 kHz) when the dilute bacteria solution (Escherichia coli: 9.3 x 10(3) cell/mL, 0.5 mS/m) flowed with a flow rate of 100 microL/min.

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“…High-aspect-ratio micro and nano structures are key components for various microscale devices and systems, such as MEMS and mTAS [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. For example, ordered arrays of uniform pores are applicable to micro-channels for micro-fluidic and filtering devices [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…For example, ordered arrays of uniform pores are applicable to micro-channels for micro-fluidic and filtering devices [5][6][7]. Microscale tube and chamber structures are also required for micro reactors [8][9].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of high-aspect-ratio arrayed structures using Si electrochemical etching

Sato

Homma

2006

Science and Technology of Advanced Materials

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This paper reviews microscale processes to fabricate three-dimensional structures, in particular, high-aspect-ratio arrayed structures, using precise electrochemical etching process. Array of sharp micropits were pre-formed on the front side surface of Si wafer and the electrochemical etching was carried out using aqueous HF solution, with the back side illumination to generate holes, which diffused to the edge of the micropits to proceed the dissolution of Si with fluoride species. In order to form high-aspect-ratio pores at selected areas, a shade mask pattern was fabricated on the back side surface to align the illumination to the pre-patterned area on the front side surface. The parameters, such as HF concentration, current density and hole diffusion length, were optimized and uniform array of straight pores was formed into the designed area of Si wafer.Subsequently the surface of the pores was thermally oxidized to form SiO 2 layers, and arrayed glass tubes with picoliter volume were fabricated. On the other hand, the pore filling with metal was attempted using electrodeposition to obtain array of the metal needles. For this, the ''single batch'' process was developed to form the pore array and metal filling with single electrolyte, and array of metal micro needles was successfully formed. These processes demonstrated capability and possibility of the electrochemical processes for microscale fabrication, and further precise processes can be developed using these approaches. r

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Micromachined membrane particle filters

Cited by 93 publications

References 6 publications

Efficient manipulation of microparticles in bubble streaming flows

Efficient manipulation of microparticles in bubble streaming flows

Bacteria concentration using a membrane type insulator‐based dielectrophoresis in a plastic chip

Fabrication of high-aspect-ratio arrayed structures using Si electrochemical etching

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