Hydrodynamic focusing with a microlithographic manifold: controlling the vertical position of a focused sample

Kennedy, Matthew J.; Stelick, Scott; Perkins, Sasha L.; Li, Cao; Batt, Carl A.

doi:10.1007/s10404-009-0417-6

Cited by 17 publications

(19 citation statements)

References 22 publications

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“…The microfluidic device includes a hydrodynamic focusing architecture described in detail in our previous work 32 with a newly added extending microfluidic channel as illustrated in Figure 1. The microchannel length equals 120 widths, and its explicit dimensions are 125 lm Â 125 lm Â 16 000 lm.…”

Section: A Microfluidic Devicementioning

confidence: 99%

“…The volumetric rate of sheath solution to core solution, SCR ¼ (2U 2 þ 2U 3 )/U 1 , determines the initial girth of the core solution. Previous work highlights additional capabilities of this manifold including its ability to maneuver, the focused core up and down within the microchannel 32 and its ability to squeeze and expand the focused core. 33 Control of mean liquid velocity requires co-adjustment to the ratio of upper and lower sheath flow-rates in order to maintain the position of the core fixed at the center-depth of the microchannel.…”

Section: A Microfluidic Devicementioning

confidence: 99%

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Analysis of a laminar-flow diffusional mixer for directed self-assembly of liposomes

et al. 2012

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The present work describes the operation and simulation of a microfluidic laminarflow mixer. Diffusive mixing takes place between a core solution containing lipids in ethanol and a sheath solution containing aqueous buffer, leading to self assembly of liposomes. Present device architecture hydrodynamically focuses the lipid solution into a cylindrical core positioned at the center of a microfluidic channel of 125 Â 125-lm 2 cross-section. Use of the device produces liposomes in the size range of 100-300 nm, with larger liposomes forming at greater ionic strength in the sheath solution and at lower lipid concentration in the core solution. Finite element simulations compute the concentration distributions of solutes at axial distances of greater than 100 channel widths. These simulations reduce computation time and enable computation at long axial distances by utilizing long hexahedral elements in the axial flow region and fine tetrahedral elements in the hydrodynamic focusing region. Present meshing technique is generally useful for simulation of long microfluidic channels and is fully implementable using COMSOL Multiphysics. Confocal microscopy provides experimental validation of the simulations using fluorescent solutions containing fluorescein or enhanced green fluorescent protein.

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Section: A Microfluidic Devicementioning

confidence: 99%

Section: A Microfluidic Devicementioning

confidence: 99%

Analysis of a laminar-flow diffusional mixer for directed self-assembly of liposomes

et al. 2012

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“…Three-dimensional focusing has been accomplished hydrodynamically using bas-relief structures, 16 inertial vortices, 12,17 and multi-layer manifolds. 18,19 An advantage of the multi-layer manifolds is their capability of out-of-plane steering of the focused stream. 19 …”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic optical alignment for microflow cytometry

et al. 2011

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A microfabricated flow cytometer has been developed that is capable of detecting nearly all of the microparticles in an aqueous suspension. Current design allows for integrated coupling between an optical fiber-based detection system and the particle stream via hydrodynamic focusing. By adjusting the relative flow-rates at the auxiliary inputs of the focusing manifold, the particle stream can be steered out-of-plane relative to the illuminating laser, and similarly the particle stream can be squeezed or expanded. The microfabricated device was constructed in polydimethylsiloxane with cross-sectional microfluidic dimensions of 125 μm × 125 μm. Using the present device and method, fluorescent microparticles in aqueous solution were counted at an absolute counting efficiency of 91 ± 4%. The coefficient of variation of the fluorescence pulse-heights for far-red fluorescent microparticles was 15%. The device exhibited a linear response to fluorescence intensity calibration microparticles as shown by comparison with a commercial cytometer instrument.

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“…The glue was cured by the UV light to form a dam at the end of the capillary/fiber. Kennedy et al [16], [17] fabricated a hydrodynamic flow cell with fiber insertion guides. This technique required a contact aligner to bond two patterned pieces of PDMS.…”

Section: Introductionmentioning

confidence: 99%

A Spectroscopic Technique for Local Temperature Measurement in a Micro-Optofluidic System

et al. 2016

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• A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publicationGeneral rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. Abstract-We present a spectroscopy technique to measure temperature locally in a polydimethylsiloxane (PDMS) microoptofluidic chip with integrated optical fibers and minimal optical components. The device was fabricated in one step with fiber coupler grooves followed by manual integration of the optical fibers. The experimental setup consists of a microoptofluidic chip with a pair of optical fibers for excitation and fluorescence collection, a laser module and a spectrometer. The laser module is coupled to one of the optical fibers to guide the light into the microchannel. The fluorescence signal is collected by a second integrated optical fiber placed orthogonally. A spectroscopy technique is used to measure the local temperature in a microchannel (500 µm wide and 125 µm in height) using Rhodamine B as a temperature indicator. It is shown that for a flow rate between 200 and 400 μL/min, the local temperature can be determined.

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Hydrodynamic focusing with a microlithographic manifold: controlling the vertical position of a focused sample

Cited by 17 publications

References 22 publications

Analysis of a laminar-flow diffusional mixer for directed self-assembly of liposomes

Analysis of a laminar-flow diffusional mixer for directed self-assembly of liposomes

Hydrodynamic optical alignment for microflow cytometry

A Spectroscopic Technique for Local Temperature Measurement in a Micro-Optofluidic System

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