Microfabricated devices in biotechnology and biochemical processing

Joule heating is a significant problem in electrokinetically driven microfluidic chips, particularly polymeric systems where low thermal conductivities amplify the difficulty in rejecting this internally generated heat. In this work, a combined experimental (using a microscale thermometry technique) and numerical (using a 3D "whole-chip" finite element model) approach is used to examine Joule heating and heat transfer at a microchannel intersection in poly(dimethylsiloxane) (PDMS), and hybrid PDMS/Glass microfluidic systems. In general the numerical predictions and the experimental results agree quite well (typically within ± 3 °C), both showing dramatic temperature gradients at the intersection. At high potential field strengths a nearly five fold increase in the maximum buffer temperature was observed in the PDMS/PDMS chips over the PDMS/Glass systems. The detailed numerical analysis revealed that the vast majority of steady state heat rejection is through lower substrate of the chip, which was significantly impeded in the former case by the lower thermal conductivity PDMS substrate. The observed higher buffer temperature also lead to a number of significant secondary effects including a near doubling of the volume flow rate. Simple guidelines are proposed for improving polymeric chip design and thereby extend the capabilities of these microfluidic systems.

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“…(1) and for the boundary condition on eqn. (6) and again solved within the fluidic domain, is described by eqn.…”

Section: Fluidic Analysismentioning

confidence: 99%

Joule heating and heat transfer in poly(dimethylsiloxane) microfluidic systems

2003

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“…Photolithography offers great flexibility in channel design [11,38,39] and gives the option to fabricate a variety of different functional units such as microunit-operation blocks [62] and integrated pumping, mixing, and filtering devices [63].…”

Section: Removal Of the Oxide Layer (If Necessary)mentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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There is a great demand in separation technologies for faster and more effective analysis processes. Miniaturization is a suitable technique for satisfying this demand as reduction in size gives increased separation speed with higher efficiency. CEC is an electric-field-mediated separation technique where the liquid flow is generated by the electric field itself. The main advantage of using electric field over pressure for flow generation is the flat flow profile of the EOF; thus, CEC is one of the best candidates to construct a novel and high-efficiency microanalytical device. The aim of the present paper is to review the basic fabrication and bonding principles, as well as connection and system integration options for microfluidics-based electrochromatography. The physical structure and fluidic channel formation are critically evaluated, including glass microstructuring and fusion bonding. Recent developments in nanoflow measurements and the application of various flow control units are also extensively discussed.

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“…This allows for quick and inexpensive device construction. Third, using chip-based fabrication can extend the device's capabilities by permitting either future integration of our measurement with other microfluidic components (22,23) such as separation units or mixers, or construction of arrays of sensors on a single chip for performing many measurements or assays in parallel. Fig.…”

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confidence: 99%

Direct detection of antibody–antigen binding using an on-chip artificial pore

Saleh

Sohn

2003

Proc. Natl. Acad. Sci. U.S.A.

166

128

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We demonstrate a rapid and highly sensitive all-electronic technique based on the resistive pulse method of particle sizing with a pore to detect the binding of unlabeled antibodies to the surface of latex colloids. Here, we use an on-chip pore to sense colloids derivatized with streptavidin and measure accurately their diameter increase on specific binding to several different types of antibodies. We show the sensitivity of this technique to the concentration of free antibody and that it can be used to perform immunoassays in both inhibition and sandwich configurations. Overall, our technique does not require labeling of the reactants and is performed rapidly by using very little solution, and the pore itself is fabricated quickly and inexpensively by using soft lithography. Finally, because this method relies only on the volume of bound ligand, it can be generally applied to detecting a wide range of ligand-receptor binding reactions.

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Microfabricated devices in biotechnology and biochemical processing

Cited by 208 publications

References 38 publications

Joule heating and heat transfer in poly(dimethylsiloxane) microfluidic systems

Joule heating and heat transfer in poly(dimethylsiloxane) microfluidic systems

New advances in microchip fabrication for electrochromatography

Direct detection of antibody–antigen binding using an on-chip artificial pore

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