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Microfluidics
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Microfluidic devices are characterized by channels with
diameters ranging roughly
between 100 nm and 100 microns, often involving particles
with diameters ranging
roughly from 10 nm to 10 microns. At these length scales,
the Reynolds number
is low and the flow is usually laminar. Because the diameters are
small and it is
difficult to generate large flow velocities with pressure,
other effects can
dominate. In particular, electrokinetic effects
(electroosmosis and
electrophoresis) can dominate and voltage can be
used to manipulate fluids,
molecules, and particles. Surface tension can also
be very important, and
bubbles and drops can often be manipulated with
temperature and electric fields.
We are focused on several aspects of microfluidics: (1)
using microscale devices to control flow patterns for
fiber processing,
materials synthesis,
and
pharmaceutical production;
(2) using microscale devices
as a platform to understand
electrokinetic phenomena at interfaces;
and (3)
using microfabricated
structures to
sort
and
study
cells.
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Selected Publications and Presentations on Microfluidic Transport
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Hawkins BG,
Gleghorn JP,
Kirby BJ
"Dielectrophoresis for cell and particle manipulation,"
submitted, 2008.
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Kondapalli S,
Kirby BJ
"Refolding of beta-galactosidase: Microfluidic device for reagent metering
and mixing and quantification of refolding yield,"
submitted, 2008.
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Kondapalli S,
Kirby BJ
"Microfluidic devices for protein refolding," CHI PepTalk 2008, San Diego, CA, Jan 2008.
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George PA, Hui W, Rana F,
Hawkins BG,
Smith AE,
Kirby BJ
"Integrated microfluidic devices for terahertz spectroscopy of biomolecules",
Optics Express, 16(3) 1577-1582 (2008).
pdf
text
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Kondapalli S,
Putnam DA,
Kirby BJ
"Protein refolding in microchips",
AIChE 2007, Salt Lake City, UT, November 2007.
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Rouillard AD,
Tsui Y,
Polacheck WJ,
Lee JY,
Bonassar LJ,
Kirby BJ
"Micropatterned hydrogel tissue scaffolds with controlled
electrokinetic properties for investigation of chondrocyte
mechanotransduction", MicroTAS 2007, Paris, France, October 2007.
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Tandon V,
Bhagavatula SK,
Nelson WC,
Kirby BJ
"Zeta potential and electroosmotic mobility in microfluidic devices
fabricated from hydrophobic polymers: 1. The origins of charge",
Electrophoresis 29(5):1092-1101, 2008.
doi
pdf
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Tandon V,
Kirby BJ
"Zeta potential and electroosmotic mobility in microfluidic devices
fabricated from hydrophobic polymers: 2. Slip and interfacial water structure",
Electrophoresis 29(5):1102-1114, 2008.
doi
pdf
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Rouillard AD,
Tsui Y,
Polacheck WJ,
Lee JY,
Bonassar LJ,
Kirby BJ
"Control of the electromechanical proterties of alginate
tissue scaffolds via ionic and covalent crosslinking
and microparticle doping", BMES 2007, Los Angeles, CA, September 2007.
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Hawkins BG,
Smith AE,
Syed YA,
Kirby BJ
"Continuous-flow particle separation by 3D insulative
dielectrophoresis using coherently shaped, DC-biased,
AC electric fields,"
Analytical Chemistry, 2007.
doi
pdf
text
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Hawkins BG,
Smith AE, Syed YA,
Kirby BJ
"Continuous-flow dielectrophoretic particle separation in polymeric
microchannels,"
3rd New York Complex Matter Workshop Syracuse, NY, Dec 2006.
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Reissman TR, Fang A, Garcia ER,
Kirby BJ,
Viard R, Fauchet P
"Inorganic proton exchange membranes," FuelCell 2006, Irvine, CA.
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Mela P, van den Berg A, Fintschenko Y,
Cummings EB, Simmons BA,
Kirby BJ
"The zeta potential of cyclo-olefin polymer microchannels and its effects on insulative (electrodeless)
dielectrophoresis particle trapping devices,"
Electrophoresis 26:1792-1799 (2005).
doi
pdf
text
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Reichmuth DS, Shepodd TJ,
Kirby BJ
"Microchip HPLC of peptides and proteins,"
Analytical Chemistry 77:2997-3000 (2005).
doi
pdf
text
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Kirby BJ,
Reichmuth DS, Renzi RF, Shepodd TJ,
Wiedenman BJ
"Microfluidic routing of aqueous and
organic flows at high pressure: Fabrication and
characterization of integrated polymer microvalve elements,"
Lab on a Chip 5:184-190 (2005).
doi
pdf
text
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Song S, Mela P, van den Berg A,
Kirby BJ
"Microfluidic architectures for integrated cell lysis,
lysate dialysis and cell stimulus," in MicroTAS 2004, Kluwer Academic Publishers (2004).
pdf
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Reichmuth DS, Shepodd TJ,
Kirby BJ
"On-chip
high-pressure picoliter injector for pressure-driven flow
through porous media," Analytical Chemistry
76:5063-5068 (2004).
doi
pdf
text
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Song S, Singh AK,
Kirby BJ
"Electrophoretic
Concentration of Proteins at Laser-Patterned Porous
Membranes," Analytical Chemistry 76:4589-4592 (2004).
doi
pdf
text |
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Song S, Singh AK, Shepodd TJ,
Kirby BJ
"Microchip dialysis of proteins using in situ
photopatterned nanoporous polymer membranes", Analytical
Chemistry 76:2367-2373 (2004).
doi
pdf
text
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Kirby BJ,
Hasselbrink, Jr. EF
"The Zeta
Potential of Microfluidic Substrates. 1. Theory, experimental
techniques, and effects on separations,"
Electrophoresis, 25:187-202
(2004).
doi
pdf
text
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Kirby BJ,
Hasselbrink, Jr. EF
"The Zeta
Potential of Microfluidic Substrates. 2. Data for polymers,"
Electrophoresis, 25:203-213 (2004).
doi
pdf
text
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Reichmuth DS, Shepodd TJ,
Kirby BJ
"RP-HPLC microchip
separations with subnanoliter on-chip pressure injections," in MicroTAS 2003, Kluwer Academic Publishers (2003).
pdf
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Reichmuth DS,
Kirby BJ
"Effects of
Ammonioalkyl sulfonate internal salts on electrokinetic
micropump performance and Reversed-Phase HPLC separations,"
Journal of Chromatography A, 1013:93-101
(2003).
doi
pdf
text
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Reichmuth DS, Chirica GS,
Kirby BJ
"Increasing the Performance of High-Pressure,
High-Efficiency Electrokinetic Micropumps Using Zwitterionic
Solute Additives," Sensors and Actuators B-Chemical, 92:37-43 (2003).
doi
pdf
text
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Fintschenko Y,
Kirby BJ,
Hasselbrink, Jr. EF,
Singh AK, Shepodd TJ
"Monolithic Materials: Miniature
and Microchip Technologies," in Monolithic Materials:
Preparation, Properties, and Applications Elsevier,
Amsterdam (2003).
pdf
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Kirby BJ,
Wheeler AR, Zare RN, Fruetel JA,
Shepodd TJ
"Programmable Modification of Cell Adhesion
and Zeta Potential in Silica Microchips,"Lab On a Chip
3:5-10 (2003).
doi
pdf
text
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Kirby BJ,
Shepodd TJ, Hasselbrink, Jr. EF
"Voltage-Addressable On/Off Microvalves for High-Pressure
Microchip Separations," Journal of Chromatography A
979:147-154 (2002).
doi
pdf
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Counterflow mass exchange microchip demonstrating desalting of a protein sample. Fluorescently-labeled
protein (yellow; lactalbumin) mixed with low-molecular-weight dye is injected at top right
and exits at top left. A counterflow of water
is injected at lower left and exits at lower right. The dye (red; used as a visible marker to represent salt)
is extracted, as can be seen by the red signal that grows from left to right. The image is a composite of
several images; this membrane has an actual aspect ratio of approximately 200:1.
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Cartoon of high-pressure injector operation (place mouse on image to animate).
Flow of mobile phase from left is forced through the separation column at top.
Pressure pulses at right cause a fluoropolymer switch(blue) to move to left, closing
the mobile phase line off from the system and connecting the sample fluid (green) to
the separation column. After a small volume of sample (~200 pL) is injected, the
fluoropolymer switch returns to its original position, and a chromatographic separation
is performed at high pressure. This
high-pressure microfluidic control element
is created using
laser-polymerization.
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