A Microfluidic Diluter Based on Pulse Width Flow Modulation

We demonstrate that pulse width flow modulation (PWFM) can be used to design fast, accurate, and precise multistage dilution modules for microfluidic devices. The PWFM stage unit presented here yields 10-fold dilution, but several PWFM stages can be connected in series to yield higher-order dilution...

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Bibliographic Details
Published inAnalytical chemistry (Washington) Vol. 81; no. 13; pp. 5549 - 5556
Main Authors Ainla, Alar, Gözen, Irep, Orwar, Owe, Jesorka, Aldo
Format Journal Article
LanguageEnglish
Published Washington, DC American Chemical Society 01.07.2009
Subjects
Analytical chemistry
bilayers
biosensors
Calcium - chemistry
Chemical compounds
Chemistry
device
dynamic chemical signals
Exact sciences and technology
Fluids
Fluorescent Dyes - chemistry
generation
Hydraulics
hydrophilic surfaces
Indicator Dilution Techniques - instrumentation
Lipid Bilayers - metabolism
liposomes
Membranes
Microfluidics - instrumentation
Microfluidics - methods
nanoliter-scale
networks
Silicon Dioxide - chemistry
Fluid mechanics
Dilution
Phospholipid
Membrane
Bilayer
Pulse modulation
Microfluidics
Mold
Variance
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Summary:We demonstrate that pulse width flow modulation (PWFM) can be used to design fast, accurate, and precise multistage dilution modules for microfluidic devices. The PWFM stage unit presented here yields 10-fold dilution, but several PWFM stages can be connected in series to yield higher-order dilutions. We have combined two stages in a device thus capable of diluting up to 100-fold, and we have experimentally determined a set of rules that can be conveniently utilized to design multistage diluters. Microfabrication with resist-based molds yielded geometrical channel height variances of 7% (22.9(16) μm) with corresponding hydraulic resistance variances of ∼20%. Pulsing frequencies, channel lengths, and flow pressures can be chosen within a wide range to establish the desired diluter properties. Finally, we illustrate the benefits of on-chip dilution in an example application where we investigate the effect of the Ca2+ concentration on a phospholipid bilayer spreading from a membrane reservoir onto a SiO2 surface. This is one of many possible applications where flexible concentration control is desirable.
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ISSN:0003-2700
1520-6882
1520-6882
DOI:10.1021/ac9010028