Experimental Studies of Electroosmotic Flow Dynamics in Microfabricated Devices during Current Monitoring Experiments

Pittman, Jason L.; Henry, Charles S.; Gilman, S. Douglass

doi:10.1021/ac026132n

Cited by 81 publications

(72 citation statements)

References 51 publications

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“…Although photobleaching has been applied to measure flow velocity with different mechanisms [39][40][41][42][43][44] as mentioned in the introduction, LIFPA seems to be a novel method and shows several advantages. For instance, the two points based method in Pittman et al 44 can only measure the bulk flow velocity and the temporal resolution is limited, since it has to wait for the bleached dye slug to translate from the laser beam to the detecting point.…”

Section: Discussionmentioning

confidence: 99%

Laser induced fluorescence photobleaching anemometer for microfluidic devices

Wang

2005

Lab Chip

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We have developed a novel, non-intrusive fluid velocity measurement method based on photobleaching of a fluorescent dye for microfluidic devices. The residence time of the fluorescent dye in a laser beam depends on the flow velocity and approximately corresponds to the decaying time of the photobleaching of the dye in the laser beam. The residence time is inversely proportional to the flow velocity. The fluorescence intensity increases with the flow velocity due to the decrease of the residence time. A calibration curve between fluorescence intensity and known flow velocity should be obtained first. The calibration relationship is then used to calculate the flow velocity directly from the measured fluorescence intensity signal. The new method can measure the velocity very quickly and is easy to use. It is demonstrated for both pressure driven flow and electroosmotic flow.

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Section: Discussionmentioning

confidence: 99%

Laser induced fluorescence photobleaching anemometer for microfluidic devices

Wang

2005

Lab Chip

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“…13,[17][18][19] All channels were first filled with a 50 mM phosphate buffer, and a 25 mM phosphate buffer was injected into the cathodic buffer port. Then, a potential of 1.00 kV (167 V/cm) was applied by a high-voltage sequencer (HVS448-6000D-ST, LabSmith, CA) across the whole straight channel, and the current through the channel was monitored.…”

Section: Mce Experimentsmentioning

confidence: 99%

Simple and Rapid Immobilization of Coating Polymers on Poly(dimethyl siloxane)-glass Hybrid Microchips by a Vacuum-drying Method

et al. 2015

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A simple and rapid vacuum-drying modification method was applied to several neutral and charged polymers to obtain coating layers for controlling electroosmotic flow (EOF) and suppressing sample adsorption on poly(dimethyl siloxane) (PDMS)-glass hybrid microchips. In the vacuum-dried poly(vinylpyrrolidone) coating, the electroosmotic mobility (μeo) was suppressed from +2.1 to +0.88 × 10 -4 cm 2 /V·s, and the relative standard deviation (RSD) of μeo was improved from 10.2 to 2.5% relative to the bare microchannel. Among several neutral polymers, poly(vinylalcohol) (PVA) and poly(dimethylacrylamide) coatings gave more suppressed and repeatable EOF with RSDs of less than 2.3%. The vacuum-drying method was also applicable to polyanions and polycations to provide accelerated and inversed EOF, respectively, with acceptable RSDs of less than 4.9%. In the microchip electrophoresis (MCE) analysis of bovine serum albumin (BSA) in the vacuum-dried and thermally-treated PVA coating channel, an almost symmetric peak of BSA was obtained, while in the native microchannel a significantly skewed peak was observed. The results demonstrated that the vacuum-dried polymer coatings were effective to control the EOF, and reduced the surface adsorption of proteins in MCE.

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“…Photobleached-fluorescence imaging (where the fluorescence of a dilute and neutral fluorophore is suppressed by exposing it to visible excitation light) has also been developed for monitoring EOF [32][33][34][35], but this technique has not yet been applied to characterize surface modifications, although it offers the advantage of using a very low concentration of marker, and will work with both glass and polymer microchannels, which are transparent to visible light.…”

Section: Spatially Resolved Eof Measurementsmentioning

confidence: 99%

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

et al. 2006

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The control and modification of surface state is a major challenge in bioanalytical sciences, and in particular in electrokinetic separation methods, due to the importance of electroosmosis. This topic has gained recently a renewed interest, associated with the development of "lab-on-chips" systems that extend the range of materials in which separation channels are fabricated. The surface science community has developed through the years a large toolbox of characterization tools and surface modification protocols, which is not yet fully exploited in the bioanalytical world. In this paper, we try and present an overview of these tools, in order to stimulate new ideas for improved and more controlled surface treatment strategies for separations in capillaries and microchannels. We briefly describe some physical and chemical aspects of electroosmosis (global and spatially resolved), streaming current, and streaming potential. We also review the main strategies for surface coating, and compare the advantages of physisorption, well-organized thin self-assembled monolayers, or conversely thick polymer "brushes". Examples of existing applications to electrophoresis in microchannel are also given.

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Experimental Studies of Electroosmotic Flow Dynamics in Microfabricated Devices during Current Monitoring Experiments

Cited by 81 publications

References 51 publications

Laser induced fluorescence photobleaching anemometer for microfluidic devices

Laser induced fluorescence photobleaching anemometer for microfluidic devices

Simple and Rapid Immobilization of Coating Polymers on Poly(dimethyl siloxane)-glass Hybrid Microchips by a Vacuum-drying Method

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

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