Microfluidic ion-sensing devices

Johnson, R. Daniel; Gavalas, Vasilis G.; Daunert, Sylvia; Bachas, Leonidas G.

doi:10.1016/j.aca.2008.02.041

Cited by 33 publications

(25 citation statements)

References 88 publications

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“…This propulsion mode possesses advantages that make it an oft-favored alternative to electrokinetic, hydrodynamic pressure-driven, and electrowetting-based devices (Mark et al 2010), including: insensitivity of propulsion to fluid properties such as pH and ionic strength, compatibility with a variety of platform materials, and the use of a simple, inexpensive motor to achieve propulsion Ducrée et al 2007). As a result, a range of applications, including chemical separations, biological assays, polymerase chain reaction, ion/electrolyte analysis, etc., have been demonstrated in a centrifugal microfluidic format (Gorkin et al 2010;Moschou et al 2006;Sundberg et al 2010;Lee et al 2009;Johnson et al 2001;Johnson et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing

Moore

McCuiston

Mittendorf

et al. 2010

Microfluid Nanofluid

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This paper details the behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional (3D), or solid-object, printing. Microfluidic structures containing valve channels with different widths, heights, and radial distances from the center of rotation were studied and compared with extant capillary valve theories. Due to the printing process, the produced valve channels possessed a ridged or ''scalloped'' pattern. Hence, actual channel widths at the widest and narrowest points of the ridged pattern were determined, and used in comparisons between theoretical and empirical values. In addition, variations in contact angle resulting from the ridged pattern were measured and employed in theoretical calculations. For 1-mm high valve channels, the critical angular frequency (rpm) required to overcome capillary valve pressure was found to be independent of width. However, as the height of the valve channel was reduced, the critical rpm was found to become progressively more width-dependent increasing more rapidly for narrower channels. Both of these observations point to a role for feature sharpness, as well as the geometry of the valve channel opening, in valve behavior. Otherwise, valves followed a predictable trend of increasing critical rpm with decreased valve height and decreased radial distance from the rotation center. Using these results as a guide, then, it is possible to prepare centrifugal microfluidic devices by 3D printing with operability comparable to devices prepared by other microfabrication techniques.

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Section: Introductionmentioning

confidence: 99%

Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing

Moore

McCuiston

Mittendorf

et al. 2010

Microfluid Nanofluid

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“…The reason is that the concentration gradient exists only near the surface of the electrode; this is very useful for microfluidic chip measurements, where no stirring is possible. A novel approach here is to utilize a self-assembly Polystyrene (PS) nanobeads with hydrophobic surfaces to build the liquid ion exchange column [20] connected to a hydrophilic silica nanobeads-packed column, which is considered as one of the most difficult tasks in the development of ion-selective microelectrodes [21]. PS nanoparticles have become widely used materials since the particles are commercially available in a wide range of sizes with narrow size distribution [22].…”

Section: Resultsmentioning

confidence: 99%

Potentiometric and voltammetric polymer lab chip sensors for determination of nitrate, pH and Cd(II) in water

Jang

Zou

Lee

et al. 2010

Talanta

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Due to their toxicity to humans and animals, heavy metals and nitrate in groundwater are of particular concern. The combination of high toxicity and widespread occurrence has created a pressing need for effective monitoring and measurement of nitrate and heavy metals in soil pore water and groundwater at shallow depths. In this work, a new electrochemical sensing platform with the self-assembly nanobeads packed (nBP) hetero columns has been developed for the pH and nitrate measurements. In addition, for on-site determination of cadmium (Cd(II)), a bismuth (Bi(III)) based polymer lab chip sensor using the square-wave anodic stripping voltammetry (SWASV) sensing principle has been designed, fabricated and successfully characterized. Factors affecting sensitivity and precision of the sensor, including deposition potential and deposition time, were studied. Miniaturized electrochemical lab chip sensors could be very valuable in environmental monitoring area due to their many benefits, such as greatly reduced sensing cost, sensing system portability, and ease of use.

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“…Studies of ion perturbations in small, individual cells predominantly rely on the use of ion-sensitive dyes. In order to overcome size limitation, exciting efforts are currently underway to create miniaturized ISMs, and arrays of ISMs, by harnessing microfluidics technology (reviewed in reference [58]). Furthermore, ion-selective cocktails with novel and improved characteristics and ion-selectivities are constantly in development (e.g., [59–61] and review of ion-selective electrodes based on PVC-membranes that could be incorporated into ISMs in reference [62]), broadening the range of studies to which ISMs can be applied.…”

Section: Discussionmentioning

confidence: 99%

Monitoring Ion Activities In and Around Cells Using Ion-Selective Liquid-Membrane Microelectrodes

Lee

Boron

Parker

2013

Sensors

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Determining the effective concentration (i.e., activity) of ions in and around living cells is important to our understanding of the contribution of those ions to cellular function. Moreover, monitoring changes in ion activities in and around cells is informative about the actions of the transporters and/or channels operating in the cell membrane. The activity of an ion can be measured using a glass microelectrode that includes in its tip a liquid-membrane doped with an ion-selective ionophore. Because these electrodes can be fabricated with tip diameters that are less than 1 μm, they can be used to impale single cells in order to monitor the activities of intracellular ions. This review summarizes the history, theory, and practice of ion-selective microelectrode use and brings together a number of classic and recent examples of their usefulness in the realm of physiological study.

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Microfluidic ion-sensing devices

Cited by 33 publications

References 88 publications

Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing

Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing

Potentiometric and voltammetric polymer lab chip sensors for determination of nitrate, pH and Cd(II) in water

Monitoring Ion Activities In and Around Cells Using Ion-Selective Liquid-Membrane Microelectrodes

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