A differential viscosity detector for use in miniaturized chemical separation systems

Blom, M.T.; Chmela, E.; Heyden, Frank H. J. van der; Oosterbroek, R.E.; Tijssen, R.; Elwenspoek, M.; Berg, Albert van den

doi:10.1109/jmems.2004.840452

Cited by 18 publications

(10 citation statements)

References 38 publications

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“…7). A least-squares fit, using [ , 3 ] as the basis functions, is performed for each set of points (corresponding to different temperatures). This gives us the linear and cubic stiffnesses at different temperatures.…”

Section: Mechanical Parameters and Functionsmentioning

confidence: 99%

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Thermomechanical transitions in doubly-clamped micro-oscillators

Sahai

Bhiladvala

Zehnder

2007

International Journal of Non-Linear Mechanics

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Section: Mechanical Parameters and Functionsmentioning

confidence: 99%

“…Ilic et al [2] used MEMS oscillators as sensors for the detection of E. coli. Blom et al [3] successfully used MEMS oscillators to measure fluid density and viscosity. MEMS oscillators have also been used as reference oscillators [4] and to demonstrate signal processing [5] functions.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical transitions in doubly-clamped micro-oscillators

Sahai

Bhiladvala

Zehnder

2007

International Journal of Non-Linear Mechanics

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“…In order to overcome these technical limitations of conventional viscometers, several microfluidic devices have been proposed. [10][11][12][13] Nevertheless, these microfluidic platforms also require calibration procedures using a standard fluid as a reference. Moreover, additional procedures with intricate mathematical models are required to measure the viscosity of non-Newtonian fluids.…”

Section: Introductionmentioning

confidence: 99%

Changes in velocity profile according to blood viscosity in a microchannel

2014

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Red blood cells (RBCs) are important to dictate hemorheological properties of blood. The shear-thinning effect of blood is mainly attributed to the characteristics of the RBCs. Variations in hemorheological properties alter flow resistance and wall shear stress in blood vessels. Therefore, detailed understanding of the relationship between the hemorheological and hemodynamic properties is of great importance. In this study, blood viscosity and blood flow were simultaneously measured in the same microfluidic device by monitoring the flow-switching phenomenon. To investigate blood flows according to hemorheological variations, the flow rate of blood samples (RBCs suspended in autologous plasma, dextrantreated plasma, and in phosphate buffered saline solution) was precisely controlled with a syringe pump. Velocity profiles of blood flows were measured by using a micro-particle image velocimetry technique. The shape of velocity profiles was quantified by using a curve-fitting equation. It is found that the shape of the velocity profiles is highly correlated with blood viscosity. To demonstrate the relationship under ex vivo conditions, biophysical properties and velocity profiles were measured in an extracorporeal rat bypass loop. Experimental results show that increased blood viscosity seems to induce blunt velocity profile with high velocity component at the wall of the microchannel. Simultaneous measurement of blood viscosity and velocity profile would be useful for understanding the effects of hemorheological features on the hemodynamic characteristics in capillary blood vessels. V C 2014 AIP Publishing LLC. [http://dx

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“…The problem is a subtle mix of pragmatism and technological limits. In addition to issues of dead volumes in standard pressure-measurement techniques (16)(17)(18) and those associated with interfacing microelectromechanical system devices to standard pressure gauges (19), existing techniques are simply difficult to implement [lasers, quadrant diodes, deformable membranes, multistep process of production (16)(17)(18)] and are unable to measure at millisecond rates the pressure changes in micrometer-scale flows. For instance, when a single red blood cell (RBC) enters a channel of 5 ϫ 5 m, the volume variation produced by a flow at physiological speeds of a few millimeters per second is Ϸ100 fL in a few milliseconds, which represents a typical pressure-drop variation of tens to hundreds of pascals.…”

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confidence: 99%

High-speed microfluidic differential manometer for cellular-scale hydrodynamics

Abkarian

Faivre

Stone

2006

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

168

133

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We propose a broadly applicable high-speed microfluidic approach for measuring dynamical pressure-drop variations along a micrometer-sized channel and illustrate the potential of the technique by presenting measurements of the additional pressure drop produced at the scale of individual flowing cells. The influence of drug-modified mechanical properties of the cell membrane is shown. Finally, single hemolysis events during flow are recorded simultaneously with the critical pressure drop for the rupture of the membrane. This scale-independent measurement approach can be applied to any dynamical process or event that changes the hydrodynamic resistance of micro-or nanochannels.pressure measurement ͉ microcirculation ͉ hemolysis ͉ red blood cell ͉ membrane properties F luid motions at the micrometer scale are at the heart of many recent developments in microfabrication (1), separation processes (2), cellular-scale identifications (3), DNA sequencing (4), protein crystallization (5) and many basic transport pathways in plants (6), in the microcirculation (7), and specific to industrial processes. The main characteristics of these advances lie in the manipulation and understanding of the dynamics of ''soft'' objects such as polymers (8) (e.g., DNA), drops (9, 10), microemulsions (11), microfoams (12), cells (13), vesicles and microcapsules (14). In fact, the interaction of the flow with these deformable entities is a tool to further investigate the details of their mechanical properties and their structural features (e.g., the entropic elasticity of a polymer, the viscoelastic properties of a capsule, or the rheology of the liquid film between microbubbles in a foam). For the case of strong confinement offered by microchannels, the flow and shape of any close-fitting soft object is controlled by a competition among the properties of the objects, the fluid pressure, and the viscous stresses acting on the boundaries that resist the motion. The hydrodynamic resistance resulting from this fluid-structure interaction is reflected in a dynamical variation of the pressure drop along the channel during the flow and hence represents a crucial parameter to be measured.Nevertheless, rapid variations of pressure are very difficult to measure at the micrometer scale and below. Indeed, the difficulties do not originate from the lack of precision sensors commercially available or those described in the research literature (15). The problem is a subtle mix of pragmatism and technological limits. In addition to issues of dead volumes in standard pressure-measurement techniques (16-18) and those associated with interfacing microelectromechanical system devices to standard pressure gauges (19), existing techniques are simply difficult to implement [lasers, quadrant diodes, deformable membranes, multistep process of production (16-18)] and are unable to measure at millisecond rates the pressure changes in micrometer-scale flows. For instance, when a single red blood cell (RBC) enters a channel of 5 ϫ 5 m, the volume variation produced b...

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A differential viscosity detector for use in miniaturized chemical separation systems

Cited by 18 publications

References 38 publications

Thermomechanical transitions in doubly-clamped micro-oscillators

Thermomechanical transitions in doubly-clamped micro-oscillators

Changes in velocity profile according to blood viscosity in a microchannel

High-speed microfluidic differential manometer for cellular-scale hydrodynamics

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