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Numerical and experimental study on the development of electric sensor as for measurement of red blood cell deformability in microchannels.

Tatsumi K, Katsumoto Y, Fujiwara R, Nakabe K - Sensors (Basel) (2012)

Bottom Line: Then, a microsensor was designed and fabricated on the basis of the numerical results.Resistance measurement was carried out using samples of normal RBCs and rigidified (Ca(2+)-A23186 treated) RBCs.Visualization measurement of the cells' behavior was carried out using a high-speed camera, and the results were compared with those obtained above to evaluate the performance of the sensor.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering and Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan. tatsumi@me.kyoto-u.ac.jp

ABSTRACT
A microsensor that can continuously measure the deformability of a single red blood cell (RBC) in its microchannels using microelectrodes is described in this paper. The time series of the electric resistance is measured using an AC current vs. voltage method as the RBC passes between counter-electrode-type micro-membrane sensors attached to the bottom wall of the microchannel. The RBC is deformed by the shear flow created in the microchannel; the degree of deformation depends on the elastic modulus of the RBC. The resistance distribution, which is unique to the shape of the RBC, is analyzed to obtain the deformability of each cell. First, a numerical simulation of the electric field around the electrodes and RBC is carried out to evaluate the influences of the RBC height position, channel height, distance between the electrodes, electrode width, and RBC shape on the sensor sensitivity. Then, a microsensor was designed and fabricated on the basis of the numerical results. Resistance measurement was carried out using samples of normal RBCs and rigidified (Ca(2+)-A23186 treated) RBCs. Visualization measurement of the cells' behavior was carried out using a high-speed camera, and the results were compared with those obtained above to evaluate the performance of the sensor.

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(a) and (b) schematics of the microchannel and electrodes of the sensor used in the experiment; (c) photograph of the electrodes used in the experiment; (d) schematic of the sensor electric circuit.
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f3-sensors-12-10566: (a) and (b) schematics of the microchannel and electrodes of the sensor used in the experiment; (c) photograph of the electrodes used in the experiment; (d) schematic of the sensor electric circuit.

Mentions: Figure 3(a,b) shows a schematic diagram of the channel used in the experiment. The channel width, W, is 1 mm, which is much larger than the channel heights H1 and H2. The RBC, therefore, can be considered to deform on experiencing the shear stress from a two-dimensional channel flow. Three inlets were located upstream of the channel. RBCs suspended in solution were supplied from the central inlet, while the solution alone was supplied from the other two side flows. A sheath flow was thus generated in the channel that could guide the RBCs to the region between the electrodes.


Numerical and experimental study on the development of electric sensor as for measurement of red blood cell deformability in microchannels.

Tatsumi K, Katsumoto Y, Fujiwara R, Nakabe K - Sensors (Basel) (2012)

(a) and (b) schematics of the microchannel and electrodes of the sensor used in the experiment; (c) photograph of the electrodes used in the experiment; (d) schematic of the sensor electric circuit.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472844&req=5

f3-sensors-12-10566: (a) and (b) schematics of the microchannel and electrodes of the sensor used in the experiment; (c) photograph of the electrodes used in the experiment; (d) schematic of the sensor electric circuit.
Mentions: Figure 3(a,b) shows a schematic diagram of the channel used in the experiment. The channel width, W, is 1 mm, which is much larger than the channel heights H1 and H2. The RBC, therefore, can be considered to deform on experiencing the shear stress from a two-dimensional channel flow. Three inlets were located upstream of the channel. RBCs suspended in solution were supplied from the central inlet, while the solution alone was supplied from the other two side flows. A sheath flow was thus generated in the channel that could guide the RBCs to the region between the electrodes.

Bottom Line: Then, a microsensor was designed and fabricated on the basis of the numerical results.Resistance measurement was carried out using samples of normal RBCs and rigidified (Ca(2+)-A23186 treated) RBCs.Visualization measurement of the cells' behavior was carried out using a high-speed camera, and the results were compared with those obtained above to evaluate the performance of the sensor.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering and Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan. tatsumi@me.kyoto-u.ac.jp

ABSTRACT
A microsensor that can continuously measure the deformability of a single red blood cell (RBC) in its microchannels using microelectrodes is described in this paper. The time series of the electric resistance is measured using an AC current vs. voltage method as the RBC passes between counter-electrode-type micro-membrane sensors attached to the bottom wall of the microchannel. The RBC is deformed by the shear flow created in the microchannel; the degree of deformation depends on the elastic modulus of the RBC. The resistance distribution, which is unique to the shape of the RBC, is analyzed to obtain the deformability of each cell. First, a numerical simulation of the electric field around the electrodes and RBC is carried out to evaluate the influences of the RBC height position, channel height, distance between the electrodes, electrode width, and RBC shape on the sensor sensitivity. Then, a microsensor was designed and fabricated on the basis of the numerical results. Resistance measurement was carried out using samples of normal RBCs and rigidified (Ca(2+)-A23186 treated) RBCs. Visualization measurement of the cells' behavior was carried out using a high-speed camera, and the results were compared with those obtained above to evaluate the performance of the sensor.

Show MeSH