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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.

Show MeSH
(a) Resistance distribution ΔRx/ΔR0 as the RBC passes between the electrodes; (b) the relationship between the half-bandwidth of ΔRx/ΔR0, δ, and the deformation index DI (simulation).
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f5-sensors-12-10566: (a) Resistance distribution ΔRx/ΔR0 as the RBC passes between the electrodes; (b) the relationship between the half-bandwidth of ΔRx/ΔR0, δ, and the deformation index DI (simulation).

Mentions: Figure 5(a) shows the relationship between the xRBC and ΔRx/ΔR0 that was observed in the cases of DI = 0 and 0.5. Here, ΔRx, which is defined as ΔRx = Rx − R∞, is normalized with ΔR0 (= R0 − R∞). In both DI cases, ΔRx/ΔR0 becomes a maximum at xRBC = 0. ΔRx/ΔR0, then, will decrease as /xRBC/ increases. Furthermore, comparing the cases of DI = 0 and 0.5, a broader distribution is observed in the case of DI = 0.5. This is attributed to fact that an ellipsoidal RBC possesses a larger streamwise length, a.


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) Resistance distribution ΔRx/ΔR0 as the RBC passes between the electrodes; (b) the relationship between the half-bandwidth of ΔRx/ΔR0, δ, and the deformation index DI (simulation).
© Copyright Policy
Related In: Results  -  Collection

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

f5-sensors-12-10566: (a) Resistance distribution ΔRx/ΔR0 as the RBC passes between the electrodes; (b) the relationship between the half-bandwidth of ΔRx/ΔR0, δ, and the deformation index DI (simulation).
Mentions: Figure 5(a) shows the relationship between the xRBC and ΔRx/ΔR0 that was observed in the cases of DI = 0 and 0.5. Here, ΔRx, which is defined as ΔRx = Rx − R∞, is normalized with ΔR0 (= R0 − R∞). In both DI cases, ΔRx/ΔR0 becomes a maximum at xRBC = 0. ΔRx/ΔR0, then, will decrease as /xRBC/ increases. Furthermore, comparing the cases of DI = 0 and 0.5, a broader distribution is observed in the case of DI = 0.5. This is attributed to fact that an ellipsoidal RBC possesses a larger streamwise length, a.

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