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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) Relationship between the normalized resistance distribution ΔRx/ΔR0 against the streamwise position of RBC, xRBC, for normal RBC, rigidified RBC and spherocyte; (b) photographs of normal and rigidified RBCs passing between the electrodes.
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f6-sensors-12-10566: (a) Relationship between the normalized resistance distribution ΔRx/ΔR0 against the streamwise position of RBC, xRBC, for normal RBC, rigidified RBC and spherocyte; (b) photographs of normal and rigidified RBCs passing between the electrodes.

Mentions: Figure 6(a) shows the distribution of the resistance ratio ΔRx/ΔR0 at the moment when the RBC passed between the electrodes. The abscissa xRBC is the streamwise position of the RBC. xRBC was obtained by multiplying the time recorded by the electrical measurement by the streamwise velocity of the RBC as measured by the high-speed camera. ΔRx, ΔR0, and ΔR∞ are defined in the same way as in Section 4.1. The results that represent the distributions of the normal RBC, rigidified RBC, and spherocytes are shown in the figure. In addition to this, photographs of a normal RBC and rigidified one passing between the electrodes are shown in Figure 6(b). This result corresponds exactly with that of a RBC shown in the ΔRx/ΔR0 graph. One can see in the photographs that the RBC is stretched in a streamwise direction by the shear flow and maintains its ellipsoidal shape while passing 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) Relationship between the normalized resistance distribution ΔRx/ΔR0 against the streamwise position of RBC, xRBC, for normal RBC, rigidified RBC and spherocyte; (b) photographs of normal and rigidified RBCs passing between the electrodes.
© Copyright Policy
Related In: Results  -  Collection

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

f6-sensors-12-10566: (a) Relationship between the normalized resistance distribution ΔRx/ΔR0 against the streamwise position of RBC, xRBC, for normal RBC, rigidified RBC and spherocyte; (b) photographs of normal and rigidified RBCs passing between the electrodes.
Mentions: Figure 6(a) shows the distribution of the resistance ratio ΔRx/ΔR0 at the moment when the RBC passed between the electrodes. The abscissa xRBC is the streamwise position of the RBC. xRBC was obtained by multiplying the time recorded by the electrical measurement by the streamwise velocity of the RBC as measured by the high-speed camera. ΔRx, ΔR0, and ΔR∞ are defined in the same way as in Section 4.1. The results that represent the distributions of the normal RBC, rigidified RBC, and spherocytes are shown in the figure. In addition to this, photographs of a normal RBC and rigidified one passing between the electrodes are shown in Figure 6(b). This result corresponds exactly with that of a RBC shown in the ΔRx/ΔR0 graph. One can see in the photographs that the RBC is stretched in a streamwise direction by the shear flow and maintains its ellipsoidal shape while passing 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