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Opto-Electric Cellular Biosensor Using Optically Transparent Indium Tin Oxide (ITO) Electrodes

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ABSTRACT

Indium tin oxide (ITO) biosensors are used to perform simultaneous optical and electrical measurements in order to examine the dynamic cellular attachment, spreading, and proliferation of endothelial cells (ECs) as well as cytotoxic effects when exposed to cytochalasin D. A detailed description of the fabrication of these sensors is provided and their superior optical characteristics are qualitatively shown using four different microscopic images. Differential interference contrast microscopy (DICM) images were acquired simultaneously with micro-impedance measurements as a function of frequency and time. A digital image processing algorithm quantified the cell-covered electrode area as a function of time. In addition, cytotoxicity effects, produced by the toxic agent cytochalasin D, were examined using micro-impedance measurements, confocal microscopy images of stained actin-filaments, and interference reflection contrast microscopy (IRCM) capable of examining the bottom morphology of a cell. The results of this study show (1) the dynamic optical and electrical cellular characteristics using optically thin ITO biosensors; (2) qualitative agreement between cell-covered electrode area and electrical impedance during cellular attachment; (3) in vitro cytotoxicity detection of ECs due to 3 μM cytochalasin D. The present opto-electric biosensor system is unique in that a simultaneous and integrated cellular analysis is possible for a variety of living cells.

No MeSH data available.


Three methods to examine the cytotoxic effects of cytochalasin D on PPAECs. (a) Normalized resistance response. Data were obtained every 1.2 second, however in order to distinguish lines, only 20 data points were marked. Stained confocal images (b, c) of actin-filaments. Corresponding IRCM images of bottom morphology changes, 10 minutes before adding cytochalasin D (d), 240 minutes after adding cytochalasin D (e), and another 240 minutes after replacing the treated medium with new complete medium (f).
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f7-sensors-08-03257: Three methods to examine the cytotoxic effects of cytochalasin D on PPAECs. (a) Normalized resistance response. Data were obtained every 1.2 second, however in order to distinguish lines, only 20 data points were marked. Stained confocal images (b, c) of actin-filaments. Corresponding IRCM images of bottom morphology changes, 10 minutes before adding cytochalasin D (d), 240 minutes after adding cytochalasin D (e), and another 240 minutes after replacing the treated medium with new complete medium (f).

Mentions: Figure 7 presents three methods to examine the cytotoxic effects of cytochalasin D on endothelial cells. Fig. 7a shows the normalized resistance response of PPAECs on an ITO electrode when inoculated with 3 μM of Cytochalasin D. The resistance (black line) of naked scans, where no cells are present, remains constant while attached scans (blue line) under normal conditions show a constant decrease over time. However the addition of 3 μM of cytochalasin D shows an immediate decrease in the measured resistance. Note that there is no fluctuation in the naked scans and significantly less fluctuation after adding cytochalasin D, while attach scans under the normal cellular environmental conditions show relatively large fluctuations. There is also a distinctive peak due to the cellular attachment followed by decease in the normalized resistance in all the wells over the first several hours. Adding cytochalasin D produced a systematic decrease in the resistance and removal of the drug, achieved by replacing the medium, produced an abrupt increase.


Opto-Electric Cellular Biosensor Using Optically Transparent Indium Tin Oxide (ITO) Electrodes
Three methods to examine the cytotoxic effects of cytochalasin D on PPAECs. (a) Normalized resistance response. Data were obtained every 1.2 second, however in order to distinguish lines, only 20 data points were marked. Stained confocal images (b, c) of actin-filaments. Corresponding IRCM images of bottom morphology changes, 10 minutes before adding cytochalasin D (d), 240 minutes after adding cytochalasin D (e), and another 240 minutes after replacing the treated medium with new complete medium (f).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3675542&req=5

f7-sensors-08-03257: Three methods to examine the cytotoxic effects of cytochalasin D on PPAECs. (a) Normalized resistance response. Data were obtained every 1.2 second, however in order to distinguish lines, only 20 data points were marked. Stained confocal images (b, c) of actin-filaments. Corresponding IRCM images of bottom morphology changes, 10 minutes before adding cytochalasin D (d), 240 minutes after adding cytochalasin D (e), and another 240 minutes after replacing the treated medium with new complete medium (f).
Mentions: Figure 7 presents three methods to examine the cytotoxic effects of cytochalasin D on endothelial cells. Fig. 7a shows the normalized resistance response of PPAECs on an ITO electrode when inoculated with 3 μM of Cytochalasin D. The resistance (black line) of naked scans, where no cells are present, remains constant while attached scans (blue line) under normal conditions show a constant decrease over time. However the addition of 3 μM of cytochalasin D shows an immediate decrease in the measured resistance. Note that there is no fluctuation in the naked scans and significantly less fluctuation after adding cytochalasin D, while attach scans under the normal cellular environmental conditions show relatively large fluctuations. There is also a distinctive peak due to the cellular attachment followed by decease in the normalized resistance in all the wells over the first several hours. Adding cytochalasin D produced a systematic decrease in the resistance and removal of the drug, achieved by replacing the medium, produced an abrupt increase.

View Article: PubMed Central

ABSTRACT

Indium tin oxide (ITO) biosensors are used to perform simultaneous optical and electrical measurements in order to examine the dynamic cellular attachment, spreading, and proliferation of endothelial cells (ECs) as well as cytotoxic effects when exposed to cytochalasin D. A detailed description of the fabrication of these sensors is provided and their superior optical characteristics are qualitatively shown using four different microscopic images. Differential interference contrast microscopy (DICM) images were acquired simultaneously with micro-impedance measurements as a function of frequency and time. A digital image processing algorithm quantified the cell-covered electrode area as a function of time. In addition, cytotoxicity effects, produced by the toxic agent cytochalasin D, were examined using micro-impedance measurements, confocal microscopy images of stained actin-filaments, and interference reflection contrast microscopy (IRCM) capable of examining the bottom morphology of a cell. The results of this study show (1) the dynamic optical and electrical cellular characteristics using optically thin ITO biosensors; (2) qualitative agreement between cell-covered electrode area and electrical impedance during cellular attachment; (3) in vitro cytotoxicity detection of ECs due to 3 μM cytochalasin D. The present opto-electric biosensor system is unique in that a simultaneous and integrated cellular analysis is possible for a variety of living cells.

No MeSH data available.