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Using white noise to gate organic transistors for dynamic monitoring of cultured cell layers.

Rivnay J, Leleux P, Hama A, Ramuz M, Huerta M, Malliaras GG, Owens RM - Sci Rep (2015)

Bottom Line: These properties are critical for electrical detection of tissue health and viability in applications such as toxicological screening.By applying uniform white noise at the gate of an organic electrochemical transistor (OECT), and measuring the resulting current noise, we are able to dynamically monitor the impedance and thus integrity of cultured epithelial monolayers.We show that noise sourcing can be used to track rapid monolayer disruption due to compounds which interfere with dynamic polymerization events crucial for maintaining cytoskeletal integrity, and to resolve sub-second alterations to the monolayer integrity.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioelectronics, Ecole Nationale Superieure des Mines, CMP-EMSE, MOC, 13541 Gardanne, France.

ABSTRACT
Impedance sensing of biological systems allows for monitoring of cell and tissue properties, including cell-substrate attachment, layer confluence, and the "tightness" of an epithelial tissue. These properties are critical for electrical detection of tissue health and viability in applications such as toxicological screening. Organic transistors based on conducting polymers offer a promising route to efficiently transduce ionic currents to attain high quality impedance spectra, but collection of complete impedance spectra can be time consuming (minutes). By applying uniform white noise at the gate of an organic electrochemical transistor (OECT), and measuring the resulting current noise, we are able to dynamically monitor the impedance and thus integrity of cultured epithelial monolayers. We show that noise sourcing can be used to track rapid monolayer disruption due to compounds which interfere with dynamic polymerization events crucial for maintaining cytoskeletal integrity, and to resolve sub-second alterations to the monolayer integrity.

No MeSH data available.


Short duration noise monitoring of MDCK I cell layer disruption with H2O2.Top: high pass filtered (1 Hz) drain current recording during addition of ~500 mM H2O2 to cultured MDCK I cells, Middle: Time-frequency analysis of the resulting transconductance (red: high, blue: low). Bottom: Magnitude of the transconductance at ~1 kHz. The resulting impedance change occurs over 250 μs, and is fully resolved by the measurement.
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f3: Short duration noise monitoring of MDCK I cell layer disruption with H2O2.Top: high pass filtered (1 Hz) drain current recording during addition of ~500 mM H2O2 to cultured MDCK I cells, Middle: Time-frequency analysis of the resulting transconductance (red: high, blue: low). Bottom: Magnitude of the transconductance at ~1 kHz. The resulting impedance change occurs over 250 μs, and is fully resolved by the measurement.

Mentions: To demonstrate rapid changes in impedance, we monitor the death/disruption of cells upon addition of a high concentration of hydrogen peroxide (H2O2). Jimison and co-workers24 previously explored the dynamic disruption of Caco-2 cell barriers with H2O2 using gate voltage pulses, for a broad range of concentrations. Addition of 50 and 100 mM resulted in disruption faster than the 30 s spacing of applied voltage pulses. Using this information we chose to add a concentration that was sufficiently high to rapidly disrupt the cells, while monitoring such dynamics using noise. By monitoring the noise frequency content we are able to track the death of the epithelial cells via the disruption of the barrier properties of the cell monolayer (Fig. 3). The MDCK I barrier functions are shown to degrade at ~t = 1.25 s by observing a rapid increase in the ID noise of the high-pass filtered (1 Hz) data. The frequency content of this current trace is visible via the time-frequency plot. From this data, we plot the transconductance at 1 kHz, alternatively, the cut off frequency could be quantified, or as above, the impedance (from IG measurements). Regardless of the choice of data displayed, the functionality of the cell layer disruption occurs in 250 μs, and is fully resolved. It should be noted that over the short-term duration of the disruption, the DC transconductance remains unchanged (~2 mS), indicating that over this time frame, the device performance is not affected by the H2O2, and that the observed change is due to the disruption of the cell barrier layer.


Using white noise to gate organic transistors for dynamic monitoring of cultured cell layers.

Rivnay J, Leleux P, Hama A, Ramuz M, Huerta M, Malliaras GG, Owens RM - Sci Rep (2015)

Short duration noise monitoring of MDCK I cell layer disruption with H2O2.Top: high pass filtered (1 Hz) drain current recording during addition of ~500 mM H2O2 to cultured MDCK I cells, Middle: Time-frequency analysis of the resulting transconductance (red: high, blue: low). Bottom: Magnitude of the transconductance at ~1 kHz. The resulting impedance change occurs over 250 μs, and is fully resolved by the measurement.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481393&req=5

f3: Short duration noise monitoring of MDCK I cell layer disruption with H2O2.Top: high pass filtered (1 Hz) drain current recording during addition of ~500 mM H2O2 to cultured MDCK I cells, Middle: Time-frequency analysis of the resulting transconductance (red: high, blue: low). Bottom: Magnitude of the transconductance at ~1 kHz. The resulting impedance change occurs over 250 μs, and is fully resolved by the measurement.
Mentions: To demonstrate rapid changes in impedance, we monitor the death/disruption of cells upon addition of a high concentration of hydrogen peroxide (H2O2). Jimison and co-workers24 previously explored the dynamic disruption of Caco-2 cell barriers with H2O2 using gate voltage pulses, for a broad range of concentrations. Addition of 50 and 100 mM resulted in disruption faster than the 30 s spacing of applied voltage pulses. Using this information we chose to add a concentration that was sufficiently high to rapidly disrupt the cells, while monitoring such dynamics using noise. By monitoring the noise frequency content we are able to track the death of the epithelial cells via the disruption of the barrier properties of the cell monolayer (Fig. 3). The MDCK I barrier functions are shown to degrade at ~t = 1.25 s by observing a rapid increase in the ID noise of the high-pass filtered (1 Hz) data. The frequency content of this current trace is visible via the time-frequency plot. From this data, we plot the transconductance at 1 kHz, alternatively, the cut off frequency could be quantified, or as above, the impedance (from IG measurements). Regardless of the choice of data displayed, the functionality of the cell layer disruption occurs in 250 μs, and is fully resolved. It should be noted that over the short-term duration of the disruption, the DC transconductance remains unchanged (~2 mS), indicating that over this time frame, the device performance is not affected by the H2O2, and that the observed change is due to the disruption of the cell barrier layer.

Bottom Line: These properties are critical for electrical detection of tissue health and viability in applications such as toxicological screening.By applying uniform white noise at the gate of an organic electrochemical transistor (OECT), and measuring the resulting current noise, we are able to dynamically monitor the impedance and thus integrity of cultured epithelial monolayers.We show that noise sourcing can be used to track rapid monolayer disruption due to compounds which interfere with dynamic polymerization events crucial for maintaining cytoskeletal integrity, and to resolve sub-second alterations to the monolayer integrity.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioelectronics, Ecole Nationale Superieure des Mines, CMP-EMSE, MOC, 13541 Gardanne, France.

ABSTRACT
Impedance sensing of biological systems allows for monitoring of cell and tissue properties, including cell-substrate attachment, layer confluence, and the "tightness" of an epithelial tissue. These properties are critical for electrical detection of tissue health and viability in applications such as toxicological screening. Organic transistors based on conducting polymers offer a promising route to efficiently transduce ionic currents to attain high quality impedance spectra, but collection of complete impedance spectra can be time consuming (minutes). By applying uniform white noise at the gate of an organic electrochemical transistor (OECT), and measuring the resulting current noise, we are able to dynamically monitor the impedance and thus integrity of cultured epithelial monolayers. We show that noise sourcing can be used to track rapid monolayer disruption due to compounds which interfere with dynamic polymerization events crucial for maintaining cytoskeletal integrity, and to resolve sub-second alterations to the monolayer integrity.

No MeSH data available.