Abstract
Purpose: :
To determine how the electrical resistance and capacitance of the human epithelial conjunctival cell line (IOBA-NHC) monolayer is affected by changes in the media osmolarity
Methods: :
Electric cell-substrate impedance sensing (ECIS) was used to measure electrical resistance and capacitance across cultured human conjuntive epithelial cell line IOBA-NHC monolayers. After a 1-hour equilibration period, different concentrations of NaCl were added to the ECIS well, and the effect observed for 1 hour. We added 2, 4 and 8 mg/ml of NaCl to the standard media in parametric runs to change the media osmolarity to 360 mOsm/L, 446 mOsm/L and 617 mOsm/L, respectively.
Results: :
Increase of hyperosmolarity significantly decreased the resistance of the naked electrode, whereas the capacitance remains unchanged. The resistance with the cell monolayer is about three times the value of the naked electrode to hyperosmolarity 360 mOsm/L, 446 mOsm/L and 617 mOsm/L. The capacitance curves also reflects the presence of the cells attached to the substrate for high excitation frequency. The ECIS technique also detected a very important contrast at different osmolarity condition with the monolayer cell covered electrode.
Conclusions: :
ECIS technique is capable to detect small changes in osmolarity through changes in resistance and capacitance for cell measurements and through changes in resistance for naked electrode measurements.The optimum value for the ECIS [600-700]Hz to maximize contrast between cell covered and naked electrode. The frequency value to maximized contrast between measurements with cells covered microelectrode and different NaCl concentration is near 500Hz.
Keywords: pathology techniques • conjunctiva • cornea: tears/tear film/dry eye