Effects of osmolarity on human epithelial conjunctival cells using an electrical technique

The purpose of this study is to report the effect of different media osmolarity on a cell line monolayer of normal human conjunctival epithelia (IOBA-NHC) using Electric Cell-substrate Impedance Sensing (ECIS).

We built our own ECIS system. We fabricated biocompatible microelectrodes. We used a monolayer of IOBA-NHC cells with media at different osmolarities (315, 360, 446, and 617 mOsm/l).

When there is an increase in hyperosmolarity, there is a slight decrease in the measured resistance of the naked microelectrode (without cells), whereas its capacitance remained practically unchanged. The evaluation of resistance and capacitance of a microelectrode covered by a monolayer of IOBA-NHC in relation to a naked microelectrode showed no difference in the standard media (315 mOsm/l), a small difference with 360 mOsm/l, and significant differences with hyperosmolarities of 446 mOsm/l and 610 mOsm/l. The resistance with a confluent cell monolayer is up to three times greater compared to the value of the resistance of the naked electrode with standard media.

Both resistance and capacitance measurements for the cell monolayer were sensitive to changes in osmolarity.