The information i found from the literature is that a small AC signal is used to measure the strength of your tight junctions in you cellular monolayer. The chopsticks are Ag/AgCl electrodes, and the low current used is 10µA. The cells are grown in an insert which allows the chopsticks to be on either side of the layer of cells, the current passes through, and you can then use Ohms law to calculate the resistance and therefore your barrier function.
I'm not an expert in electronics, but as the commercial version of the equipment is very expensive, I'm looking into cheaper alternatives - assuming it is possible.
The following is the tech specs from the company that manufactures them:
MEMBRANE VOLTAGE RANGE ±199.0 mV
VOLTAGE MEASUREMENT 0.1mV
RESISTANCE RANGES 0 to 9999 ohm
RESISTANCE RESOLUTION 1 ohm
AC SQUARE WAVE CURRENT ±10 µA at 12.5 Hz
POWER Internal rechargeable 6V NiMH 2200 mAH battery with external 12VDC supply for recharging
SHIPPING WEIGHT 3 lb (1.4 Kg)
ELECTRODE CONNECTION RJ-11 Connector (telephone style)
TEST RESISTOR External
ENVIRONMENTAL RANGE 10-38 C (50-100 F) 0 - 90% non-condensing relative humidity
Would be good to get an idea if this is worth pursuing, or there's a reason why I can't find someone thats tried it!