WATCHING IT LIVE

Readouts built in

Instead of moving the cells to a separate instrument, a chip can carry the sensors with it. Electrodes track resistance, and a microscope watches tracers, all while the cells stay in flow.

A chip can read itself, hour after hour.

ELECTRODES

Thin metal films, made like microchips

How Gold, platinum, or silver/silver-chloride films are patterned by photolithography and metal deposition

Where One electrode in each channel, so current has to cross the cell layer

Layout A four-electrode setup separates the current path from the voltage sensing, which reduces contact errors

The tools that make microchips also make the sensors in a biology chip.

A WARNING

Chip TEER is not Transwell TEER

Electrode placement, channel shape, and the area the current covers all change the reading. A number measured in a chip can differ from the same cells measured in a Transwell, so values should not be compared without care.

Report how it was measured along with the number.

OPTICAL AND CHEMICAL

Beyond resistance

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Tracer imaging

Fluorescent dye shows where and when leakage starts

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Live cell imaging

Junction markers and cell shape can be watched over time

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Outflow sampling

Fluid leaving the chip is collected and analyzed to measure how much drug crossed

A transparent chip makes every readout easier.

WHY IT MATTERS

Continuous, gentle monitoring

Built-in sensors give a time series instead of a single snapshot. You can watch a barrier mature for days, see the moment a drug or an inflammatory signal loosens it, and then see whether it recovers.

The question shifts from is it tight, to how does it change.

UNIT 15 STUDY COMPLETE

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Ready for the Fab Challenge?

You've seen how electrodes and imaging are built into a chip to watch a barrier over days.