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Benefits

• Stability and reproducibility superior to the STX2 electrodes to 1% tolerance
• Can be used with 6, 12 or 24 well plates with removable inserts
• Symmetrical electrode pattern disperses test current uniformly
• Tri-leg supports offer mechanical stability and the membrane is held parallel to the electrodes(G version)
• Simple test procedure to verify electrode performance

Applications

• TEER measurement for removable culture cup systems using EVOM2™ meters for endothelial and epithelial cell cultures

TEER measurement in individual cups

Using WPI’s EVOM2™ resistance meter, Endohm chambers provide reproducible resistance measurements of endothelial and epithelial monolayers in culture cups. Transfer cups from their culture wells to the Endohm chamber for measurement rather than using hand-held electrodes. The chamber and the cap each contain a pair of concentric electrodes: a voltage-sensing silver/silver chloride pellet in the center plus an annular current electrode. The height of the top electrode can be adjusted to fit cell culture cups of different manufacture.

Make more precise measurements with Endohms

Endohm’s symmetrically opposing circular disc electrodes, situated above and beneath the membrane, allow a more uniform current density to flow across the membrane than with STX2 electrodes. The background resistance of a blank insert is reduced from 150 Ω (when using WPI’s hand-held STX2 electrodes) to less than 5 Ω. With Endohm’s fixed electrode geometry, variation of readings on a given sample is reduced from 10-30Ω with STX2 electrodes (depending on the experience of the user) to 1-2 Ω. Compared with other resistance measurement methods, Endohm with EVOM2™ offers a much more convenient and economic solution to “leaky tissue” measurement. Because of the uniform density of the AC square wave current from EVOM2™, errors owing to electrode polarization or membrane capacitance are largely eliminated. Endohm together with EVOM2™ offers the most accurate and economical endothelial ohmmeter now available. To date, cups from Corning, Millipore, Nunc, Greiner and BD Falcon have been tested. Endohm chambers may be sterilized with EtO, alcohol or a bactericide; not autoclavable.

Compatibility Charts

The ENDOHM-6G is compatible with the following chambers:

* The tri-supports overhang the chamber edge and the well cannot be held parallel to the electrodes.

The ENDOHM-12G is compatible with the following chambers:

* The tri-supports legs must be balance correctly so that the filter is parallel to the electrodes.

The ENDOHM-24SNAP is compatible with the following chambers:

* The tri-support legs must be balanced correctly so that the filter is parallel to the electrodes.

Frequently Asked Questions