Endohm™

TEER measurement chambers
Using WPI’s EVOM resistance meter, Endohm chambers provide reproducible resistance measurements of endo-thelial tissue 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.
Endohm’s symmetrically apposing 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 &Mac189; (when using WPI’s hand-held STX2 electrodes) to less than 5 &Mac189;. With Endohm’s fixed electrode geometry, variation of readings on a given sample is reduced from 10-30 &Mac189; with STX2 electrodes (depending on the experience of the user) to 1-2 &Mac189;. Compared with other resistance measurement methods, Endohm with EVOM offers a much more convenient and economic solution to “leaky tissue” measurement. Because of the uniform density of the AC square wave current from EVOM, errors owing to electrode polarization or membrane capacitance are largely eliminated. Endohm together with EVOM offers the most accurate and economical endothelial ohmmeter now available. To date, cups from Costar, Millipore, ICN Biomedicals, and Falcon have been tested. Endohm chambers may be sterilized with EtO, alcohol or a bactericide (also see: Cidex) not autoclavable.
ENDOHM-6 Endohm for 6 mm culture cups
ENDOHM-12 Endohm for 12 mm culture cups
ENDOHM-24SNAP Endohm for 24 mm & Costar Snapwell™ cup (6 wells per plate)

See EVOM™ epithelial voltohmmeter

See SynCel™cell culture cups with synthetic membrane.
References