Screening (HTS) cell culture filter plates EPITHELIAL PHYSIOLOGY Endohm™ For TEER measurement of endothelial cell cultures in individual cups ● Compatible with EVOM2 ● Improved accuracy of 1-2 Ohm ● Accommodates 6mm, 12mm, 24mm cups and Costar Snapwell cup ● Sterilized with EtO, alcohol or a bactericide duced 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 10-30 Ω with STX2 electrodes (depending on the experience of the user) to 1-2. 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 avail-able. 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, Microsurgery section); not autoclavable. Using WPI’s EVOM2 resistance meter, Endohm chambers provide reproducible resistance measurements of endothelial 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 voltagesensing silver/silver chloride pellet in the center plus an annular current electrode. The height of the top electrode can be adjusted ENDOHM-6 Endohm for 6 mm culture cup (24 wells per plate) to fit cell culture cups of different manufacture. Endohm’s ENDOHM-12 Endohm for 12 mm culture cup (12 wells per plate) symmetrically apposing circular disc electrodes, situated ENDOHM-24SNAP Endohm for 24 mm & Costar Snapwell™ cup (6 wells per plate) above and beneath the membrane, allow a more uniform Requires EVOM2, EVOM, EVOMX or Millicell ERS-2 current density to flow across the membrane than with STX2 53330-01 Replacement Endohm Cable electrodes. The background resistance of a blank insert is reUK: Tel: +44 (0)1462 424700 • wpiuk@wpi-europe.com World Precision Instruments www.wpiinc.com Germany: Tel: +49 (0)30-6188845 • wpide@wpi-europe.com US: Tel: 941-371-1003 • sales@wpiinc.com 83