Trans Epithelial Electric Resistance (TEER) Measurements During the last two decades TEER measurements have become universally established as the most convenient, reliable and non-destructive method to evaluate and monitor the growth of epithelial tissue cultures in vitro. The confluence of the cellular monolayer is quickly determined by a sharp increase in TEER. TEER measurement technology, which was first introduced by WPI in the mid-1980’s, has since been perfected and expanded to include a range of TEER related manual and automatic instrumentation. EVOM 2™ Epithelial Voltohmmeter ● Manual TEER measurements of epithelial cells in 6-, 12-, and 24-well plates ● Electrically isolated meter that plugs into a standard outlet for continual readout without push buttons ● Compatible with Endohm chambers ● STX2 manual electrodes and test electrode included with every meter ● Free standing with tilt bail, making viewing results easy The EVOM was the first instrument designed specifically to perform routine Trans Epithelial Electrical Resistance (TEER) measurement in tissue culture research. EVOM2 is the next generation, redesigned for ease of use. The EVOM2 not only qualitatively measures cell monolayer health, but also quantitatively measures cellular confluence. The unique electronic circuit of the EVOM2 and the included STX2 electrode detect the confluence of the cellular monolayer. When combined with WPI’s Endohm chamber, the EVOM2 can also be used to perform more accurate quantitative measurements or lower resistance measurements like transendothelial electrical resistance measurements. The isolated power source of the EVOM2 was specifically designed to avoid adverse effects on tissue and the formation of electrode metal deposits, even when it is plugged into a standard wall outlet. Now, the EVOM2 is always on when you need it. In addition, its rechargeable battery allows up to 10 hours of mobile use. The four and a half digit readout provides a range of 1-9,999 Ω. The included test electrode lets you calibrate the resistance measurements for an accurate reading every time, and the voltage meter never needs calibration. An analog BNC output is standard with the EVOM2, providing an output port for recording data or remote display of the EVOM2 output. EVOM2 comes complete with the popular STX2 “chopstick” electrodes, 4 mm wide and 1mm thick. Each stick of the electrode pair contains a silver/silver-chloride pellet for measuring voltage and a silver electrode for passing current. The small size of each electrode is designed to facilitate placement of the electrodes into a variety of standard cell culture wells. EPITHELIAL PHYSIOLOGY EVOM2 SPECIFICATIONS MEMBRANE VOLTAGE RANGE RESOLUTION RESISTANCE RANGE RESISTANCE RESOLUTION AC SQUARE WAVE CURRENT POWER 12 VDC NOMINAL BATTERY RUN TIME BNC OUTPUT DIMENSIONS WEIGHT ELECTRODE CONNECTION TEST RESISTOR ENVIRONMENTAL RANGE ±200 mV 0.1 mV 0 to 9999 Ω 1Ω ±10 µA nominal at 12.5 Hz Internal rechargeable 6V NiMH 2700 mAH battery with external supply for recharging 10 hours 1-10 V (1 mV/ohm) 19 x 11 x 6 cm (7.25” x 4.25” x 2.30”) 1.4 kg (3 lb) RJ-11connector (telephone style) External, 1000 Ω 10-38°C (50-100°F ) 0-90% non-condensing relative humidity STX2 STX3 EVOM2 Epithelial Tissue Voltohmmeter (includes STX2 electrode set) REPLACEMENTS AND ACCESSORIES STX2 Replacement “Chopstick” Electrode Set STX3 Adjustable Tip Spread “Chopstick” Electrode Set 3993 Electrode Adapter (for electrodes with 2 mm pins) 91736 Replacement Battery, Rechargeable NiMH 91750 EVOM2 Test Resistor UK: 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 81