TEER Research: WPI's Manual and Robotic Systems
Transepithelial Electrical Resistance TEER measurements is the most convenient, reliable and non-destructive method for evaluating and monitoring 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, including:
- EVOM² - Manual TEER measurement of epithelial cells in 24- and 96-well plates
- REMS AutoSampler - Automated system for High Throughput Screening (HTS)
The EVOM was the first instrument designed specifically to perform routine TEER (Trans Epithelial Electric Resistance) measurement in tissue culture research. Please note that the legacy EVOM and EVOMX were replaced by the updated EVOM2 in 2008. (For information on the new features, see EVOM2 Remix.) Features of the EVOM2 include:
- Battery powered electrically isolated meter
- AC current avoids adverse effects on tissue, which can otherwise be caused, by a DC current
- Compatible with Endohm chambers
- STX2 manual electrode included with meter (sterilize with EtO, alcohol or a bactericide)
- Easy-to-read LC display
- BNC output for data acquisition system
- Toggle switch for continuous measurement
One unique feature of the EVOM² is that resistance readings are unaffected by membrane capacitance and membrane voltage. The membrane voltage reading range is ±200 mV. EVOM² comes complete with the popular STX2 "Chopstick" electrode set. The STX2 consists of a fixed pair of double electrodes, 4mm 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 cell culture wells. STX2 can be used with all tissue culture inserts currently on the market. For higher accuracy measurements or lower resistance epithelia, the EVOM² can be used in conjunction with the optional Endohm chambers.
Automated TEER Measuring System
The REMS AutoSampler automates measurements of electrical resistance of transepithelial, transendothelial or Caco-2 cell membranes being grown to confluence on microporous filters of high throughput screening (HTS) 24- and 96-well microplates. It is a computer-controlled, tissue resistance measurement system that offers reproducibility, accuracy, flexibility and ease-of-operation for this kind of measurement.
Automated measurement of tissue resistance in cell culture microplates provides the important advantages of speed, precision, decreased opportunity for contamination and the instant availability of measured resistance data on a computer. These measurements are useful in applications such as drug bioavailability studies and studies on the mechanisms of drug transport.