What is TEER?

TEER measurement researcher

 

Transepithelial/Endothelial Electrical Resistance (TEER) qualitatively measures cellular monolayer health and quantitatively evaluates cellular confluence by measuring the electrical resistance across a cell monolayer. It is commonly used to assess the integrity and permeability of cellular barriers, such as epithelial and endothelial cell layers in cell culture plates. Organ-on-Chip platforms are an emerging market for TEER applications. Let’s look at what TEER is and how it is used.

What is TEER?

TEER is a measure of the resistance to the flow of ions across a cell layer grown on a porous membrane. It reflects the tightness of the cell junctions and the barrier function of the cell layer. Higher TEER values indicate tighter junctions and a less permeable barrier, while lower TEER values suggest looser junctions and a more permeable barrier. When culturing cells in a well plates, TEER can be used to determine cellular confluence. When the TEER value rises steeply, confluence has been achieved and then barrier studies may begin.

 

How is TEER Measured?

TEER is typically measured using a probe with a pair of electrodes placed on either side of the cell monolayer, one in the apical compartment (above the cells) and one in the basolateral compartment (below the cells). An electronic instrument like the EVOM™ Auto or EVOM™ Manual applies a small, defined voltage across the electrodes and measures the resulting current, from which the resistance can be calculated.

The TEER value is calculated using Ohm's Law (R = V/I), where R is resistance, V is voltage, and I is current. It is usually reported in units of ohms times square centimeters (Ω·cm²) to account for the area of the cell monolayer.

Applications of TEER

TEER measurement meters designed and manufactured by WPI, including the EVOM™ family of products and the Millipore Millicell ERS and ERS-2 meters, have been cited in over 16,000 research papers for a large variety of applications. Some popular applications include:

  • Epithelial Barrier Function – TEER lets researchers evaluate the integity and function of cellular barriers.
  • Drug Absorption Studies – TEER is used to evaluate how drugs or other compounds affect the integrity of cell layers, improving in the development of pharmaceutical drugs and supplements. TEER helps assess the potential toxicity of chemicals on cellular barriers.
  • Tissue Engineering & Cell Culture – TEER helps researchers doing tissue engineering  to assess the formation and functionality of the epithelial cell layers.
  • Disease Modeling – TEER measurements is used to model diseases that affect barrier function, such as inflammatory bowel disease or blood-brain barrier dysfunctions.
  • Quality Control in Cell-Based Assays and Cell Therapies – TEER is an excellent method for monitoring quality control in cell-based assays using endothelial or epithelial barrier tissues. 
  • Nutrient Transport Studies –TEER helps in the study the transport of nutrients and other molecules across cell layers.

Advantages of TEER

TEER measurements is a method of choice for several key reasons. First, TEER is non-invasive and does not harm the cells. TEER also provides precise, numerical data on barrier integrity. And, with an automated system, measurements can be taken quickly, facilitating high-throughput screening. WPI’s EVOM™ products offer hands-free operations. Simple, portable manual systems are available, as well as automated systems for 24-well plates favored in a university setting and 96-well plate systems used in pharmaceutical research.

Scope of TEER

TEER measurements are sensitive to various factors such as temperature, pH, and electrode placement, which can affect measurements. Plate readings are much quicker in both the EVOM™ Auto and EVOM™ Manual systems than for older models, mitigating some of the environmental factors which can affect TEER. The EVOM™ Auto’s autosampler ensures consistent electrode placement with every measurement. EVOM™ Manual’s electrode likewise has been designed for consistent placement and repeatable measurements.

TEER measurements give insight into the permeability of the cell monolayer using a resistance value, but it is not designed to provide specific information about which tight junction proteins are involved or how they are altered.

Summary

TEER is a valuable tool in cell biology and pharmacology for assessing the barrier function of epithelial and endothelial cell layers. Its non-invasive nature and quantitative output make it ideal for various research applications. WPI designed the first TEER measurement meter almost 40 years ago. Today, with its proven track record, WPI’s EVOM™ technology, the gold-standard for TEER, is trusted by researchers around the globe. 

 

Details on TEER

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