How is Transepithelial resistance measured?
Transepithelial resistance (TER) can be determined, as a repetitive screening method, by chopstick electrodes directly on cell culture filters or, as a more reliable technique, in Ussing chambers.
What is a TEER value?
TEER values are strong indicators of epithelial cell barrier integrity and permeability, and often used for evaluating transport of potential drug chemicals and related in vitro drug screening assays.
How do you measure TEER?
Traditionally TEER is measured by manually placing two chopstick-style electrodes on each side of a confluent cell layer. A low frequency current is applied and the resistance of the barrier is measured. The easier the current flows between the cells the lower the TEER value.
What is the tight junction?
A tight junction is a type of cell junction wherein the membranes of two neighboring cells join to form a barrier to larger molecules and water that pass between the cells. As a barrier, tight junctions help maintain the polarity of cells and the osmotic balance.
What is Transepithelial?
Medical Definition of transepithelial : existing or taking place across an epithelium transepithelial sodium transport.
How is Transendothelial electrical resistance measured?
Transendothelial (or epithelial) electrical resistance (TEER) is a non-invasive measure of the tightness of a cellular barrier. In organs-on-chips, TEER is often measured using two electrodes that are placed on either side of a porous membrane on which cells are cultured.
What do Occludins do?
Function. Occludin is an important protein in tight junction function. Studies have shown that rather than being important in tight junction assembly, occludin is important in tight junction stability and barrier function.
What is an example of tight junction?
Tight epithelia have tight junctions that prevent most movement between cells. Examples of tight epithelia include the distal convoluted tubule, the collecting duct of the nephron in the kidney, and the bile ducts ramifying through liver tissue.
What is Zona Occludens?
ZO (zonula occludens) proteins are scaffolding proteins providing the structural basis for the assembly of multiprotein complexes at the cytoplasmic surface of intercellular junctions. In addition, they provide a link between the integral membrane proteins and the filamentous cytoskeleton.
How does transepithelial potential difference work?
Solute transport provides a transepithelial potential difference, where the electrical resistance depends on the tightness of the junctional complexes between cells. The greater the unidirectional transport of charged particles across an epithelial barrier, the higher the potential difference.
How is Transepithelial potential difference measured?
The bioelectric potential can be measured by using a high-impedance voltmeter between two electrodes, with one in continuity with each side of the epithelial surface. The electrode on the airway surface (the exploring electrode) rests against the surface of the target epithelium.
Is occludin a protein?
How is the transepithelial electrical resistance ( Teer ) measured?
Transepithelial electrical resistance (TEER) measurement is used to assess the barrier function of epithelial cells on these porous supports. When assessing the electrical impedance, a continuous current passes through the cells on both transcellular and paracellular paths (Powell 1981 ).
How are Teer measurements used to study epithelial barrier function?
Thus, TEER measurements are often used to study epithelial barrier function. The electrode is placed in the medium in the upper chamber, and resistance is directly measured by a portable voltmeter like the Millicell-ERS Voltmeter.
Which is the best epithelial voltohmmeter for Teer?
(Millipore) or the EVOM2, Epithelial Voltohmmeter for TEER (World Precision Instruments Inc., Sarasota, FL) (see Figs. 9.3 and 9.4, respectively). If the culture is to be continued, the electrode should be sterilized with 70 % ethanol.
What makes up the transcellular and paracellular resistance?
The transcellular resistance is primarily made up by the apical and basolateral plasma membrane, while the paracellular resistance is a result of cell–substrate as well as cell–cell contacts. It is known that specific tight junction proteins largely influence epithelial resistance (Anderson 2001; Lo et al. 1999).