TEER Measurement Techniques for In Vitro Barrier Model Systems (original) (raw)
Related papers
BioTechniques, 2004
Measurement of transendothelial or transepithelial electrical resistances (TERs) is a straightforward in situ experimental approach to monitor the expression or modulation of barrier-forming cell-to-cell contacts (tight junctions) in cultured cells grown on porous filters. Although widely accepted, there is currently no device available to automatically measure the time course of TERs under ordinary cell culture conditions (37°C, 5% or 10% CO2). This paper describes a development from our laboratory that is capable of following in parallel the TERs of several filter-grown cell layers with time and in an entirely computer-controlled fashion. The cell cultures can be followed even in long-term experiments without any manual assistance or opening of the incubator. Besides reading TER values, this approach also returns the electrical capacitance of the cell layers, which is indicative of the expression of microvilli and other membrane extrusions. The device is based on reading the frequ...
Analytical Chemistry, 2010
This manuscript describes a straightforward fabrication process for embedding Ag/AgCl electrodes within a twolayer poly(dimethylsiloxane) (PDMS) microfluidic chip where an upper and a lower channel are separated by a semiporous membrane. This system allows for the reliable real-time measurement of transendothelial and transepithelial electrical resistance (TEER), an accepted quantification of cell monolayer integrity, across cells cultured on membranes inside the microchannels using impedance spectroscopy. The technique eliminates the need for costly or specialized microelectrode fabrication, enabling commercially available wire electrodes to easily be incorporated into PDMS microsystems for measuring TEER under microfluidic environments. The capability of measuring impedance across a confluent cell monolayer is confirmedusing(i)brain-derivedendothelialcells bEND.3), (ii) Madin Darby Canine Kidney Cells (MDCK-2), and mouse myoblast (C2C12) (all from ATCC, Manassas, VA). TEER values as a function of cell type and cell culture time were measured and both agree with previously published values from macroscale culture techniques. This system opens new opportunities for conveniently resolving both transendothelial and transepithelial electrical resistance to monitor cell function in real-time in microfluidic cell cultures.
Scientific Reports, 2016
The most frequently used parameters to describe the barrier properties of endothelial cells (ECs) in vitro are (i) the macromolecular permeability, indicating the flux of a macromolecular tracer across the endothelium, and (ii) electrical impedance of ECs grown on gold-film electrodes reporting on the cell layer's tightness for ion flow. Due to the experimental differences between these approaches, inconsistent observations have been described. Here, we present the first direct comparison of these assays applied to one single cell type (human microvascular ECs) under the same experimental conditions. The impact of different pharmacological tools (histamine, forskolin, Y-27632, blebbistatin, TRAP) on endothelial barrier function was analyzed by Transwell ® tracer assays and two commercial impedance devices (xCELLigence ® , ECIS ®). The two impedance techniques provided very similar results for all compounds, whereas macromolecular permeability readings were found to be partly inconsistent with impedance. Possible reasons for these discrepancies are discussed. We conclude that the complementary combination of both approaches is highly recommended to overcome the restrictions of each assay. Since the nature of the growth support may contribute to the observed differences, structure-function relationships should be based on cells that are consistently grown on either permeable or impermeable growth supports in all experiments. The vascular endothelium, a cell monolayer lining the blood vessels, operates as a size-selective and semi-permeable extravasation filter for plasma proteins, solutes, and fluids, thus controlling tissue homeostasis 1. Dysfunction of the endothelial barrier, e.g. by opening intercellular junctions, and the subsequent edema formation is a hallmark of inflammatory processes and associated with a plethora of severe diseases, e.g. atherosclerosis, rheumatoid arthritis, or asthma. Unfortunately, anti-edematous drugs that specifically interact with barrier-regulating processes in endothelial cells have not been described yet. Consequently, there is a great need for basic research and drug discovery programs involving both academic and industrial partners. Both, the in-depth elucidation of endothelial barrier regulation and the comprehensive screening of potential anti-edematous compounds must be pursued. Quantitative, sensitive, and high-throughput approaches are, thus, required to monitor barrier properties of endothelial cell monolayers in vitro mimicking physiological and patho-physiological conditions. Two techniques have been considered as gold standard throughout the last decades: (i) Measurement of macromolecular permeation (e.g. of fluorescence-labeled dextran) across a vascular endothelial cell layer as direct indicator for transendothelial solute flux and (ii) determination of transendothelial electrical resistance (TER) as measure for ionic permeability through intercellular clefts 2-9. Both approaches have their individual advantages and limitations with respect to their sensitivity, time resolution, artifacts, and practicability. For either type of
Micromachines, 2021
The blood–brain barrier (BBB) represents the tightest endothelial barrier within the cardiovascular system characterized by very low ionic permeability. Our aim was to describe the setups, electrodes, and instruments to measure electrical resistance across brain microvessels and culture models of the BBB, as well as critically assess the influence of often neglected physical and technical parameters such as temperature, viscosity, current density generated by different electrode types, surface size, circumference, and porosity of the culture insert membrane. We demonstrate that these physical and technical parameters greatly influence the measurement of transendothelial electrical resistance/resistivity (TEER) across BBB culture models resulting in severalfold differences in TEER values of the same biological model, especially in the low-TEER range. We show that elevated culture medium viscosity significantly increases, while higher membrane porosity decreases TEER values. TEER data...
Two-Path Impedance Spectroscopy for Measuring Paracellular and Transcellular Epithelial Resistance
Biophysical Journal, 2009
Solutes are transported across epithelial cell layers via transcellular and paracellular pathways. The transcellular pathway leads across the apical and basolateral cell membrane, whereas the paracellular pathway is directed through the tight junction. Tight junction proteins (claudins, occludin, tricellulin) can not only form barriers but also paracellular channels that arein concert with membrane channels and transporters-regulated in a wide range in health and disease states. Thus, it is desirable to determine para-and transcellular resistance (R para , R trans ) separately. This cannot be achieved by conventional transepithelial resistance (TER) measurements. We present an impedance spectroscopic approach that is optimized for differentiation between these two pathways. The method is based on a transepithelial impedance measurement in specialized Ussing chambers, combined with a Ca 2þ -dependent modulation of R para through EGTA and flux measurements of a nonradioactive paracellular marker, fluorescein. The prerequisites are a paracellular marker that varies in parallel to 1/R para , an experimental regime that alters R para without affecting R trans , and exact knowledge of the resistance of subepithelial components. The underlying prerequisites and the applicability as a routine method were verified on cell lines of different tightness including HT-29/B6 colon cells and Madin-Darby canine kidney tubule cells C7 and C11.
Direct quantification of transendothelial electrical resistance in organs-on-chips
Biosensors & bioelectronics, 2016
Measuring transendothelial or transepithelial electrical resistance (TEER) is a widely used method to monitor cellular barrier tightness in organs-on-chips. Unfortunately, integrated electrodes close to the cellular barrier hamper visual inspection of the cells or require specialized cleanroom processes to fabricate see-through electrodes. Out-of-view electrodes inserted into the chip's outlets are influenced by the fluid-filled microchannels with relatively high resistance. In this case, small changes in temperature or medium composition strongly affect the apparent TEER. To solve this, we propose a simple and universally applicable method to directly determine the TEER in microfluidic organs-on-chips without the need for integrated electrodes close to the cellular barrier. Using four electrodes inserted into two channels - two on each side of the porous membrane - and six different measurement configurations we can directly derive the isolated TEER independent of channel prope...
Experimental Cell Research, 1999
Transepithelial resistance (TER) measurement has often been used to study the paracellular transport properties of epithelia grown on permeable filters, especially the barrier function of tight junctions. However, the TER value includes another source, the resistance caused by cell-substrate contact, that may give rise to a high TER value if cell-substrate separation is small. In this study we use electric cell-substrate impedance sensing (ECIS) to measure both paracellular resistance and the average cell-substrate distance of MDCK (II), HEp-2, and WI-38 VA13 cells. Comparing ECIS data with those from TER measurements of cell layers cultured on polycarbonate filters, we can obtain the approximate extra resistance resulting from cell-substrate contact for each cell type. The value of cell-substrate resistance was also estimated by two theoretical calculations that bracket the true values. Our results demonstrate that cell-substrate contact substantially influences the TER data measured using polycarbonate filters and that the extra resistance due to cell-substrate spaces depends on both cell type and filter property.
Scientific Reports
Epithelial and endothelial barrier function is typically studied in vitro by growing the cells of interest on permeable supports that are sandwiched between two fluid compartments. This setup mimics the physiological situation with the cell layer as the diffusion barrier at the interface between two chemically distinct fluids. Routinely, the barrier function is quantitatively described by two key parameters: (i) the transepithelial or transendothelial electrical resistance (TER) as a measure of the permeability for small inorganic ions and (ii) the permeability coefficient (PE) as a descriptor of the permeability for molecular tracers. So far the two parameters have been determined in separate experiments. This study introduces a device that allows for simultaneous detection of PE and TER of the very same cell monolayer in one single experiment (PETER-assay). The novel approach is entirely based on AC impedance measurements in two different modes, so that TER and PE become available...
Biosensors, 2018
In this paper, we demonstrate the application of electrical cell-substrate impedance sensing (ECIS) technology for measuring differences in the formation of a strong and durable endothelial barrier model. In addition, we highlight the capacity of ECIS technology to model the parameters of the physical barrier associated with (I) the paracellular space (referred to as R) and (II) the basal adhesion of the endothelial cells (α, alpha). Physiologically, both parameters are very important for the correct formation of endothelial barriers. ECIS technology is the only commercially available technology that can measure and model these parameters independently of each other, which is important in the context of ascertaining whether a change in overall barrier resistance (R) occurs because of molecular changes in the paracellular junctional molecules or changes in the basal adhesion molecules. Finally, we show that the temporal changes observed in the paracellular R can be associated w...