Cellular barriers formed by endothelial and epithelial cells regulate movement of substances like molecules, pathogens, and therapeutic compounds between distinct physiological environments. Changes in barrier integrity are important in inflammation, infection, gastrointestinal and respiratory disease, and drug response.
Axion BioSystems’ Maestro Z platform continuously measures barrier formation, disruption, and recovery using label-free impedance.
Measure barrier integrity continuously with real-time, label-free impedance
Run real-time barrier function assays in 96- or 384-well formats to support both mechanistic studies and higher-throughput screening.
- Measure continuously rather than relying on isolated endpoint measurements.
- Monitor barrier formation, disruption, and recovery in the same cell population.
- Separate barrier integrity from cell coverage to better interpret changes.
- Reduce manual handling with integrated electrodes and automated measurements.
- Scale from 96 to 384 wells for high throughput without changing core assay approach.
- Maintain physiological conditions with integrated environmental control.
Barrier Function Assays
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Normalize TEER to cell coverage with Barrier Index>
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Track barrier disruption and recovery in real time>
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Measure functional responses in disease models>
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Study host-microbiome interactions dynamically>
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Scale barrier function assays from 96 to 384 wells>
The Maestro Z platform simultaneously measures cell coverage and barrier resistance using multi-frequency impedance measurements.
Axion’s Barrier Index normalizes barrier resistance relative to cell coverage, helping researchers distinguish changes in tight-junction function from changes associated with cell attachment or coverage.
This approach can improve sensitivity when measuring small or transient disruptions in cellular barriers.
For example, two cell cultures may reach similar levels of confluence but develop very different barrier properties. Measuring both parameters helps distinguish a confluent monolayer from a functionally intact cellular barrier.
Barrier responses can occur over minutes, hours, or days. A single endpoint measurement may therefore miss important differences in the timing or magnitude of a response.
Continuous impedance measurements reveal the complete response profile.
Researchers can observe:
establishment of the cellular barrier
onset of barrier disruption
magnitude of the response
transient versus sustained effects
recovery of barrier integrity
differences in response kinetics between treatments
For example, Calu-3 epithelial monolayers treated with cytochalasin D or ethanol show decreases in TEER, but the treatments produce distinct response kinetics. Continuous monitoring makes these differences directly observable.
(A) Barrier permeability can be measured continuously from proliferation to confluence. (B) Calu-3 monolayers were cultured for 14 days in the CytoView-Z 96-well plate and then treated with cytochalasin D and ethanol, both of which significantly reduced the TEER.
Barrier measurements can provide functional information that extends beyond cell coverage alone.
For example, Calu-3 cells express functional cystic fibrosis transmembrane conductance regulator (CFTR). Changes in ion transport associated with CFTR activation by β-adrenergic stimulation can be detected through changes in electrical resistance.
Real-time measurements can therefore be used to investigate both the response and mechanism of action in disease-relevant cellular models.
(A) Addition of isoproterenol (teal, 100 nM) and forskolin (orange, 10 µM) significantly reduced TEER of the Calu-3 cells. CFTR(inh)-172 was then added to the plate at 30 and 300 µM causing a rapid dose-dependent reversal of the isoproterenol and forskolin response. (B) 5 minutes after CFTR(inh)-172 addition isoproterenol and forskolin responses are inhibited in a dose-dependent manner.
Interactions between microorganisms and epithelial tissue can produce changes in barrier function that develop over time.
Continuous impedance measurements make it possible to compare the magnitude and kinetics of these responses across microbial species or strains.
In published research using Axion’s impedance technology, Bifidobacterium adolescentis isolates produced strain-dependent reductions in intestinal epithelial barrier function, while Bacteroides fragilis did not produce the same response. These results aligned with immunostaining of the tight-junction protein ZO-1, providing supplementary evidence of disrupted barrier function.
(Images from H Bootz-Maoz, A. Pearl et al, Cell Reports, 2022, DOI: https://doi.org/10.1016/j.celrep.2022.111657 )
Barrier function studies increasingly require researchers to evaluate more compounds, concentrations, conditions, donors, or biological models within a single experiment.
Axion BioSystems supports both 96- and 384-well impedance-based barrier function assays, allowing researchers to select the throughput appropriate for their study.
96-well barrier function assays
The 96-well format is well suited for mechanistic experiments, assay development, concentration-response studies, and experiments requiring multiple treatment conditions or biological replicates.
384-well barrier function assays
The 384-well format enables higher-throughput barrier function studies while maintaining real-time, continuous impedance measurements.
With the Maestro ZHT, researchers can collect up to 384 simultaneous live recordings, making it possible to evaluate substantially more experimental conditions while capturing the kinetics of each response.
Multi-plate 96-well barrier function assays
The Maestro TrayZ enables simultaneous barrier function measurements across up to eight 96-well plates, increasing throughput while retaining the flexibility and familiarity of the 96-well format.
The ability to perform continuous barrier function measurements in both 96- and 384-well formats provides a path from assay development to higher-throughput screening on the same impedance-based approach.
Applications of barrier function assays
Real-time barrier function measurements can be applied across a range of biological models and research questions.
>> Intestinal barrier function
Measure the formation and disruption of intestinal epithelial barriers and investigate responses to microbial species, microbial metabolites, inflammatory stimuli, compounds, and disease-associated conditions.
>> Airway and lung epithelial barriers
Monitor epithelial barrier formation and changes in models relevant to respiratory biology and disease.
>> Endothelial barrier function
Measure changes in endothelial monolayers associated with vascular permeability, inflammation, compound response, viral infections, or disease models.
>> Blood-brain barrier models
Evaluate changes in barrier integrity in cellular models designed to investigate the selective permeability of the blood-brain barrier.
>> Drug and compound testing
Compare the concentration-dependent and time-dependent effects of compounds on barrier integrity and recovery.
>> Host-microbiome interactions
Monitor dynamic changes in epithelial barrier function following exposure to bacterial species, strains, microbial products, or other components of the microbiome.
“The Teer assay is a game-changer in cell barrier research.”
The Teer assay is a vital tool for unraveling the mysteries of cellular barriers and advancing our understanding of health and disease in the easiest way possible. We utilize the Maestro Edge system with the Impedance Module to measure TEER in colonic epithelial cells cultured with various bacteria in vitro. Recently, we demonstrated that B. adolescentis bacteria impair epithelial barrier integrity in patients with irritable bowel syndrome (IBS).
- Hadar Bootz-Maoz. Bar Ilan University, Ramat Gan, Israel
Featured resources for barrier function research
Explore selected application notes, publications, webinars, and technical resources demonstrating how real-time impedance can be used to investigate cellular barrier function.
TEER with Maestro Z Application Note
Multiplate cell-based assays with Maestro TrayZ for cytotoxicity and potency
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Learn how Maestro Z platforms enable simple and reliable measurements of TEER.
Frequently asked questions about barrier function assays
TEER is an electrical measurement used to assess the resistance of a cellular barrier. Barrier function is the broader biological property describing how effectively a cell layer regulates movement across the barrier.
TEER can therefore be used as one quantitative measurement of barrier integrity.
Yes. Integrated-electrode impedance systems such as the Maestro Z can measure electrical resistance continuously while traditional TEER methods require without repeatedly inserting a handheld electrode into the culture.
Continuous measurements provide richer datasets; revealing when changes occur, the rate of change, and whether the barrier subsequently stabilizes or recovers.
Electrical impedance measured at different frequencies provides information about different characteristics of the cell layer. Low-frequency measurements are particularly sensitive to barrier resistance, while higher-frequency measurements can provide information about cell coverage.
Combining these measurements helps distinguish changes in barrier integrity from changes in cell coverage.
Barrier Index is a unique, impedance-derived metric provided by the Maestro Z platform. It relates barrier resistance to cell coverage, helping researchers determine whether changes in resistance reflect altered barrier properties rather than simply differences in the amount of cell coverage.
Yes. Axion BioSystems’ Maestro ZHT supports real-time, label-free barrier function measurements in both 96- and 384-well plate formats.
The 384-well format enables higher-throughput experiments while preserving continuous measurements of the cellular response.
Barrier function assays are commonly performed with epithelial and endothelial cells. The appropriate model depends on the tissue and biological question being investigated and may include intestinal, airway, vascular, or other barrier-forming cell types.
Continuous measurements reveal the kinetics of barrier formation, disruption, and recovery. They can identify transient responses or differences in timing that may be missed when measurements are collected only at predetermined endpoints.
