A Simple Approach to Perform TEER Measurements Using a Self-Made Volt-Amperemeter with Programmable Output Frequency
October 5th, 2019
22.4K views
Here, we demonstrate how to set up an inexpensive volt-amperemeter with programmable output frequency that can be used with commercially available chopstick electrodes for transepithelial/endothelial electrical resistance measurements.
Overview
This study presents a cost-effective method for measuring transepithelial electrical impedance using a programmable volt-amperemeter designed for use with chopstick electrodes. The approach enhances the accessibility of resistance measurements in epithelial monolayers, which are critical for assessing barrier function in cell culture.
Key Study Components
Research Area
- Cell biology
- Electrical impedance measurements
- Barrier function assessment
Background
- Measurement of transepithelial electrical impedance has been utilized since the 1980s to evaluate epithelial monolayers.
- Standard devices for this measurement can be costly and may not offer adaptable output frequencies.
- This study presents an affordable alternative that maintains precision and reliability.
Methods Used
- The assembly of a volt-amperemeter using standard electronic components.
- Choroid plexus epithelial papilloma cells cultured on Transwell filters as the model system.
- Implementation of four-terminal sensing to improve measurement accuracy.
Main Results
- The assembled volt-amperemeter provided reliable impedance readings, with measured values closely matching reference values.
- Electrical impedance measurements exhibited a range of reliability from 0 to 1.8 kiloohms.
- Measurement outcomes validated the device's utility for both initial experiments and further studies.
Conclusions
- This study demonstrates a feasible and low-cost solution for conducting electrical resistance measurements in cell cultures.
- The findings are significant for advancing techniques in biological research and the assessment of cell layer properties.
Frequently Asked Questions
What is a transepithelial electrical impedance measurement?
It is a technique used to assess the barrier function and confluency of cell monolayers by measuring their electrical resistance.
Why is the volt-amperemeter considered cost-effective?
It can be assembled using inexpensive, commercially available electronic components, reducing the overall cost compared to standard devices.
What types of cells were used in the study?
Choroid plexus epithelial papilloma cells were cultured on Transwell filters to serve as the biological model.
How does the four-terminal sensing work?
It utilizes separate pairs of electrodes for current delivery and voltage measurement, minimizing errors in impedance calculation.
What applications can this measurement technique have?
It can be used in various biological research areas, specifically for assessing barrier properties in cell culture experiments.
Can the volt-amperemeter be utilized for other types of measurements?
While it is tailored for transepithelial resistance, variations could allow for other electrical measurements depending on receptor configurations.
What is the significance of measuring electrical impedance?
Electrical impedance provides insights into cell health, confluency, and the effectiveness of barrier functions in various biological studies.
Executive Industry Relevance
Cost-effective and programmable TEER measurement solutions enable scalable assessment of epithelial barrier function, supporting early-stage target validation and mechanistic de-risking in drug discovery. By providing reliable quantitative impedance data, this approach enhances predictive confidence in preclinical models of blood-brain, blood-cerebrospinal fluid, gastrointestinal, and pulmonary barriers. The method supports portfolio triage by reducing biological uncertainty in lead identification workflows.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses through quantitative assessment of barrier integrity in disease-relevant cell models.
- Operational Value: Supports functional target validation by correlating genetic or pharmacological perturbations with measurable changes in transepithelial resistance.
- Predictive Value: Facilitates mechanistic de-risking by providing reproducible, frequency-programmable impedance readouts that reflect tight junction formation and monolayer health.
Screening & Assay Development
- Scientific Value: Delivers standardized, quantitative outputs for assessing compound effects on barrier function in high-throughput compatible formats.
- Operational Value: Enables assay reproducibility through programmable output frequency and four-terminal sensing, minimizing measurement variability across runs.
- Scalability: Supports platform reuse across multiple cell lines and Transwell formats due to low-cost, customizable hardware design.
Translational & Preclinical Research
- Translational Continuity: Bridges discovery and preclinical stages by providing disease-relevant barrier metrics predictive of in vivo permeability and tissue integrity.
- Risk-Adjusted Advancement: Supports go/no-go decisions by identifying compounds that disrupt barrier function early in the pipeline.
- Biomarker Alignment: Enables correlation of TEER changes with translational biomarkers of epithelial health and tight junction modulation.
Pipeline & Workflow Integration
The method integrates into the discovery continuum from early target validation through lead identification to preclinical barrier assessment, enabling data-driven progression based on functional epithelial integrity.
- Discovery Biology: Supports hypothesis testing and pathway clarification by linking genetic or pharmacological interventions to measurable changes in epithelial impedance.
- Screening: Delivers assay readiness and quantitative impedance outputs that allow reliable comparison of test conditions across compound libraries.
- Analytics: Provides precise resistance measurements (0–1.8 kΩ range) and frequency-programmable signals that support statistical comparison and data normalization.
- Translational Research: Connects to preclinical continuity by modeling human barrier systems (e.g., blood-cerebrospinal fluid) with validated cell lines.
- Enterprise Reuse: Represents a reusable, low-cost capability for barrier function assessment across multiple projects and therapeutic areas.
Operational & Enterprise Impact
- Scientific Value: Enhances predictive confidence in target validation by reducing mechanistic ambiguity in barrier-related mechanisms.
- Operational Value: Ensures standardization and reproducibility through programmable frequency control and four-terminal sensing architecture.
- Strategic Value: Improves capital efficiency by enabling in-house assembly of reliable TEER systems, reducing dependency on expensive commercial devices.
- Portfolio Impact: Informs risk-adjusted prioritization by identifying barrier-disrupting liabilities early, mitigating late-stage attrition risks.
Implementation Considerations
- Requires basic electronics expertise for assembly, including soldering, crimping, and continuity testing of custom cables and connectors.
- Depends on access to a USB development board, 8-bit microcontroller, standard multimeters with TrueRMS microampere capability, and a 120 kΩ resistor for current limiting.
- Necessitates cross-team standardization of electrode preparation, medium equilibration, and measurement timing to ensure reproducible results.
- Requires adaptation of chopstick electrode positioning and stabilization techniques when applied to different Transwell pore sizes or cell monolayer thicknesses.
- Limited to impedance measurements within the 0–1.8 kΩ range; higher resistance systems may require adjustments to current-limiting resistor or amplifier gain.
Biopharma FAQs
Why does programmable output frequency matter for TEER-based target validation?
Programmable output frequency allows optimization of impedance measurements across different cell models and barrier types, reducing measurement artifacts and improving data reliability in target validation workflows.
How does isolating current and voltage electrodes improve TEER measurement accuracy?
Four-terminal sensing uses separate electrode pairs for current delivery and voltage sensing, minimizing errors from electrode polarization and contact impedance, which enhances precision in barrier function assessment.
What quantitative TEER outputs enable compound screening decisions?
Stable impedance readings in ohms, derived from voltage and current measurements via Ohm’s Law, provide quantitative thresholds for assessing compound effects on epithelial integrity and permeability.
Why are replication requirements important for TEER data in cross-functional collaboration?
Replication ensures measurement consistency across users, labs, and timepoints, supporting reliable data sharing between discovery, screening, and preclinical teams for aligned go/no-go decisions.
What statistical analysis is needed before implementing TEER in a discovery pipeline?
Baseline variability, signal-to-noise ratio, and dose-response reproducibility must be established using control and reference compounds to define meaningful thresholds for hit selection and lead optimization.
