TEER measurement device with automatic data logging

Features

• Low noise design offers greater resolution and accuracy in your TEER measurement protocol
• Automatic 20X sample averaging improves accuracy and stability
• Adjustable fixed measurement currents (2, 4 or 10 μA)
• Resistance auto ranging from 1 Ω to 100,000 Ω or with three fixed current ranges
• Reliable low current, low voltage design prevents metal ion transport
• Fast resistance stabilization on low levels under 200 Ω with resolution to 0.1 Ω
• Ergonomic tilt stand for low glare operation
• Graphical display of popular plates (6, 12, 24, 96) for trend analysis
• Display shows the most recent set of parameters
• Automatic plate indexing operation with or without control well subtraction for resistance and potential difference (PD) measurements
• Continuous data logging via USB (PC, Mac, Linux)
• Saves date stamped data to a spreadsheet readable file on a USB drive
• Upgradable firmware
• Upgrade of the EVOM3, in the trusted family of the EVOM™ brand of TEER measurement products

Benefits of the EVOM™ Manual TEER Measurement Device

• Eliminates errors and reduces experimental processing time
• Auto data logging eliminates the need to track data by hand
• The small footprint allows more bench space
• Easy calibration and verification
• Footswitch for hands-free recording
• Prevent data loss with auto save and data recovery when battery is low
• Easy TEER value calculation by applying a unit area formula to the resistance
• Premium Warranty Available

Applications for TEER Assays

• Measure epithelial or endothelial tissues for confluence, TEER and potential difference
• Permeability, conductance and drug studies
• Continuous digital monitoring of a target membrane
• Common studies
• Blood-brain barrier transport
• Lung epithelial tissue studies
• Intestinal tissue studies
• Skin studies

EVOM™ Manual For TEER Measurement

The EVOM™ Manual delivers improved workflow efficiency, more stable and repeatable measurements versus traditional Trans Epithelial Electrical Resistance (TEER) meters. Providing you with vital feedback during experiment measurements, the EVOM™ Manual’s large screen offers a range of informational views. The new graphical displays for trend analysis and measurement values helps scientists deliver simple, stepwise methodology during experimental measurements. The touch screen interface provides you with an intuitive, easy-to-use menu for configuration.

Eliminating the need to log data by hand, the EVOM™ Manual writes the resistance or voltage information to a USB drive in CSV format for easy transfer to spreadsheets and data analysis programs. When used with the footswitch it enables hands-free recording of measurements.

At the heart of the EVOM™ Manual is our latest processor and circuitry, providing users with quick, easy and reliable readings due to its fast stabilization, automatic twenty times sampling average and low noise design. The auto ranging resistance feature allows for fast resistance measurements, and an over-range display feature eliminates false readings. The EVOM™ Manual has adjustable current levels in three fixed ranges with two lower ranges for sensitive membranes and high resistance ranges up to 100 KΩ.

How Does the EVOM™ Manual Work?

Confluence of a cellular monolayer is determined by an increase or a plateau in tissue resistance detected using the unique electronic circuit of the EVOM™ Manual and the new STX4 electrode. The EVOM™ Manual qualitatively measures cell monolayer health and quantitatively measures cell confluence. The EVOM™ Manual produces a low AC current that avoids electrode metal deposits and adverse effects on tissues which can otherwise be caused by higher DC currents. The EVOM™ Manual uses low current and voltages and is designed for non-destructive testing for epithelial monolayer confluence in cell cultures. In addition, resistance readings are unaffected by membrane capacitance or membrane voltage. The accuracy and repeatability of the EVOM™ Manual-STX4 system makes this instrument ideal for permeability, PD and other detailed membrane studies.

Electrodes For TEER (Epithelial) Measurement

*(Requires 99672 for use with the EVOM3 or EVOM™ Manual)

ENDOHM Chambers For Endothelial/Epithelial Measurement

NEW EndOhm chambers include the EVOM™ Manual cable 99916.

TEER measurement techniques for in vitro barrier model systems

EVOM™ TEER Measurement Basic Working Principle

What is TEER?

TEER, Trans Epithelial Electrical Resistance, monitures the electical resistance of a cellular layer is the inverse presentation of the electrical conductance through the cellular layer. A high TEER value of the cellular layer is indicative of an intact cellular monolayer and suggests low or restricted permeability of ions and molecules (i.e., low conductance). Similarly, a decrease in the TEER value suggests a compromised barrier function and indicates increased permeability. Tissue permeability studies require a confluent cellular layer, and TEER measurement is gennerally used to confirm the formation of a confluent monolayer.

Initially, 24 hours after cell seeding transwell, TEER values are generally low, because the current passes can pass easily between the cells. Over time, the cells multiply and start covering the gaps. Finally, a confluent cellular monolayer is formed. At that point the permeable membrane is fully covered with cells and does not allow easy passage of electrical current. This results in a high TEER value.

TEER Value Calculation

TEER is a normalized value of resistance per 1 square centimeter of unit area. To compute TEER, multiply the measured resistance by the surface area listed below.

For example, a 6.6 mm insert measures 1707 Ω, the TEER is 1707 Ω * 0.331 or 505 Ω.

• 6 well plate (24 mm inserts) 4.53 cm²

• 12 well plate (12 mm inserts) 1.13 cm²

• 24 well plate (6.5 mm inserts) 0.3316 cm²

• 96 well plate (4.3 mm inserts) 0.145 cm²