What is the STX HTS EVOM™ Electrode?

The STX HTS EVOM™ Electrode is World Precision Instruments' purpose-built solution for measuring transepithelial electrical resistance (TEER) on high-throughput screening (HTS) culture plates — the bonded, non-removable insert plates used widely in pharmaceutical and academic epithelial-transport research. Where automated TEER systems are out of reach, the STX HTS lets you measure the same HTS plates manually with a hand-held electrode at a fraction of the cost.

Each STX HTS variant is engineered to self-align on a specific manufacturer's HTS plate format. The result is the spatial repeatability that automated systems are prized for — without the operator-induced variability that plagues handheld "chopstick" electrodes like the STX2 in HTS workflows. WPI offers five variants covering the four leading HTS plate ecosystems: Corning 24-well, Corning 96-well, Corning Falcon 24-well, Millipore 96-well, and MatTek 96-well.

Key Features

• HTS plate-specific design: Each electrode self-aligns to one manufacturer's apical and basal access ports, eliminating spatial variability between reads.
• Improved measurement accuracy: Resolves down to 5 Ω — enough to distinguish blank vs. confluent monolayers in tight-resistance ranges.
• Smaller, more durable tip than STX2: Fits the keyhole-shaped wells of HTS filter plates and stands up to repeated use.
• Reduced contamination risk: Geometry minimizes contact with surrounding wells; sterilizable with EtO, alcohol, or bactericide.
• Broad meter compatibility: Works with the EVOM™ Manual directly, and with EVOM, EVOM2, Millicell® ERS, and ERS2 via the STX4 adapter cable (EVM-AC-02-01-01, sold separately).
• Cost-effective alternative to automation: Lets labs run validated manual TEER readings on the same HTS plates a fully automated system would use, at a fraction of the capital cost.

Choose the Right Variant for Your HTS Plate

Each manufacturer's HTS culture plate has a unique apical/basal port geometry, so the correct STX HTS EVOM™ Electrode is plate-specific. Pick the variant that matches the plate you actually run your assays on.

STX HTS vs. STX2 Chopstick — Why HTS-Specific Geometry Matters

Spatial orientation of the electrode during a TEER measurement has a significant effect on the resistance reading. The STX2 "chopstick" electrode is handheld and flexible, so two operators — or even the same operator on two different days — will produce different positional offsets, and that variability shows up in the data. The STX HTS solves this by self-aligning to the well geometry of the plate it was designed for, removing operator skill from the equation and producing reproducible readings well-to-well and plate-to-plate.

When to Choose Manual STX HTS vs. Automated EVOM™ Auto

If your throughput justifies it, WPI's EVOM™ Auto automates TEER reading across an entire 24- or 96-well HTS plate. The STX HTS is the right call when your study volume doesn't justify the capital cost of an automated reader, when you need a backup for a busy automated bench, or when you need the flexibility to read odd plate counts and partial-plate experiments by hand.

Sterilization & Care

The STX HTS is sterilizable with ethylene oxide (EtO), alcohol, or bactericide. Refer to the STX HTS Electrode Instruction Manual for full cleaning, storage, and sterilization protocols.