Molecular Devices Launches No-Wash Potassium Ion Channel Assay Kit

Molecular Devices, at SLAS 2015, launched a homogeneous, no-wash assay to measure ligand- and voltage-gated potassium channel activity. The FLIPR® Potassium Assay Kit uses a novel thallium-sensitive indicator dye and a masking agent to significantly widen the conventional assay window, enabling studies of channels with low conductance or low expression levels. The kit's protocol eliminates the customary wash steps that introduce artificial variation and limit high-throughput automation.

Current thallium-based potassium ion channel assays require multiple buffer or media replacements, making them slow and cumbersome, and prone to well-to-well variation. Pervasive background noise also undermines accurate assessment of the small signals generated by many low-conductance channels or low-expressing cell lines.

The FLIPR Potassium Assay Kit directly measures potassium channel function using a thallium-sensitive indicator dye that passively diffuses into cells as an acetoxymethyl ester. Cytoplasmic esterases cleave the dye into its fluorogenic form. A proprietary masking agent further reduces the background fluorescence and enhances the signal-to-noise ratio. In a comparison to a commercial potassium assay, this kit increased the assay window several fold for many cell types. The no-wash format simplifies automation using 96-, 384-, and 1536-well formats in FLIPR and FlexStation microplate readers.

"The error bars are tighter with the new Molecular Devices kit, facilitating analysis of weakly expressed or weakly conducting potassium channels. The no-wash and no-buffer protocol disturbs cells less and speeds up automation," wrote one of the kit's beta testers, a principal scientist who leads pharmacology testing at one of the world's ten largest pharmaceutical companies.