Radiometric imaging beads – Scintillation Proximity Assay (SPA)

Microscopic beads contain a scintillant that can be stimulated to emit light. This stimulation event only occurs when radiolabeled molecules of interest are bound to the surface of the bead then blue light is emitted that can be detected on standard scintillation counters.

Please use the selection guide below to determine the best product for your needs:



About the technology:

• Red-shifted: Reduces incidence of color quenching.
• Homogeneous: No separation or washing steps required. Simply mix and measure.
• Versatile: A range of bead coatings allow a variety of targets to be assayed, from receptor binding to molecular interactions.
• Reduced assay costs: Eliminates requirement for filters and scintillation cocktails.
• Reduced disposal costs: No radioactive liquid waste from filtration steps.
• Improved safety: Reduced assay steps means less handling.
• Precise: No separation steps reduce potential error.
• Convenient: Pre-coated; quantity per assay can be optimized.
• Automatable: compatible with 96-, 384-, and 1536-well formats.

Technology in depth
The red-shifted SPA Imaging Beads emit at 615 nm and are optimum for the CCD chip that is most sensitive to light from the red region of the spectrum. Many candidate compounds are naturally colored (typically yellow and brown) and absorb light from the blue region of the emission spectrum. Using SPA Imaging Beads, potential color quench issues are overcome.

Choosing a bead
Available as two core bead types, polystyrene (PS) and yttrium oxide (YOx) for optimum choice in assay design. PS allows ease of handling and is especially suited to automation and higher throughput while YOx offers additional scintillation counting efficiency and enhanced sensitivity.

Learn more about the LEADseeker Imaging System, begin with an introduction

Find out how to interpret your complex, screening data - visit the software and informatics pages.

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View the fluorescence application data pages to see some sample assays you can perform

Consult our literature section for a comprehensive overview of application notes, posters, user manuals, articles and brochures