Converting an ELISA Assay into an Octet® BLI Quantitation Assay


Enzyme-linked immunosorbent assays (ELISA) are routinely used to quantitate molecules and despite their popularity, these assays are labor- and time-intensive. Quantitation assays on the Octet® platform can be considered automated forms of ELISA but allow a myriad of benefits compared to standard ELISA assays, notably the ability to detect lower affinity interactions and a reduced hands-on time for the scientist. As with ELISA, the signal reported in quantitation assays is either directly or inversely proportional to the amount of bound analyte.

The conversion of many existing ELISA to an Octet® assay typically requires simple re-optimization and validation of the conditions and configurations. This application note describes the key steps for ensuring successful conversion of an ELISA-based assay to the Octet®, including defining the assay requirements, selecting the biosensor type and assay format, minimizing non-specific binding, and
optimizing the assay buffer.

It is often beneficial to convert ELISA assays to the Octet® platform as it allows the scientist to:

  1. Choose from a number of assay formats (label-free direct binding, sandwich, sandwich followed by signal amplification, etc.) to suit detection limit requirements
  2. Detect low-affinity analytes often missed by ELISA
  3. Minimize handling via automated and wash-free steps
  4. Fully recover and re-use samples and reagents
  5. Regenerate the assay surface and re-use for some binding pairs (e.g., Protein A/human IgG).


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