• Proximity Extension Assay (PEA) technology

    Innovation for successful protein biomarker discoveryPEA icon

    The unique technology behind our biomarker panels enables high-throughput, multiplex immunoassays that measure 92 proteins across 96 samples simultaneously using only one microliter of serum, plasma, or almost any other type of biological sample. Here we will show you how our technology delivers this scale of multiplexing and sample throughput without compromising on data quality or assay robustness.

    Olink’s PEA technology – the movie

    The short video below overviews the Proximity Extension Assay (PEA) technology that lies behind our 92-plex immunoassay panels for human protein biomarker research. The animation explains how our innovative dual recognition, DNA-coupled methodology provides exceptional readout specificity, enabling high multiplex, rapid throughput biomarker analysis without compromising on data quality.

    Note: If you are unable to view the video in full-screen mode your browser, please go direct to our YouTube channel instead

    Olink assay overview

    The main steps involved in an assay are outlined below. A pair of oligonucleotide-labeled antibodies, Proseek probes, are allowed to pair-wise bind to the target protein present in the sample in a homogeneous assay, with no need for washing. When the two Proseek probes are in close proximity, a new PCR target sequence is formed by a proximity-dependent DNA polymerization event. The resulting sequence is subsequently detected and quantified using standard real-time PCR.

    PEA1

    Each of the 96 oligonucleotide antibody-pairs contains unique DNA sequences allowing hybridization only to each other. Subsequent proximity extension will create 96 unique DNA reporter sequences which are amplified by real-time PCR. A limiting factor of multiplexed immunoassays is the antibody cross-reactivity which restricts the degree of multiplexing of most assays to below 10-plex. Cross-reactive events will not be detected with Olink’s panels since only matched DNA reporter pairs are amplified with real-time PCR, see figures below. This allows for scalable multiplexing without loss of specificity and sensitivity.

    PEA2a-v2

    A) Conventional immunoassays: cross-reactivity due to unspecific binding of antibodies limits the degree of multiplexing.

    PEA2b-v2

    B) Olink’s technology: unique DNA oligo sequences report only matched DNA-pairs (e.g. 1A+1B). Cross-reactive events are not detected.