As demonstrated by the introduction of novel mass spectrometry (MS) methods that add further dimensions to traditional MS, many next generation proteomics approaches aren’t attempting to reinvent the wheel. Rather, these new technologies build off and expand upon existing ones, including a new class of multiplex immunoassays that improve on the sensitivity or multiplexing abilities of conventional immunoassays like ELISA.
A typical multiplex immunoassay workflow involves binding proteins in a sample with labeled microparticles or beads (magnetic or otherwise), applying fluorescence, and amplifying the product in microwells or suspension bead arrays for imaging and digital detection. Most of the assays can detect up to ten targets, while Luminex’s xMAP technology enables detection of up to 500 proteins and is the most prevalent N-plex ELISA platform on the market. These assays are well established, accessible, and efficient, and are often applied to clinical biomarker discovery and research. Over the next five years, the market for N-plex ELISA products is projected to nearly double.
For certain applications, an even higher plex is desired, and an approach known as affinity-based detection can be useful in these scenarios. Similar to DNA microarrays, these methods identify and measure proteins in a low-concentration sample with oligonucleotide-tagged antibodies. Olink, a proteomics company established in 2004 and headquartered in Uppsala, Sweden, is a dominant player in this area with a leading product based on patented technology. Olink’s Proximity Extension Assay (PEA) combines antibody binding and DNA hybridization to quantify as many as 1,100 proteins, depending on the panels used. Results are read out by either real-time PCR or next-generation sequencing. In addition to the achievement of an elevated plex, these assays are capable of analyzing low-concentration samples and require low sample volume, making them well suited for clinical research when sample availability is limited (for example, Olink’s PEA requires just 1 microliter when analyzing via PCR). Affinity-based detection is an emerging technique in the next-gen proteomics market beginning to build value and is expected to grow by at least an order of magnitude in the next five years.
Two further next-generation proteomics approaches are spatial profiling and single cell proteomics. Part of the larger field of spatial biology (the study of biological systems in their two- or three-dimensional contexts), spatial profiling uses antibody detection to locate cell types in tissue. These methods seek to interrogate proteins and their interactions deeply in situ, often for the purposes of biomarker discovery, tumor microenvironment characterization, and study of therapeutic targets and disease response. Single cell proteomics employs technologies like MS and mass cytometry at the single cell rather than population level.
Massachusetts-based Akoya Biosciences is leading the spatial biology charge with its PhenoCycler instrument and paired imaging platform, which allow users to automate staining and detection of as many as 100 biomarkers in tissue samples (the system boasts the ability to map 1 million cells in 10 minutes). On the single cell-side, Standard BioTools, formerly known as Fluidigm, is the exclusive provider of CyTof mass cytometry technology, which labels antibodies with metallic tags for time-of-flight MS readout of proteins in single cells. Across vendors, clinical research (especially oncology) and drug discovery are major applications of spatial and single-cell approaches, and biopharma is expected to account for two-thirds of demand for these techniques and products in 2027, by which time the market will have more than doubled.