SomaScan | SomaLogic
At CITOGEN we perform proteomic analyses using SomaLogic technology. The SomaScan ® assay is the first and only platform that can measure 11k proteins from a minimum sample volume.
This accounts for more than twice the amount of proteins than any other proteomic analysis platform, thus covering a higher number of biological pathways as compared to any other proteomic assay that is available.
The SomaScan® assay uses modified aptamers (SOMAmer®) to provide 11k highly reproducible circulating protein measurements from a single plasma, serum or urine sample.
11K PROTEINS
50 µL SAMPLE
REPRODUCIBLE
(~5% CV)
SPECIFIC
DYNAMIC
10-log (fM to uM)
SENSITIVE
What are SOMAmer®?
SOMAmer® (Slow Off-Rate Modified Aptamers) are chemically modified nucleotide protein capture reagents that improve the specificity and affinity of protein-nucleic acid interactions as compared to standard aptamers and antibodies.
- Single reagents: Single-stranded synthetic oligonucleotides capable of specifically recognising high-affinity target proteins.
- Stable and quantifiable
- For discovery, validation and development: Unlike antibodies, SOMAmer® reagents are consistent, allowing for unmatched reproducibility.
- Selected by SELEX: This method allows one to select the oligonucleotide from the gene library that binds with the highest affinity to the target proteins based on its shape and charge complementarity. Through a process of iterative rounds of amplification and selection, aptamers with better binding and capture properties, comparable to that of antibodies, are selected.
What can it be used for?
How does it work?
SOMAmer® reagents are incubated with the sample, resulting in the formation of highly specific complexes of the SOMAmer® and the proteins. Each SOMAmer® is subsequently released from its target protein and subjected to competition with polyanionic molecules in order to prevent non-specific binding. Because SOMAmer® have a low dissociation constant, proteins remain bound to them. Fluorophores are measured after hybridisation with complementary sequences on a microarray chip. The fluorescence intensity detected in the microarray is related to the number of epitopes available in the original sample.
SOMAmer reagents (purple) are synthesised with a fluorophore, a photolabile link and biotin.
SOMAmer reagents bound to streptavidin beads are used to capture proteins from a complex mixture of proteins (brown).
Proteins that have not been bound are washed away, and the bound proteins are labelled with biotin.
Ultraviolet light breaks the photolabile link, releasing the complexes back into the solution.
Non-specific complexes dissociate while specific complexes remain bound.
A polyanionic competitor (green) prevents re-incorporation of non-specific complexes.
Biotinylated proteins (and bound SOMAmer reagents) are captured on new streptavidin beads.
When the SOMAmer reagents are released, they are hybridised to complementary sequences on a microarray chip and fluorescence intensity is subsequently measured, which is related to the amount of epitope available in the original sample.
Learn how the SomaScan ® assay works
What is the process?
Explore the 11K SomaScan menu
Key aspects
Reproducible
SomaScan data achieves very low variation coefficients (~5% CV) because the SomaScan assay is not based on polyclonal antibodies, which are variable. In addition, it is the only platform that can be used for biomarker research from discovery to development consistently over time.
Specific
While most protein assays are based on a variation of the ELISA sandwich technique, the SomaScan assay is based on kinetics: non-specific interactions dissociate faster. Tests have confirmed minimal cross-reactivity with closely related proteins.
Sensitive and dynamic
Serial dilutions are used to measure very high and very low abundance proteins separately, so that a total range of 10 logarithms can be measured from only 55 μl of plasma or serum.
| Protein levels | fM-pM | nM | uM |
| Plasma dilution | 1:5 | 1:200 | 1:20000 |
| Somamers | 81% | 16% | 3% |
11k proteins
The largest commercial proteomic assay on the market, providing more than 11k unique protein measurements.
Publications
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