Very low limits of detection (300 fM median), 7 logs of overall dynamic range, and 5% average coefficient of variation 1,2. This technology is enabled by a new generation of aptamers that contain chemically modified nucleotides, which greatly expand the physicochemical diversity of the large randomized nucleic acid libraries from which the aptamers are selected. Proteins in complex matrices such as plasma and serum are measured with a process that transforms a signature of protein concentrations into a corresponding DNA aptamer concentration signature, which is then quantified with a DNA microarray. In essence, this assay takes advantage of the dual nature of aptamers as both folded binding entities with defined shapes and unique sequences recognizable by specific complementary hybridization probes (see Figure 1). For more than two decades, there has been growing interest in proteomic biomarker screening technologies1,3. Though several technologies have been applied to this effort with some limitations4,5, recent work by SomaLogic has demonstrated the use of slow off-rate modified aptamer (SOMAmer reagents to enable multiplexed screening of thousands of serum or plasma proteins.87081-35-4 MedChemExpress Using the SOMAscanTM assay, we are able to measure 1000 proteins and are working towards a 3000-plex.300586-90-7 SMILES The use of the photocleavable biotin (PCB) reagent6,7 as a capture/release agent in our assay (see Figure 1) has enabled assay development and implementation for the use of these highly specific and diverse set of reagents.PMID:30725886 Integration of the PCB reagent and a suitable fluorophore (i.e. cyanine-3) onto the termini of SOMAmer reagents with suitable
FIGURE 1: MULTIPLEXED SOMAmer AFFINITY ASSAY
(a) SOMAmers labeled with a fluorophore (F), photocleavable linker (L), and biotin (B) are immobilized on streptavidin (SA)-coated beads and incubated with samples containing a complex mixure of proteins (e.g., plasma).
(e) Incubation in a buffer containing a polyanionic competitor selectively disrupts nonspecific interactions.
modified nucleotide positions2,8,9 (see Figure 2, Page 8) affords these measurements through binding of cognate proteins and subsequent quantification on a DNA microarray. Further work is underway to expand content and implement the larger 3000-plex with appropriate assay improvements and validation.
1) Gold et al, (2010), Aptamer-based multiplexed proteomic technology for biomarker discovery, Nature Precedings 2) Rohloff et al, (2014), Nucleic Acid Ligands With Protein-like Side Chains: Modified Aptamers and Their Use as Diagnostic and Therapeutic Agents, Molecular Therapy Nucleic Acid, 3, e201 3) Zichi, D. et al, (2008), Proteomics and diagnostics: Let’s get specific, again. Curr. Opin. Chem. Biol. 12, 78-85 4) Knezevic et al, (2001), Proteomic profiling of the cancer microenvironment by antibody arrays, Proteomics, 1, 1271278 5) Gregorich and Ge,(2014), Top-down proteomics in health and disease: Challenges and opportunities, Proteomics, 14, 1195210 6) Olejnik et al, (1996), Photocleavable biotin phosphoramidite for 5′-end-labeling, affinity purification and phosphorylation of synthetic oligonucleotides, Nucleic Acids Research, 24:2, 361-366 7) Olejnik et al, (1999), Photocleavable peptide-DNA conjugates: synthesis and applications to DNA analysis using MALDIMS, Nucleic Acids Research, 27:33, 46264631 8) Vaught, J. D. et al, (2010), Expanding the chemistry of DNA for in vitro selection, J. Am. Chem. Soc. 132, 4141-4151 9) Rohloff et al, (2015), Practica.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
