Immunomagnetic DNA Aptamer Assay

Abstract

DNA aptamers, oligonucleotides with antibody-like binding properties, are easy to manufacture and modify. As a class of molecules, they represent the biggest revolution to immunodiagnostics since the discovery of monoclonal antibodies. To demonstrate that DNA aptamers are versatile reagents for use as in vitro diagnostic tools, we developed a hybrid immunobead assay based on a 5'-biotinylated DNA thrombin aptamer (5'-GGTTGGTGTGGTTGG-3') and an anti-thrombin antibody (EST-7). Our results show that the thrombin DNA aptamer is capable of binding to its target molecule under stringent in vitro assay conditions and at physiological concentrations. These findings also support the view that DNA aptamers have potential value as complementary reagents in diagnostic assays.

A DNA aptamer population specifically detects Leishmania infantum H2A antigen

“…Aptamer-conjugated immunoassays using other platforms to detect specific proteins were reported earlier. 27,28 The most remarkable applications were the demonstration of a fiber-optic microarray biosensor using aptamers 29 and an aptamer-based quartz crystal biosensor. 30 None of these reports utilized nucleic acid-based enzymatic assays as described, consisting in an aptamer sandwich assay with digoxigenin-labeled aptamers in a 96-well microtiter plate format.…”

A new kind of aptamer-based immunomagnetic electrochemiluminescence assay for quantitative detection of protein

“…The innovative aspect of the aptamer-based IM-ECL assay is the coupling of aptamers with magnetic beads for the target protein immobilization before the ECL detection. Magnetic beads are a powerful tool in a variety of bioassays (Rye and Nustad, 2001). They can rapidly and simply select low-abundance target analytes (DNA, protein, bacteria) from complex samples without any pre-enrichment or purification steps.…”

Different approaches for the detection of thrombin by an electrochemical aptamer-based assay coupled to magnetic beads

“…The innovative aspect of all the proposed assays is the coupling of aptamers with magnetic beads for the aptamer or target immobilisation before the electrochemical transduction. Magnetic beads are known to be a powerful tool in a variety of bioassays (Rye and Nustad, 2001). Their use improves the performances of the affinity interaction for the faster assay kinetics achieved because the beads are in suspension and for the minimised matrix effect due to improved washing and separation.…”