Immunomagnetic DNA aptamer assay

DNA aptamers, oligonucleotides with antibody-like binding properties, are e asy to manufacture and modify. As a class of molecules, they represent the biggest revolution to immunodiagnositcs since the discovery of monoclonal a ntibodies. 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 an tithrombin antibody (EST-7). Our results show that the thrombin DNA aptamer is capable of binding to its target molecule under stringent in vitro assa y conditions and at physiological concentrations. These findings also suppo rt the view that DNA aptamers have potential value as complementary reagent s in diagnostic assays.