title: A DNA-mediated homogeneous binding assay for proteins and small molecules.
abstract: Optical detection of molecular targets typically requires immobilization, separation, or chemical or enzymatic processing. An important exception is aptamers that allow optical detection in solution based on conformational changes. This method, however, requires the laborious selection of aptamers with high target specificity and affinity, and the ability to undergo the required conformational changes. Here we report on an alternative generic scheme for detecting small molecules and proteins in solution based on a shift in the equilibrium of DNA-based strand displacement competition reaction. The shift occurs upon binding of a protein, for example, an antibody to its target. We demonstrate nanomolar detection of small molecules such as biotin, digoxigenin, vitamin D, and folate, in buffer and in plasma. The method is flexible, and we also show nanomolar detection of the respective antibodies or protein targets of these molecules. The detection scheme provides a generic alternative to aptamers for detection of analytes.
authors: Center for DNA Nanotechnology (CDNA) at the Interdisciplinary Nanoscience Center (iNANO), Aarhus University , DK-8000 Aarhus C, Denmark.
authors: Zhao
authors: Z
authors: Zhang
authors: Christian
authors: C
authors: Hejesen
authors: Michael B
authors: MB
authors: Kjelstrup
authors: Victoria
authors: V
authors: Birkedal
authors: Kurt V
authors: KV
authors: Gothelf
mesh_terms: D001667:Binding, Competitive; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000032:analysis; D001774:Blood Chemical Analysis; D004247:DNA / Q000378:metabolism*; D004563:Electrochemistry; D031541:Fluorescence Resonance Energy Transfer; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D012463:Saliva / Q000737:chemistry; D019809:Streptavidin / Q000032:analysis
chemical_list: D011506:Proteins; D001710:Biotin; D004247:DNA; D019809:Streptavidin