Nanopore detection of small molecules through competition assays

Abstract

Disclosed herein are methods and compositions for detection of target small molecules in a mixed sample by performing a competition assay between the target and a surrogate and subsequently detecting the complex types in a nanopore device. Disclosed herein are competition assays for detection of small molecules using a nanopore. Target molecules of a sufficient size (>20 kDa) when passed through a solid-state nanopore cause a change in the current impedance, translocation time, or other measurable parameter. In the event the target molecule is not sufficiently big, and thus does not cause a noticeable change, an additional molecule/reagent can be used to aid in detection. This detection reagent would bind to the small molecule or to the 'capture ligand-molecule complex' (e.g. peptide detection is aided by a monoclonal antibody (mAb) that recognizes a peptide/aptamer complex).