METHODS FOR DETECTION OF AN ANALYTE BY MOVEMENT OF TETHERED MICROPARTICLES

摘要

An immune sandwich assay in which read-out is based on counting micron-size beads tethered by polymeric molecules (such as nucleic acid) is described. The motion of tethered beads in flow is recognizable with a low-power optical microscope and distinguishable from that of beads that stick non-specifically to the flow cell surface. Analyte molecules are captured efficiently by capture beads and labeled efficiently by labeled detection antibody. The assay disclosed herein is sensitive enough for the detection of single molecules and/or the detection of very low concentrations of analyte in a sample.