Patent ID: 9678064
Date: 2017-06-13
CPC Classifications: B01L,G01N

Claim:
1. An assay apparatus comprising: an assay strip having a nanofluidic channel formed therein, said nanofluidic channel having a first tagging area with a plurality of magnetic particles releasably bonded thereto, said magnetic particles comprising a specific bonding substance that is chosen to bond to a substance of interest in a fluid, said magnetic particles having a predetermined size, said nanofluidic channel further having a sensing area comprising a plurality of magnetic particle traps configured and arranged to retain said magnetic particles therein, said sensing area being downstream of said first tagging area, said nanofluidic channel having a predetermined depth and configuration corresponding to said predetermined size of said magnetic particles whereby only a monolayer of magnetic particles in said fluid may flow through the entire nanofluidic channel; and an external magnetic field source adjacent to and outside of the sensing area, said fluid traveling along the nanofluidic channel in a monolayer from the tagging area to the sensing area where said magnetic particles become concentrated in the plurality of magnetic particle traps, said plurality of magnetic particle traps being spaced apart along a primary flow direction of said fluid through said sensing area, so that said plurality of magnetic particle traps define a series of ridges and troughs when viewed in a direction perpendicular to said primary flow direction of said fluid through said sensing area, and so that said plurality of magnetic particle traps are arranged in said nanofluidic channel to fill in sequence as said fluid progresses through said nanofluidic channel, said magnetic particles being sensed while trapped in said magnetic particle traps to provide an indication of the presence or absence of said substance of interest.