Magnetic immunosensor with trench configuration and method of use
Inventors
Campbell, John Lewis Emerson • Miller, Cary James
Assignees
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Publication Number
US-11402375-B2
Publication Date
2022-08-02
Expiration Date
Abstract
The present invention provides apparatus and methods for the rapid determination of analytes in liquid samples by immunoassays incorporating magnetic capture of beads on a sensor capable of being used in the point-of-care diagnostic field.
Core Innovation
The invention relates to a point-of-care magnetic immunosensing device that integrates a cartridge housing with a sample inlet, a sample chamber, a conduit, and a sensor chip located within the conduit. The sensor chip is formed on the base of the cartridge housing and includes a single sensing electrode comprising a silicon wafer with a single trench, an insulating oxide layer, metal layers, and a photodefinable polyimide with electrode openings that expose portions of the metal layers. The electrode openings form a two-dimensional array of microfabricated electrodes at the bottom of the single trench, including a line of microelectrodes in the trench.
A dissolvable dry matrix comprising magnetically susceptible beads is located in the sample chamber or the conduit and is configured to dissolve in the sample fluid. The device includes a permanent high-field magnet formed in the base abutting a bottom of the sensor chip, configured for retaining at least a portion of the beads in the trench. A pump moves the sample from the sample chamber through the conduit to the sensing electrode, enabling localized bead presence at the microfabricated electrode structure during measurement.
The approach emphasizes retaining localized beads in a trench configuration during wash-related fluid handling using the permanent high-field magnet, supporting magnetic capture and retention. The system is described as providing device and assay embodiments including sandwich and competitive immunoassay formats, with dissolvable dry reagent handling such that bead-based immune sensing is performed in a localized sensing region. The document further discusses assay approaches including hybrid overlapping-range sensing and oscillating-bead immunoassay (OBIA) and multiplexing, including reference immunosensor embodiments.
Claims Coverage
The independent claim identified in the provided material is clm-00001. It contains one independent set of inventive features centered on a cartridge-based point-of-care magnetic immunosensing architecture that localizes a dissolvable bead matrix within a single-trench microfabricated electrode using a permanent high-field magnet, while sample is moved by a pump to the sensing electrode.
Cartridge-based microfabricated single-trench sensing electrode
A cartridge housing comprising a base; a sample chamber comprising a sample inlet for receiving a sample; a conduit in fluidic communication with the sample chamber; and a sensor chip located within the conduit and formed on the base of the cartridge housing, wherein the sensor chip comprises a single sensing electrode comprising a silicon wafer with a single trench, an insulating oxide layer, metal layers on the insulating oxide layer, a photodefinable polyimide formed on the metal layers, and electrode openings formed into the photodefinable polyimide exposing portions of the metal layers to form a two-dimensional array of microfabricated electrodes at a bottom of a single trench, wherein the two-dimensional array comprises a line of microelectrodes in the single trench.
Dissolvable dry matrix of magnetically susceptible beads
A dissolvable dry matrix comprising magnetically susceptible beads, wherein the matrix is configured to dissolve in the sample fluid and wherein the dissolvable dry matrix is located in the sample chamber or the conduit.
Permanent high-field magnet for retaining beads in the trench
A permanent high-field magnet for retaining at least a portion of said beads in said trench, wherein the permanent high-field magnet is formed in the base abutting a bottom of the sensor chip.
Pump-driven sample movement through the conduit to the sensing electrode
A pump for moving the sample from the sample chamber through the conduit to the sensing electrode.
Across the provided independent claim, the core claim coverage centers on a point-of-care cartridge with a microfabricated single-trench, two-dimensional microelectrode array sensor, a dissolvable dry bead matrix in the cartridge fluid path, and a permanent high-field magnet formed in the cartridge base to retain the beads in the trench as the pump moves sample through the conduit to the sensing electrode.
Stated Advantages
Not explicitly described in patent.
Documented Applications
cTnI detection using a cartridge-based magnetic immunosensing assay with performance described for rapid assay timing and retention performance during washing [procedural detail omitted for safety].
Reference immunosensor embodiments including sandwich and competitive immunoassay formats for immunosensing [procedural detail omitted for safety].
Oscillating-bead immunoassay (OBIA) approaches and multiplexing described for overlapping-range sensing and multiplexed OBIA sensing.
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