Binding assay with no wash steps or moving parts using magnetic beads
This present disclosure provides devices, systems, and methods for performing point-of-care analysis of a target analyte in a biological fluid via a binding assay. The present disclosure includes a cartridge for collecting the target analyte contained in a fluid sample and performing an assay. The cartridge includes an assay stack having a first separation layer, a second separation layer, and a detection membrane. The cartridge also includes a plurality of first complexes comprising a capture molecule and a magnetic bead and a plurality of second complexes comprising a detection molecule and a detection label. Further, the detection membrane includes a substrate that interacts with the detection label to elicit a quantifiable response in the presence of the target analyte. The quantifiable response corresponds to an amount of detection antibody present in the detection membrane, and the amount of detection antibody present corresponds to an amount of the target analyte present.
1 . A cartridge for collecting a target analyte contained in a fluid sample and performing an assay on the target analyte, wherein the cartridge comprises:
an assay stack, wherein the assay stack comprises:
a first separation layer;
a plurality of first complexes comprising a capture molecule and a magnetic bead;
a plurality of second complexes comprising a detection molecule and a detection label;
a second separation layer; and
a detection membrane comprising a substrate that interacts with the detection label to elicit a quantifiable response in the presence of the target analyte, wherein the quantifiable response corresponds to an amount of detection molecule present in the detection membrane, and wherein the amount of detection molecule present in the detection membrane corresponds to an amount of the target analyte present in the fluid sample; and
wherein the second separation layer prevents passage of any unbound second complexes of the plurality of second complexes to the detection membrane.
2 . The cartridge according to claim 1 , wherein the second separation layer comprises a hydrophobic membrane, a low molecular weight cut-off membrane, or a combination thereof that allows for a third complex comprising the target analyte bound to: (a) one of the first complexes and (b) one of the second complexes to pass to the detection membrane in the presence of an activated electromagnet.
3 . The cartridge according claim 1 , wherein the second separation layer includes a hydrophilic treatment.
4 . The cartridge according to claim 3 , wherein the hydrophilic treatment is a coating that comprises a surfactant.
5 . The cartridge according to claim 1 , wherein the target analyte is contained within a fluid sample selected from the group consisting of blood, saliva, sweat, urine, lymph, tears, synovial fluid, breast milk, serum, plasma, bile, or a component thereof.
6 . The cartridge according to claim 5 , wherein the fluid sample is blood and the first separation layer is a plasma separation membrane that prevents erythrocytes from contacting the second separation layer.
7 . The cartridge according to claim 1 , wherein the detection label comprises a peroxidase enzyme.
8 . The cartridge according to claim 7 , wherein the substrate comprises a reagent for the peroxidase enzyme.
9 . The cartridge according to claim 1 , wherein the cartridge is configured to perform an assay on the target analyte without any wash steps or moving parts.
10 . The cartridge according to claim 1 , wherein at least one component of the cartridge is compressible, thereby allowing for an uncompressed state and a compressed state of the cartridge.
11 . The cartridge according to claim 1 , further comprising a metering stack configured to receive and distribute the fluid sample containing the target analyte along a channel of the cartridge, wherein the channel has a bottom that comprises a porous or mesh material, further wherein the metering stack includes one or more venting holes in communication with the channel.
12 . The cartridge according to claim 11 , wherein a spacer material is disposed between the metering stack and the assay stack, wherein the spacer material provides a gap between the metering stack and the assay stack that prevents the target analyte from flowing from the metering stack into the assay stack when the cartridge is in the uncompressed state.
13 . The cartridge according to claim 11 , wherein the porous or mesh material permits the target analyte to flow from the metering stack to the assay stack upon compression of the at least one component of the cartridge.
14 . A system for collecting a target analyte contained in a fluid sample and performing an assay on the target analyte, the system comprising:
the cartridge of claim 1 ; and
an electromagnet for pulling a third complex comprising the target analyte bound to one of the first complexes and one of the second complexes through the second separation layer to the detection membrane.
15 . The system according to claim 14 , wherein the second separation layer allows for the third complex comprising the target analyte bound to: (a) one of the first complexes and (b) one of the second complexes to pass to the detection membrane when the electromagnet is activated.
16 . The system according to claim 14 , wherein the second separation layer prevents passage of any unbound second complexes to the detection membrane.
17 . The system according to claim 14 , wherein the system further comprises:
a metering stack configured to receive and distribute the target analyte along a channel of the cartridge, wherein the channel has a bottom that comprises a porous or mesh material and wherein the metering stack includes one or more venting holes in communication with the channel.
18 . The system according to claim 14 , further comprising an assay reader that includes the electromagnet.