Liposome-enhanced test device and method
First Claim
1. A method for detecting or quantifying an analyte in a liquid test sample, comprising:
- providing a test device comprising;
a contact portion on a first absorbent material;
a capture portion either on said first absorbent material, or on a second absorbent material in fluid flow contact with said first absorbent material, wherein said capture portion has a first binding material bound to said capture portion; and
an electrode array comprising a first conductor having a plurality of fingers, and a second conductor having a plurality of fingers, wherein said fingers of said first conductor are interdigitated with said fingers of said second conductor, said first and second conductors are electrically connected to one another via a voltage source and readout device, and said array is positioned to induce redox cycling of an electroactive marker released in said capture portion;
applying the test sample to said contact portion;
applying a voltage across said conductors, wherein said potential is sufficient to induce redox cycling of said marker;
allowing the test sample to migrate from said contact portion into said capture portion;
contacting the test sample with a liposome conjugate of liposomes and a second binding material, wherein said liposomes encapsulate an electroactive marker, wherein said second binding material binds with a portion of the analyte; and
wherein said first binding material binds with a portion of the analyte other than the portion of the analyte for which the second binding material is selected;
incubating the test sample with the conjugate for a time sufficient to permit reaction between any analyte present in the test sample and the second binding material;
after said incubating and said allowing, lysing any liposomes present in said capture portion to release said marker, whereby said marker undergoes redox cycling induced by said conductors causing current to flow between said first and second conductors;
detecting the presence or amount of said current; and
correlating the presence or amount of said current with the presence or amount, respectively, of the analyte in the test sample.
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Accused Products
Abstract
A test device and method for detecting or quantifying an analyte in a test sample employs an interdigitated electrode array and electroactive marker-encapsulating liposomes for signal generation and detection. The test device includes a contact portion on a first absorbent material, a capture portion either on the first absorbent material, or on a second absorbent material in fluid flow contact with the first absorbent material. The capture portion has a binding material specific for a portion of the analyte bound thereto. The device further includes an electrode array including first and second conductors each having a plurality of fingers, wherein the fingers of the conductors are interdigitated. The electrode array is positioned to induce redox cycling of an electroactive marker released either in or beyond the capture portion, depending upon whether direct (proportional) or indirect (inversely proportional) detection or measurement is desired. In the method of the invention, the test sample is applied to the contact portion, and allowed to migrate along the absorbent material(s) into the capture portion. Either before or after the migration, the test sample is contacted with a conjugate of liposomes and a second binding material for the analyte. To the extent that analyte is present in the sample, the conjugate is bound in the capture portion. By applying a voltage across the conductors, redox cycling of the marker is induced and a current is generated.
121 Citations
28 Claims
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1. A method for detecting or quantifying an analyte in a liquid test sample, comprising:
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providing a test device comprising;
a contact portion on a first absorbent material;
a capture portion either on said first absorbent material, or on a second absorbent material in fluid flow contact with said first absorbent material, wherein said capture portion has a first binding material bound to said capture portion; and
an electrode array comprising a first conductor having a plurality of fingers, and a second conductor having a plurality of fingers, wherein said fingers of said first conductor are interdigitated with said fingers of said second conductor, said first and second conductors are electrically connected to one another via a voltage source and readout device, and said array is positioned to induce redox cycling of an electroactive marker released in said capture portion;
applying the test sample to said contact portion;
applying a voltage across said conductors, wherein said potential is sufficient to induce redox cycling of said marker;
allowing the test sample to migrate from said contact portion into said capture portion;
contacting the test sample with a liposome conjugate of liposomes and a second binding material, wherein said liposomes encapsulate an electroactive marker, wherein said second binding material binds with a portion of the analyte; and
wherein said first binding material binds with a portion of the analyte other than the portion of the analyte for which the second binding material is selected;
incubating the test sample with the conjugate for a time sufficient to permit reaction between any analyte present in the test sample and the second binding material;
after said incubating and said allowing, lysing any liposomes present in said capture portion to release said marker, whereby said marker undergoes redox cycling induced by said conductors causing current to flow between said first and second conductors;
detecting the presence or amount of said current; and
correlating the presence or amount of said current with the presence or amount, respectively, of the analyte in the test sample. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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2. A method for detecting or quantifying an analyte in a liquid test sample, comprising:
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providing a test device comprising;
a contact portion on a first absorbent material;
a capture portion either on said first absorbent material, or on a second absorbent material in fluid flow contact with said first absorbent material, wherein said capture portion has a first binding material bound to said capture portion; and
an electrode array comprising a first conductor having a plurality of fingers, and a second conductor having a plurality of fingers, wherein said fingers of said first conductor are interdigitated with said fingers of said second conductor, said first and second conductors are electrically connected to one another via a voltage source and readout device, and said array is positioned to induce redox cycling of an electroactive marker released from liposomes which migrate beyond said capture portion;
applying the test sample to said contact portion;
applying a voltage across said conductors, wherein said potential is sufficient to induce redox cycling of said marker;
allowing the test sample to migrate from said contact portion through said capture portion;
contacting the test sample with a liposome conjugate of liposomes and a second binding material, wherein said liposomes encapsulate an electroactive marker, wherein said second binding material binds with a portion of the analyte; and
wherein said first binding material binds with a portion of the analyte other than the portion of said analyte for which said second binding material is selected;
incubating the test sample with the conjugate for a time sufficient to permit reaction between any analyte present in the test sample and the second binding material;
after said incubating and said allowing, lysing any liposomes which migrate beyond said capture portion to release said marker, whereby said marker undergoes redox cycling induced by said conductors causing current to flow between said first and second conductors;
detecting the presence or amount of said current; and
correlating the presence or amount of said current with the presence or amount, respectively, of the analyte in the test sample, wherein the presence or amount of said current is inversely proportional to the presence or amount, respectively, of the analyte in the test sample.
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20. A test device for detecting or quantifying an analyte in a liquid test sample, said test device comprising:
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a contact portion on a first absorbent material;
a capture portion either on said first absorbent material, or on a second absorbent material in fluid flow contact with said first absorbent material, wherein said capture portion has a binding material specific for the analyte bound to said capture portion; and
an electrode array comprising a first conductor having a plurality of fingers, and a second conductor having a plurality of fingers, wherein said fingers of said first conductor are interdigitated with said fingers of said second conductor, and wherein said electrode array is positioned to induce redox cycling of an electroactive marker released in said capture portion. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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21. A test device for detecting or quantifying an analyte in a liquid test sample, said test device comprising:
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a contact portion on a first absorbent material;
a capture portion either on said first absorbent material, or on a second absorbent material in fluid flow contact with said first absorbent material, wherein said capture portion has a binding material specific for the analyte bound to said capture portion; and
an electrode array comprising a first conductor having a plurality of fingers, and a second conductor having a plurality of fingers, wherein said fingers of said first conductor are interdigitated with said fingers of said second conductor, and wherein said electrode array is positioned to induce redox cycling of an electroactive marker released from liposomes which migrate out of said capture portion.
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Specification