Liposome-enhanced immunoaggregation assay and test device
First Claim
1. A method for detecting or quantifying an analyte in a test sample, comprising:
- providing a test device comprising an absorbent material, which absorbent material comprises;
a contact portion at or proximate to a first end of said absorbent material; and
an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end;
said electrochemical measurement portion comprising a working electrode portion, a reference electrode portion, and a counter electrode portion, wherein each of said electrode portions is segregated from one another on said absorbent material, said working, reference, and counter electrode portions are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said contact portion and said working electrode portion, wherein said liposome lysing portion is segregated from said contact portion and has a liposome lysing agent bound thereto, or said working electrode portion has a liposome lysing agent bound thereto;
combining a binding material specific for the analyte with a conjugate of an analyte analog and liposomes and the test sample in an electrolyte mixture, wherein said liposomes comprise an electroactive marker;
incubating the mixture for a time sufficient to permit competition between any analyte present in the test sample and the conjugate for the binding material;
contacting the mixture with said contact portion of said absorbent material after said incubating;
allowing the mixture to migrate from said contact portion through said electrochemical measurement portion of said absorbent material after said incubating, wherein migration of aggregates of conjugate and binding material formed during said incubating is inhibited by said absorbent material, whereby said liposomes are lysed by said liposome lysing agent to release said marker, and an electrical connection between said working, reference and counter electrode portions is established causing current to flow between said working and said counter electrode portions;
detecting the presence or amount of said current flowing between said working and said counter electrode portions; and
correlating the presence or amount of said current flowing between said working and said counter electrode portions with the presence or amount, respectively, of the analyte in the test sample.
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Accused Products
Abstract
A test device for detecting or quantifying an analyte in a test sample includes an absorbent material having separate contact and measurement portions. The contact portion is positioned at or proximate to a first end of the absorbent material. The measurement portion has a receptor for a conjugate of an analyte analog and marker-encapsulating liposomes. In a method for using the test device, a binding material specific for the analyte is combined with the liposome-analyte analog conjugate and the test sample to form a test mixture. The mixture is incubated for a time sufficient to permit competition between any analyte present and the conjugate for the binding material. Following incubating, the mixture is allowed to traverse the absorbent material from the contact portion through the measurement portion of the absorbent material. Following traversal by the test mixture, the presence or amount of marker in the measurement portion of the absorbent material is then detected and correlated with the presence or amount, respectively, of the analyte in the sample. Also disclosed are liposomes encapsulating an electroactive marker used in conjunction with a test device as described, but which includes an electrochemical measurement portion in place of the measurement portion described above. Test devices and methods employing electrochemical detection or quantification of an electroactive marker corresponding to the amount of analyte in a sample may be either amperometric or potentiometric.
78 Citations
10 Claims
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1. A method for detecting or quantifying an analyte in a test sample, comprising:
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providing a test device comprising an absorbent material, which absorbent material comprises; a contact portion at or proximate to a first end of said absorbent material; and an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end; said electrochemical measurement portion comprising a working electrode portion, a reference electrode portion, and a counter electrode portion, wherein each of said electrode portions is segregated from one another on said absorbent material, said working, reference, and counter electrode portions are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said contact portion and said working electrode portion, wherein said liposome lysing portion is segregated from said contact portion and has a liposome lysing agent bound thereto, or said working electrode portion has a liposome lysing agent bound thereto; combining a binding material specific for the analyte with a conjugate of an analyte analog and liposomes and the test sample in an electrolyte mixture, wherein said liposomes comprise an electroactive marker; incubating the mixture for a time sufficient to permit competition between any analyte present in the test sample and the conjugate for the binding material; contacting the mixture with said contact portion of said absorbent material after said incubating; allowing the mixture to migrate from said contact portion through said electrochemical measurement portion of said absorbent material after said incubating, wherein migration of aggregates of conjugate and binding material formed during said incubating is inhibited by said absorbent material, whereby said liposomes are lysed by said liposome lysing agent to release said marker, and an electrical connection between said working, reference and counter electrode portions is established causing current to flow between said working and said counter electrode portions; detecting the presence or amount of said current flowing between said working and said counter electrode portions; and correlating the presence or amount of said current flowing between said working and said counter electrode portions with the presence or amount, respectively, of the analyte in the test sample. - View Dependent Claims (2, 3)
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4. A test device for detecting or quantifying an analyte in a test sample, said test device comprising:
an absorbent material, comprising; a contact portion at or proximate to a first end of said absorbent material; and an electrochemical measurement portion at a location on said absorbent material which is positioned away from the first end; said electrochemical measurement portion comprising a working electrode portion, a reference electrode portion, and a counter electrode portion, wherein each of said electrode portions is segregated from one another on said absorbent material, said working, reference, and counter electrode portions are electrically connected with one another, and wherein either said absorbent material further comprises a liposome lysing portion positioned between said contact portion and said working electrode portion, wherein said liposome lysing portion is segregated from said contact portion and has a liposome lysing agent bound thereto, or said working electrode portion has a liposome lysing agent bound thereto. - View Dependent Claims (5, 6, 7, 8, 9, 10)
Specification