Droplet-based affinity assays
First Claim
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1. A method of detecting a target analyte in a sample, the method comprising:
- (a) executing electrowetting-mediated droplet operations using droplets on a droplet microactuator to effect an immunoassay, wherein the electrowetting-mediated droplet operations are selected to;
(i) combine one or more immunoassay reagent droplets comprising an antibody immobilized on one or more magnetically-responsive beads disposed in a droplet with a sample droplet potentially comprising the target analyte to yield a combined droplet, wherein the one or more immunoassay reagent droplets, the sample droplet, and the combined droplet are each;
(1) arranged on the droplet microactuator; and
(2) subject to the electrowetting-mediated droplet operations; and
(ii) effect a droplet-based washing protocol on the droplet microactuator using a droplet comprising the magnetically responsive beads, wherein the washing protocol comprises conducting droplet operations selected to;
(1) merge one or more wash buffer droplets with a droplet comprising the magnetically responsive beads; and
(2) split the droplet comprising the magnetically responsive beads, while using a magnet to retain the magnetically responsive beads, thereby removing a sub-droplet comprising unbound substances from a sub-droplet comprising the beads; and
(b) generating and detecting a signal which corresponds to the presence, absence and/or quantity of the analyte in the sample.
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Abstract
The present invention relates to droplet-based affinity assays. According to one embodiment, a method of detecting a target analyte in a sample is provided, wherein the method includes: (a) executing droplet operations to combine affinity-based assay reagents on a droplet microactuator with a sample potentially comprising the target analyte to generate a signal indicative of the presence, absence and/or quantity of analyte; and (b) detecting the signal, wherein the signal corresponds to the presence, absence and/or quantity of the analyte in the sample.
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Citations
37 Claims
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1. A method of detecting a target analyte in a sample, the method comprising:
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(a) executing electrowetting-mediated droplet operations using droplets on a droplet microactuator to effect an immunoassay, wherein the electrowetting-mediated droplet operations are selected to; (i) combine one or more immunoassay reagent droplets comprising an antibody immobilized on one or more magnetically-responsive beads disposed in a droplet with a sample droplet potentially comprising the target analyte to yield a combined droplet, wherein the one or more immunoassay reagent droplets, the sample droplet, and the combined droplet are each; (1) arranged on the droplet microactuator; and (2) subject to the electrowetting-mediated droplet operations; and (ii) effect a droplet-based washing protocol on the droplet microactuator using a droplet comprising the magnetically responsive beads, wherein the washing protocol comprises conducting droplet operations selected to; (1) merge one or more wash buffer droplets with a droplet comprising the magnetically responsive beads; and (2) split the droplet comprising the magnetically responsive beads, while using a magnet to retain the magnetically responsive beads, thereby removing a sub-droplet comprising unbound substances from a sub-droplet comprising the beads; and (b) generating and detecting a signal which corresponds to the presence, absence and/or quantity of the analyte in the sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A method of detecting a target analyte in a sample, the method comprising executing the following electrowetting-mediated droplet operations on a droplet microactuator:
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(a) merging a droplet comprising the magnetically responsive beads with a sample droplet potentially including the target analyte with binding affinity for the immobilized antibody and yielding, in the presence of a target analyte, an immobilized antibody-target analyte complex; (b) washing the immobilized antibody-target analyte complex thereby removing unbound components of the sample droplet, wherein the washing comprises; (i) merging one or more wash droplets with a droplet comprising the one or more magnetically responsive beads and unbound components; and (ii) splitting a droplet comprising the one or more magnetically responsive beads and unbound components, while using a magnet to immobilize the magnetically responsive beads, thereby yielding a sub-droplet comprising the magnetically responsive beads and a sub-droplet substantially lacking the magnetically responsive beads; (c) merging a droplet comprising the magnetically responsive beads and washed antibody-target analyte complex with a droplet including a reporter antibody; (d) washing away excess reporter antibody, wherein the washing comprises; (i) merging one or more wash droplets with a droplet comprising the one or more magnetically responsive beads and excess reporter antibody; and (ii) splitting a droplet comprising the one or more magnetically responsive beads and excess reporter antibody while magnetically retaining the magnetically responsive beads, thereby yielding a sub-droplet comprising the magnetically responsive beads and a sub-droplet substantially lacking the magnetically responsive beads; and (e) performing additional steps to produce a measurable parameter or signal.
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Specification