Assay devices and methods for the detection of analytes
The present invention relates to devices and methods for performing assays, especially for determining the presence and/or amount of one or more analytes. In particular, the invention relates to a device for the detection of analytes, comprising a reversibly compressible matrix located between a first surface and a second surface, wherein the second surface is located opposite to the first surface, and wherein the distance between the first surface and the second surface is variable. The invention also relates to a corresponding method using such a device for the detection of one or more species of analytes.
1. A method, comprising:
contacting a set of capture sites comprising multiple capture sites, with a mixture comprising a detectable label and an analyte, the multiple capture sites disposed in a compressible medium in three dimensions and together occupying a total volume, each of the capture sites being capable of capturing the detectable label in the presence of the analyte,
capturing at least some of the detectable label with respect to each of some of the capture sites,
decreasing the total volume occupied by the multiple capture sites, and with the multiple capture sites in the decreased volume state, determining the presence of the captured detectable label supported by the compressible medium.
2. The method of claim 1 , further comprising, prior to the step of decreasing the total volume occupied by the multiple capture sites, performing a cycle comprising decreasing the total volume occupied by the multiple capture sites and increasing the total volume occupied by the multiple capture sites.
3. The method of claim 2 , comprising performing an integer number of cycles, where the integer number of cycles ≧1.
4. The method of claim 1 , wherein the mixture comprises a liquid.
5. The method of claim 4 , further comprising, prior to the step of determining the presence of the captured detectable label, causing movement of the liquid with respect to the capture sites of the set.
6. The method of claim 5 , wherein causing movement of the liquid comprises causing at least some of the liquid to be removed and then to be re-added to the total volume occupied by the capture sites of the set.
7. The method of claim 1 , wherein the compressible medium is a porous compressible medium and the step of causing motion comprises moving at least some of the liquid, at least some of the analyte, and at least some of the detectable label within pores of the compressible medium.
8. The method of claim 7 , wherein the step of capturing comprises capturing at least some of the detectable label within the pores of the compressible medium.
9. The method of claim 1 , wherein the step of decreasing the total volume is performed with the mixture positioned between first and second opposed surfaces and this step comprises reducing a distance separating the first and second opposed surfaces.
10. The method of claim 9 , wherein the capture sites of the set of capture sites are supported by a compressible medium and a portion of the compressible medium is secured to one of the first and second opposed surfaces.
11. A device, comprising:
a support member comprising a set of capture sites comprising multiple capture sites, the multiple capture sites disposed in a compressible medium in three dimensions about the member and together occupying a total volume, each of the capture sites capable of capturing a detectable label in the presence of a common analyte, the support member configured to accommodate a liquid mixture in contact with the capture sites, the liquid mixture comprising the detectable label and the analyte,
an actuator configured to decrease the total volume occupied by the capture sites, and a detector configured to determine the presence of captured detectable label attached to the support member when the capture sites are in the decreased-volume state.
12. The device of claim 11 , wherein the support member is a porous compressible medium.
13. The device of claim 12 , wherein the device is configured to flow at least some of the liquid mixture through pores of the compressible medium.
14. The device of claim 13 , wherein the device is configured to cause at least some of the liquid mixture to re-enter pores of the compressible medium after exiting pores of the compressible medium.
15. The device of claim 11 , wherein the support member is positioned between first and second surfaces impermeable to the liquid and at least some of the liquid mixture is displaced from between the surfaces when the actuator decreases the total volume occupied by the capture sites.
16. The device of claim 15 , further comprising a reservoir configured to receive displaced liquid.
17. The device of claim 11 , further comprising a processor configured to operate the actuator and detector and to determine the presence of the analyte based on the presence of the captured detectable label.