Assay Devices and Methods for the Detection of Analytes

Abstract

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 - 127 . (canceled) 
     
     
         128 . A method, comprising:
 forming a composition of matter comprising:   a liquid sample comprising an analyte,   a detectable label capable of forming a complex comprising the analyte,   a compressible medium comprising a surface capable of capturing the detectable label in the presence of the analyte, the surface occupying a total volume,   capturing at least some of the detectable label with respect to the surface,   with the compressible medium positioned between first and second opposed surfaces of a reaction chamber, decreasing the total volume occupied by the surface by reducing a distance separating the first and second opposed surfaces such that the liquid sample is displaced from between the surfaces without removing the liquid sample from the reaction chamber, and   with the surface in the decreased-total volume state, determining the presence of the captured detectable label, wherein the method optionally further comprises determining the presence of the analyte based on the presence of the captured detectable label.   
     
     
         129 . The method of  claim 128 , wherein the method is performed without contacting the surface with a liquid free of detectable label intermediate the steps of capturing at least some of the detectable label and determining the presence of the captured detectable label, or wherein the step of determining the presence of the captured detectable label is performed at least in part with the surface in contact with the liquid sample of the composition of matter. 
     
     
         130 . The method of  claim 128 , wherein decreasing the total volume occupied by the surface comprises decreasing the total volume by a factor of at least 5. 
     
     
         131 . The method of  claim 128 , wherein the compressible medium is a porous compressible medium having a total surface area and the surface capable of capturing the detectable label occupies only a portion of the total surface area of the compressible medium. 
     
     
         132 . The method of  claim 128 , wherein:
 forming the composition of matter comprises forming the composition of matter to comprise:   an integer N A  different analytes, where N A ≧0, N A ≧5 or N A ≧10,   an integer N L  different detectable labels each capable of forming a complex comprising a respective one of the N A  analytes, where N L ≧N A ,   an integer N S  surface portions, each surface portion is a surface of a compressible medium, each surface portion is capable of capturing a respective one of the N L  detectable labels in the presence of a respective one of the N A  analytes, each of the N S  surface portions occupies a respective total volume, and where N S ≧N L ,   capturing at least some of the detectable label comprises capturing each of multiple respective N L  different detectable labels with respect to a respective N S  surface portion, decreasing the total volume occupied by the surface comprises decreasing the respective total volume occupied by each of the N S  surface portions, and   the method further comprises, determining the presence of the captured detectable labels with the N S  surface portions in the decreased volume state, optionally further comprising determining the presence of the N A  analytes based on the presence of captured detectable labels of the N L  labels.   
     
     
         133 . The method of  claim 132 , wherein each of the N S  surface portions is a different portion of a surface of a single compressible medium, wherein the compressible medium is optionally a porous medium. 
     
     
         134 . The method of  claim 133 , wherein, prior to decreasing the total volume occupied by each of the N S  surface portions, the compressible medium occupies a total volume of about 25 mm 3  or less, of about 5 mm 3  or less, of at least about 5 mm 3 , of at least about 1 mm 3  or of about 1×10 −1  mm 3  or less. 
     
     
         135 . The method of  claim 128 , wherein the composition comprises at least some detectable label that has not been captured by the surface, the step of decreasing the total volume occupied by the surface is performed with the composition positioned between first and second opposed surfaces and this step comprises displacing at least some un-captured detectable label from between the first and second surfaces. 
     
     
         136 . The method of  claim 128 , further comprising, prior to the step of decreasing the total volume occupied by the surface, performing a cycle comprising decreasing the total volume occupied by the surface and increasing the total volume occupied by the surface. 
     
     
         137 . The method of  claim 136 , comprising performing an integer N C  cycles, where N C ≧1, N C ≧10 or N C ≧20. 
     
     
         138 . The method of  claim 137 , comprising, in each of an integer N D  of the N C  cycles and each time with the surface in the decreased-volume state, determining the presence of the captured detectable label, and where N D ≦N C . 
     
     
         139 . The method of  claim 128 , wherein the step of decreasing the total volume occupied by the surface is performed with the composition positioned between first and second opposed surfaces and the step of determining the presence of the captured detectable label comprises detecting an optical signal transmitted through at least one of the first and second opposed surfaces. 
     
     
         140 . The method of  claim 128 , wherein the step of decreasing the total volume occupied by the surface is performed with the composition positioned between first and second opposed surfaces and comprises reducing a separation distance between the first and second opposed surfaces from an initial distance of about 2 mm or less to a decreased distance of about 0.5 mm or less, of about 0.2 mm or less or of about 1 mm or less. 
     
     
         141 . The method of  claim 128 , further comprising, prior to the step of determining the presence of the captured detectable label, causing motion of the liquid sample with respect to the surface occupying the total volume. 
     
     
         142 . The method of  claim 141 , wherein the step of causing motion of the liquid sample is performed prior to decreasing the total volume, or wherein causing motion of the liquid comprises causing at least some of the liquid sample to exit and then re-enter the total volume occupied by the surface and/or wherein causing motion of the liquid sample optionally comprises causing at least some of the liquid sample to exit and then re-enter the total volume multiple times. 
     
     
         143 . The method of  claim 141 , wherein the compressible medium is a porous compressible medium and the step of causing motion comprises moving at least some of the liquid sample, at least some of the analyte, and at least some of the detectable label within pores of the compressible medium. 
     
     
         144 . The method of  claim 143 , wherein at least some of the surface capable of capturing the detectable label in the presence of the analyte is within the pores of the compressible medium, and/or wherein the step of capturing optionally comprises capturing at least some of the detectable label within the pores of the compressible medium. 
     
     
         145 . The method of  claim 128 , wherein a portion of the compressible medium is secured to one of the first and second opposed surfaces. 
     
     
         146 . The method of  claim 128 , wherein a first portion of the compressible medium is secured to the first opposed surface, a second portion of the compressible medium is secured to the second opposed surface, and the first and second portions are separated by at least some of the compressible medium and/or wherein the compressible medium separating the first and second portions optionally comprises the surface capable of capturing the detectable label. 
     
     
         147 . The method of  claim 128 , wherein each of the first and second opposed surfaces is an inner surface of a respective wall impermeable to the liquid sample of the composition. 
     
     
         148 . A device, comprising:
 a support member comprising multiple capture sites, the multiple capture sites disposed 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 a liquid sample comprising 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 when the capture sites are in the decreased-volume state, wherein the support member is positioned between first and second surfaces of a reaction chamber impermeable to the liquid and the liquid mixture is displaced from between the surfaces without removing the liquid mixture from the reaction chamber when the actuator decreases the total volume occupied by the capture sites.   
     
     
         149 . The device of  claim 148 , wherein the support member is a porous compressible medium, and/or wherein the device is optionally configured to flow at least some of the liquid mixture through pores of the compressible medium, and/or wherein the device is optionally 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 and/or wherein the device is optionally configured to cause at least some of the liquid mixture to repeatedly exit and re-enter pores of the compressible medium. 
     
     
         150 . The device of  claim 148 , wherein the support member comprises an integer N S  sets of capture sites, the multiple capture sites of each set (a) being disposed in three dimensions, (b) together occupying a respective total volume, and (c) being capable of capturing a respective detectable label in the presence of a respective analyte, the support member is configured to accommodate a mixture comprising an integer N L  different detectable labels and an integer N A  different analytes, and where N S ≧N L ≧N A ≧0,
 the actuator is configured to decrease the total volume occupied by the capture sites of each set of capture sites, and 
 the detector is configured to determine the presence of detectable label captured at capture sites of each of the N S  captures sites when the capture sites are in the decreased-volume state, wherein the detector optionally comprises an multidimensional array of optical detectors configured to receive light from the N S  captures sites. 
 
     
     
         151 . The device of  claim 148 , wherein the device further comprises a reservoir configured to receive displaced liquid and/or wherein the reservoir comprises at least one expandable member configured to expand upon receiving displaced liquid. 
     
     
         152 . The device of  claim 148 , 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.