Reagent Storage in an Assay Device

Abstract

The invention relates to methods for conducting binding assays in an assay device that includes one or more storage and use zone. The storage zones of the assay device are configured to house one or more reagents used in an assay conducted in the use zone of the device.

1 . An assay device comprising
 (a) a storage zone comprising a surface-reagent complex confined to said storage zone, said surface-reagent complex comprising
 (i) a reagent linked to a first targeting agent; and 
 (ii) a surface linked to a second targeting agent, 
   wherein said reagent and said surface are linked, in said surface-reagent complex, via a releasable binding interaction between said first and second targeting agents; and   (b) one or more use zones each configured to use said reagent in an assay for an analyte of interest in a sample.   
     
     
         2 . The assay device of  claim 1  wherein said one or more use zones each comprise an additional reagent used in said assay. 
     
     
         3 . The assay device of  claim 1  wherein said reagent is a binding reagent that binds a component of said assay conducted in said use zone. 
     
     
         4 . The assay device of  claim 3  wherein said binding reagent binds said analyte. 
     
     
         5 . The assay device of  claim 2  wherein said additional reagent binds said analyte. 
     
     
         6 . The assay device of  claim 4  wherein said binding reagent binds a complex formed between said additional reagent and said analyte. 
     
     
         7 . The assay device of  claim 6  wherein said one or more use zones each comprise a solid support and said additional reagent is bound to said solid support. 
     
     
         8 . The assay device of  claim 1  wherein said reagent comprises a detectable label. 
     
     
         9 . The assay device of  claim 8  wherein said detectable label is an ECL label. 
     
     
         10 . The assay device of  claim 1  wherein said storage zone and said one or more use zones are in fluidic communication along a fluid path. 
     
     
         11 . The assay device of  claim 1  wherein said one or more use zones each comprise two or more assay regions each configured to use said reagent in one or more assays conducted with said sample in said assay device. 
     
     
         12 . The assay device of  claim 11  wherein a first assay region of said one or more use zones is configured to conduct an assay for a first analyte of interest in said sample and an additional assay region in said one or more use zones is configured to conduct an assay for an additional analyte of interest in said sample. 
     
     
         13 . The assay device of  claim 11  wherein a first assay region of said one or more use zones is configured to conduct a first assay for said analyte of interest in said sample and an additional assay region of said one or more use zones is configured to conduct a second assay for said analyte of interest in said sample. 
     
     
         14 . The assay device of  claim 11  wherein each of said two or more assay regions comprise an additional reagent used in said assay. 
     
     
         15 . The assay device of  claim 14  wherein said additional reagent is an additional binding reagent. 
     
     
         16 . The assay device of  claim 11  wherein said one or more use zones each comprise an array of said two or more assay regions. 
     
     
         17 . The assay device of  claim 1  wherein said surface is a particle. 
     
     
         18 . The assay device of  claim 1  wherein said surface is roughened such that the surface area accessible to a component capable of binding to said surface is at least three-fold larger than the surface area of a flat surface. 
     
     
         19 . The assay device of  claim 1  wherein said surface is roughened such that the surface area accessible to a component capable of binding to said surface is at least two-fold larger than the surface area of a flat surface. 
     
     
         20 . The assay device of  claim 1  wherein said surface comprises a composite material including exposed particles distributed in a matrix. 
     
     
         21 . The assay device of  claim 20  wherein said composite material comprises carbon particles, graphitic particles, or carbon nanotubes. 
     
     
         22 . The assay device of  claim 20  wherein said composite is etched. 
     
     
         23 . The assay device of  claim 20  wherein said surface comprises one or more indentations and/or raised features. 
     
     
         24 . The assay device of  claim 1  wherein said surface comprises a hydrogel. 
     
     
         25 . The assay device of  claim 1  wherein said reagent is released from said surface-reagent complex by subjecting said storage zone to increased or decreased temperature, pH changes, an electric potential, a change in ionic strength, competition, and combinations thereof. 
     
     
         26 . The assay device of  claim 25  wherein said reagent is released by subjecting said storage zone to increased temperature. 
     
     
         27 . The assay device of  claim 26  wherein said increased temperature exceeds the melting temperature of said binding interaction. 
     
     
         28 . The assay device of  claim 1  wherein said assay device is a cartridge. 
     
     
         29 . The assay device of  claim 1  wherein said assay device is a multi-well assay plate and said use zone is positioned within a well of said assay plate. 
     
     
         30 . The assay device of  claim 29  wherein said storage zone is located on a supplemental surface of said well that does not overlap with said use zone. 
     
     
         31 . The assay device of  claim 1  wherein said device is configured to conduct a multiplexed measurement. 
     
     
         32 . A method of conducting an assay for an analyte of interest in a sample, wherein said method is conducted in an assay device comprising:
 (a) a storage zone comprising a surface-reagent complex confined to said storage zone, said surface-reagent complex comprising
 (i) a reagent linked to a first targeting agent; and 
 (ii) a surface linked to a second targeting agent, 
   wherein said reagent and said surface are linked, in said surface-reagent complex, via a releasable binding interaction between said first and second targeting agents; and   (b) one or more use zones each configured to use said reagent in an assay for an analyte of interest in a sample;   said method comprising:   (x) introducing said sample to said one or more use zones;   (y) subjecting said storage zone to a condition that releases said reagent from said surface-reagent complex;   (z) transferring said reagent from said storage zone to said one or more use zones; and   (xx) conducting said assay in said one or more use zones with said reagent.   
     
     
         33 . The method of  claim 32  wherein said condition is selected from increased or decreased temperature, pH changes, applying an electrical potential, a change in ionic strength, competition, and combinations thereof. 
     
     
         34 . The method of  claim 32  wherein said condition comprises increasing the temperature of said storage zone. 
     
     
         35 . The method of  claim 34  wherein said increased temperature exceeds the melting temperature of said binding interaction. 
     
     
         36 . The method of  claim 32  wherein said reagent is a binding reagent that binds said analyte and said method further comprises detecting the amount of analyte bound to said binding reagent in said one or more use zones. 
     
     
         37 . The method of  claim 36  wherein said reagent comprises a detectable label and said detecting step comprises detecting the presence or absence of said detectable label in said one or more use zones. 
     
     
         38 . The method of  claim 37  wherein said detectable label is an ECL label and said detecting step comprises detecting electrochemiluminescence emitted in said one or more use zones. 
     
     
         39 . The method of  claim 32  wherein said storage zone and said one or more use zones are in fluidic communication along a fluid path and said transferring step (z) comprises transferring said reagent from said storage zone via said fluid path to said one or more use zones. 
     
     
         40 . The method of  claim 32  wherein said use zone comprises two or more assay regions each configured to use said reagent in one or more assays conducted with said sample in said assay device, said method further comprising the step of conducting a plurality of assays in said one or more use zones with said reagent. 
     
     
         41 . The method of  claim 40  wherein said one or more use zones each comprise a first assay region configured to conduct an assay for a first analyte of interest in said sample and an additional assay region configured to conduct an assay for an additional analyte of interest in said sample, said method comprising:
 (x) introducing said sample to said one or more use zones; 
 (y) subjecting said storage zone to a condition that releases said reagent from said surface-reagent complex; 
 (z) transferring said reagent from said storage zone to said first assay region and said second assay region; 
 (xx) conducting said assays in said first and second assay regions, respectively. 
 
     
     
         42 . The method of  claim 41  wherein said assays are conducted simultaneously. 
     
     
         43 . The method of  claim 41  wherein said assays are conducted sequentially.