Reagent storage in an assay device

An assay device comprising:

• (a) a storage zone comprising a storage surface to which two or more surface-reagent complexes are bound and thereby confined to said storage zone, said two or more surface-reagent complexes comprising a first surface-reagent complex and a second surface-reagent complex, wherein said first surface-reagent complex comprises:
• (i) a first reagent linked to a first targeting agent,
• (ii) a first surface linked to a second targeting agent, and
• said second surface-reagent complex comprises:
• (iii) a second reagent linked to a third targeting agent, and
• (iv) a second surface linked to a fourth targeting agent,
• wherein said first surface and said second surface are portions of the same storage surface, wherein said first reagent and said first surface and said second reagent and said second surface are linked, respectively, in said first and second surface-reagent complexes, via a selective releasable binding interaction between said first and second targeting agents and said third and fourth targeting agents, respectively, wherein said first reagent is configured to release from said first surface-reagent complex by a first set of conditions, and said second reagent is configured to release from said second surface-reagent complex by a second set of conditions, wherein the first set of conditions is different from said second set of conditions;
• and
• (b) one or more use zones each configured to use at least one of said first reagent and said second reagent in an assay for an analyte of interest in a sample.