A reaction mixture comprising: a functionalized substrate comprising a supporting material, one or more target-specific capture probes bound to the surface of the supporting material, and a plurality of synthetic, non-naturally occurring molecules bound to the surface of the supporting material wherein each of the synthetic, non-naturally occurring molecules comprises a first covalent bond-forming reactive group; a plurality of functionalized detectable label particles, wherein each of the plurality of functionalized detectable label particles comprises a plurality of molecules bound to the surface of a detectable label particle to provide a functionalized detectable label particle, and wherein each of the plurality of molecules bound to the surface of the detectable label particle comprises a member of a specific binding pair; a plurality of linker molecules wherein each linker molecule in the plurality of linker molecules is configured to bind one of the plurality of molecules bound to the surface of the functionalized detectable label particles, and wherein each linker molecule comprises a plurality of second covalent bond-forming reactive groups; a target specific label probe; and an enzyme conjugate configured to specifically bind the target-specific label probe and catalyze the formation of covalent bonds between the first covalent bond-forming reactive groups and the second covalent bond-forming reactive groups. a functionalized substrate comprising a supporting material, one or more target-specific capture probes bound to the surface of the supporting material, and a plurality of synthetic, non-naturally occurring molecules bound to the surface of the supporting material wherein each of the synthetic, non-naturally occurring molecules comprises a first covalent bond-forming reactive group; a supporting material, one or more target-specific capture probes bound to the surface of the supporting material, and a plurality of synthetic, non-naturally occurring molecules bound to the surface of the supporting material wherein each of the synthetic, non-naturally occurring molecules comprises a first covalent bond-forming reactive group; a plurality of functionalized detectable label particles, wherein each of the plurality of functionalized detectable label particles comprises a plurality of molecules bound to the surface of a detectable label particle to provide a functionalized detectable label particle, and wherein each of the plurality of molecules bound to the surface of the detectable label particle comprises a member of a specific binding pair; a plurality of linker molecules wherein each linker molecule in the plurality of linker molecules is configured to bind one of the plurality of molecules bound to the surface of the functionalized detectable label particles, and wherein each linker molecule comprises a plurality of second covalent bond-forming reactive groups; a target specific label probe; and an enzyme conjugate configured to specifically bind the target-specific label probe and catalyze the formation of covalent bonds between the first covalent bond-forming reactive groups and the second covalent bond-forming reactive groups. wherein each of the plurality of functionalized detectable label particles comprises a plurality of molecules bound to the surface of a detectable label particle to provide a functionalized detectable label particle, and wherein each of the plurality of molecules bound to the surface of the detectable label particle comprises a member of a specific binding pair; a plurality of linker molecules wherein each linker molecule in the plurality of linker molecules is configured to bind one of the plurality of molecules bound to the surface of the functionalized detectable label particles, and wherein each linker molecule comprises a plurality of second covalent bond-forming reactive groups; a target specific label probe; and an enzyme conjugate configured to specifically bind the target-specific label probe and catalyze the formation of covalent bonds between the first covalent bond-forming reactive groups and the second covalent bond-forming reactive groups.