Multiplexed catalyzed reporter deposition

1. A method for testing a sample for the presence of one or more targets comprising:

(1) contacting a sample being tested for the presence of one or more targets with one or more target-specific binding partners, wherein each target-specific binding partner is linked to a nucleic acid strand and wherein target-specific binding partners of different specificity are linked to different nucleic acid strands;

(2) optionally removing unbound target-specific binding partners;

(3) contacting the sample from step (1) or optionally step (2) with an enzyme linked to a nucleic acid strand complementary to the nucleic acid strand linked to the target-specific binding partner

(4) optionally removing unbound enzyme linked to complementary nucleic acid strands;

(5) contacting the sample from step (3) or optionally step (4) with a substrate conjugate comprised of a nucleic acid strand-bound substrate, where the substrate and nucleic acid strand are linked optionally with a first releasable linker;

(6) optionally removing unbound substrate conjugates;

(7) optionally deactivating the bound enzymes or releasing the bound enzymes;

(8) contacting the sample from step (5) or optionally steps (6)-(7) with a nucleic acid strand bound detectable label, linked optionally with a second releasable linker, where the nucleic acid strand is a specific binding pair member to the nucleic acid strand in step (5), and wherein either or both the first and second releasable linkers are present;

(9) imaging the sample to detect the bound labels;

(10) releasing the bound label by releasing the first releasable linker or the second releasable linker or both; and

(11) optionally repeating steps (1)-(10) or any subset thereof and optionally if more than one target-specific binding partner is used, repeating steps (1)-(8) or any subset thereof prior to step (9) of imaging.

2. The method of claim 1 ,

(3) wherein in step (3) the following (i) or (ii) or both is met:

(i) the nucleic acid strand is linked to the target-specific binding partner with a third releasable linker; and

(ii) the enzyme is linked to the complimentary complementary nucleic acid strand with a fourth releasable linker.

3. The method of claim 1 , wherein the bound label is released by dehybridization of the nucleic acid strand from step (8) bound to the nucleic acid strand from step (5).

4. The method of claim 1 , wherein the method further comprises amplifying the nucleic acid strand or a portion thereof of the nucleic acid strand-bound substrate of step (5), optionally wherein the amplifying step is performed after step (5) or optional step (6) or optional step (7).

5. The method of claim 1 , wherein step (11) is performed.

6. The method of claim 1 , wherein the enzyme is horseradish peroxidase (HRP) and the substrate is a phenolic substrate.

7. The method of claim 1 , wherein the enzyme is deactivated using an enzyme deactivator, wherein the enzyme deactivator comprises tris(2-carboxyethyl)phosphine (TCEP), dithiothreitol (DTT), a reduced glutathione, a peroxide, a cyanide, a fluoride, or an azide.

8. The method of claim 1 , wherein in step (5), the substrate conjugate comprised of the nucleic acid strand-bound substrate reacts with the enzyme to form an activated substrate conjugate, and the activated substrate conjugate binds to a receptor for the activated substrate conjugate.

9. The method of claim 8 , wherein the receptor for the activated substrate conjugate is present in the sample, resulting in the deposition of the nucleic acid strand-bound substrates.

10. The method of claim 1 , wherein the method further comprises amplifying the nucleic acid strand or a portion thereof linked to the target-specific binding partner of step (1).

11. The method of claim 1 , further comprising after steps (9) and (10), repeating steps of (1)-(8) or a subset thereof for detection of more targets.

12. The method of claim 1 , further comprising repeating steps (3)-(8) or a subset thereof prior to step (9) of imaging for detection of more targets.

13. The method of claim 1 , wherein the method further comprises repeating steps (3)-(8) or a subset thereof prior to step (9) of imaging; and wherein after steps (9) and (10), the method comprises repeating steps (1)-(8) or a subset thereof for detection of more targets.

14. A method for testing a sample for the presence of one or more targets comprising:

(1) contacting a sample being tested for the presence of one or more targets with one or more target-specific binding partners, wherein each target-specific binding partner is linked to a nucleic acid strand and wherein target-specific binding partners of different specificity are linked to different nucleic acid strands;

(2) optionally removing unbound target-specific binding partners;

(3) contacting the sample from step (1) or optionally step (2) with an enzyme linked to a nucleic acid strand complementary to the nucleic acid strand linked to a first target-specific binding partner;

(4) optionally removing unbound enzyme linked to complementary nucleic acid strands;

(5) contacting the sample from step (3) or optionally step (4) with a substrate conjugate comprised of a nucleic acid strand-bound substrate, where the substrate and nucleic acid strand are linked with a first releasable linker;

(6) optionally removing unbound substrate conjugates;

(7) deactivating the bound enzymes or releasing the bound enzymes;

(8) optionally repeating steps (3)-(7) for a next target-specific binding partner, resulting in two or more distinct substrate conjugates bound to the sample;

(9) contacting the sample from step (8) with one or more nucleic acid strand bound detectable labels, wherein each nucleic acid strand and detectable label are linked with a second releasable linker, and each nucleic acid stand is a specific binding pair member to the nucleic acid strand of the substrate conjugate specific for the same target-specific binding partner,

(10) imaging the sample to detect the bound labels;

(11) optionally releasing the bound labels from step (8) by releasing the first releasable linker or the second releasable linker or both;

(12) optionally repeating steps (1)-(11) or any subset thereof.