Photoactivated chemical bleaching of dyes

1. A method of probing multiple targets in a biological sample comprising:

(a) providing a biological sample containing multiple targets;

(b) binding at least one probe to the biological sample and wherein said probe comprises a binder and at least one of a optical signal generator or a fluorescent signal generator and wherein the binder is capable of binding specifically to one or more targets in the biological sample;

(c) observing a signal from the at least one probe bound in step (b);

(d) contacting the biological sample comprising the bound probe of step (b) with an electron transfer reagent, wherein the electron transfer reagent is a borate salt represented by the following structural formula:

wherein:

each R 1 , R 2 , and R 3 is, independently, an alkyl, an alkenyl, an akynyl, an aryl or a heteroaryl, wherein said alkyl, alkenyl, alkynyl, aryl or heteroaryl is optionally substituted with one or more substituents selected from the group consisting of (C1-C4)alkyl, (C1-C4)alkoxy, (C1-C4)alkylamino, amino, hydroxyl, cyano, halogen, or nitro:

R 4 is an alkyl, an alkenyl, or an akynyl, wherein said alkyl, alkenyl, or alkynyl is optionally substituted with one or more substituents selected from the group consisting of (C1-C4)alkyl, (C1-C4)alkoxy, (C1-C4)alkylamino amino, hydroxyl, cyano, halogen, or nitro: and

M + is selected from the group consisting of organic and inorganic cations;

(e) irradiating the biological sample of step (d);

(f) binding at least one probe to one or more targets present in the sample of step (e); and

(g) observing a signal from the probe bound in step (f).

2. The method of claim 1 , wherein the probe in step (b) comprises an optical signal generator, and the signal observed in step (c) is an optical signal.

3. The method of claim 2 , wherein the probe in step (b) comprises a fluorescent signal generator, and the signal observed in step (c) is a fluorescent signal.

4. The method of claim 1 , wherein irradiating the sample in step (e) is carried out in the presence of a buffer at pH of 5-9.

5. The method of claim 1 , wherein steps (d) and (e) are carried out at the temperature of 4-50° C.

6. The method of claim 1 , wherein irradiating the sample in step (e) is accomplished by exposing the sample to light of 350 nm-1.3 μM in wavelength.

7. The method of claim 6 , wherein irradiating the sample in step (e) is accomplished by exposing the sample to light of 400-700 nm in wavelength.

8. The method of claim 1 , wherein each R 1 , R 2 , and R 3 is an optionally substituted aryl and R 4 is an optionally substituted alkyl.

9. The method of claim 8 , wherein each R 1 , R 2 , and R 3 is unsubstituted phenyl and R 4 is unsubstituted butyl, and the borate salt is triphenylbutyl borate salt.

10. The method of claim 1 , wherein M + is an inorganic cation selected from the group consisting of Li + , Na + or K + .

11. The method of claim 3 , wherein the fluorescent signal generator comprises a cyanine dye.

12. The method of claim 11 , wherein the cyanine dye is Cy3 or Cy5.

13. The method of claim 1 , wherein steps (d)-(g) are repeated one or more times.

14. The method of claim 1 , wherein the steps (d) and (e) are performed for about 20 seconds to about 15 minutes.

15. The method of claim 1 , further comprising measuring one or more intensity values of the signal observed in observing step (c), step (g), or steps (c) and (g).

16. The method of claim 15 , further comprising correlating the intensity value with an amount of target present in the sample.

17. The method of claim 1 , wherein the probe in step (b) and the probe in step (f) each comprise a signal generator, wherein the signal generator in step (b) is different from the signal generator in step (f).