Photoactivated chemical bleaching of dyes

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 R1, R2, and R3 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:
• R4 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).