Abstract: Provided is a photoamplified fluorescence turn-off assay where a masked photosensitizer is mixed with a fluorescent molecule. This mixture is brightly fluorescent because the masked photosensitizer is not capable of quenching the fluorophore. When the photosensitizer is released and amplified, the photosensitizer quenches the emission of fluorophores very efficiently.

Abstract: Provided is a photoamplified fluorescence turn-off assay where a masked photosensitizer is mixed with a fluorescent molecule. This mixture is brightly fluorescent because the masked photosensitizer is not capable of quenching the fluorophore. When the photosensitizer is released and amplified, the photosensitizer quenches the emission of fluorophores very efficiently.

Abstract: A method of screening a library comprising: (i) providing either (a) a library comprising more than one copy of different library members, each copy of a different library member attached to a different releasable tag through a releasable covalent bond; where a plurality of tags uniquely encode each library member; or (b) a library comprising one or more copies of a library member attached to a support, with a plurality of tags uniquely encoding each library member; or (c) a library comprising different library members, each different library member attached to a plurality of tags uniquely encoding the different library member; (ii) providing a target compound with tethered sensitizer in specific binding proximity to the library, allowing specific binding of the target compound with tethered sensitizer to a selected library member; (iii) exciting the tethered sensitizer with excitation photoradiation, whereby the releasable tags attached to the selected library member are released; and (iv) detecting the rele

Abstract: A method of photochemically amplifying the chemical signal associated with unmasking a photosensitizer and releasing a radical leaving group when a photochemical chain reaction is initiated by a sensitizer attached to a molecule of interest is provided. More specifically, provided is a method of photoinduced amplification comprising: providing a plurality of masked photosensitizers, each masked photosensitizer having a masking group bonded to a photosensitizer through a releasable covalent bond which disrupts the conjugation of the photosensitizer; providing a reaction photosensitizer in releasing proximity to a first masked photosensitizer; exciting the reaction photosensitizer with photoradiation, whereby the reaction photosensitizer induces release of the masking group from the first masked photosensitizer, producing a first unmasked photosensitizer which induces release of the masking group from a second masked photosensitizer in releasing proximity to the first masked photosensitizer, and so on.

Abstract: A method of photofragmentation is provided comprising: providing a masked fluorescent molecule having a masking group bonded to a fluorescent molecule through a photolabile covalent bond; exposing the masked fluorescent molecule to cleaving photoradiation, producing an unmasked fluorescent molecule; detecting the fluorescence of the unmasked fluorescent molecule. The photolabile covalent bond disrupts the conjugation of the fluorescent molecule, causing the fluorescence to be masked. When the photolabile covalent bond is broken, the conjugation is restored, resulting in an increase in fluorescence of the fluorescent molecule as compared to the masked fluorescent molecule.