Double Disguise: Camouflaging Photocages for Bioorthogonally Controlled Conditional Activation.

Area of Science:

• Chemical Biology
• Organic Chemistry
• Drug Delivery

Background:

• Photocages offer precise spatiotemporal control in biological systems.
• Current photocage activation strategies have limitations in specificity.
• Aminofluorone (rhodol) chromophore-based photocages were previously developed.

Purpose of the Study:

• To develop photocages with an additional layer of controllable activation.
• To introduce substitution-dependent, bioorthogonally regulated photoactivation.
• To demonstrate the utility of these photocages in a cellular context.

Main Methods:

• Chemical modification of rhodol photocages by substituting the oxygen auxochrome.
• Assessment of photocage photoactivity and colorlessness in the disabled state.
• Bioorthogonal removal of the camouflaging group to restore photoactivity.
• Cellular experiments involving light and bioorthogonal reagents to release a drug.

Main Results:

• Substitution on the oxygen auxochrome rendered rhodol photocages completely inactive and colorless.
• Bioorthogonal removal of the substituent restored photocage photoactivity.
• Demonstrated controlled release of SN38 (a topoisomerase inhibitor) in cells using both light and a bioorthogonal reagent.

Conclusions:

• Camouflaged photocages offer enhanced control over photoactivation.
• This strategy enables substitution-dependent, bioorthogonally regulated photoactivation.
• The developed photocages are effective for targeted drug delivery in a cellular environment.