Universal Scaffold for an Activatable Photosensitizer with Completely Inhibited Photosensitivity

Area of Science:

• Medicinal Chemistry
• Photodynamic Therapy
• Biomarker Detection

Background:

• Activatable photosensitizers (aPSs) offer targeted therapeutic potential for photodynamic therapy (PDT).
• Current aPSs often lack efficient activation and recovery mechanisms in response to specific disease biomarkers.
• Developing stimuli-responsive photosensitizers is crucial for advancing targeted PDT strategies.

Purpose of the Study:

• To design and synthesize novel activatable photosensitizers (aPSs) with biomarker-specific activation and recovery capabilities.
• To demonstrate the intracellular activation and enhanced photosensitivity of designed aPSs.
• To create a modular platform for customizing aPSs for specific PDT applications.

Main Methods:

• Design and synthesis of a long-wavelength D-π-A photosensitizer (PS_Se-I) for efficient singlet oxygen (¹O₂) generation.
• Caging of the photosensitizer with biomarker-sensitive groups to create ^ALP PS for intracellular activation studies.
• Introduction of a clickable azide group for modular functionalization, leading to the synthesis of ^mito-PN PS with targeting and trigger functionalities.

Main Results:

• Demonstrated drastic activation of photosensitivity for ^ALP PS intracellularly upon biomarker presence.
• Successfully synthesized modular ^mito-PN PS, incorporating mitochondria-targeting and peroxynitrite-reactive elements.
• ^mito-PN PS exhibited superior performance in cellular studies, highlighting its potential for targeted PDT.

Conclusions:

• The developed strategy enables the creation of activatable photosensitizers that can be triggered by specific biomarkers.
• The modular design allows for customization of aPSs, enhancing their applicability in diverse PDT scenarios.
• This approach holds significant promise for developing next-generation targeted therapies for various diseases.