pH-Sensitive and Lysosome Targetable Photosensitizers Based on BODIPYs.

Area of Science:

• Organic Chemistry
• Photochemistry
• Biomedical Engineering

Background:

• Photodynamic therapy (PDT) is an FDA-approved treatment modality for various diseases, including cancer.
• Photosensitizers are crucial for PDT, harvesting light energy to initiate therapeutic effects.
• Boron dipyrromethene (BODIPY) derivatives are emerging as promising photosensitizers due to their tunable properties, low dark toxicity, and compatibility with other treatments.

Purpose of the Study:

• To synthesize novel pH-sensitive BODIPY-based photosensitizers.
• To investigate the photophysical properties and singlet oxygen generation of the synthesized compounds.
• To evaluate the cellular uptake, organelle targeting, and photodynamic therapeutic potential of the developed photosensitizers.

Main Methods:

• Synthesis of two pH-sensitive BODIPY derivatives (BDC and BDBrC) via condensation reactions, incorporating carbazole moieties.
• Characterization of absorption and emission properties, and assessment of pH sensitivity.
• Evaluation of singlet oxygen generation, cellular uptake, lysosomal targeting, dark cytotoxicity, and light-triggered phototoxicity.

Main Results:

• BDC and BDBrC were successfully synthesized, exhibiting pH sensitivity with enhanced singlet oxygen generation under acidic conditions.
• BDBrC demonstrated selective targeting of the lysosome organelle in cellular imaging experiments.
• The synthesized compounds showed low dark toxicity and significant light-triggered cytotoxicity, indicating potential for PDT.

Conclusions:

• The developed BODIPY-based photosensitizers, particularly BDBrC, are effective for pH-sensitive photodynamic therapy.
• BDBrC's ability to target lysosomes and generate singlet oxygen under acidic conditions makes it a promising candidate for targeted cancer treatment.
• These findings highlight the potential of tailored BODIPY derivatives in advancing PDT applications.