Near-Infrared Conjugated Macrocyclic BODIPYs for Photothermal Cancer Therapy

Area of Science:

• Organic Chemistry
• Materials Science
• Photochemistry

Background:

• BODIPY dyes are widely used as photosensitizers.
• Controlling radiative and non-radiative decay pathways is crucial for optimizing photophysical properties.
• Developing efficient photothermal agents for cancer therapy remains a significant challenge.

Purpose of the Study:

• To develop a cyclization strategy for BODIPY-based photosensitizers to enhance photothermal conversion.
• To investigate the effect of cyclization on the photophysical properties of BODIPY derivatives.
• To evaluate the therapeutic potential of novel BODIPY-based nanoparticles for cancer treatment.

Main Methods:

• Synthesis of macrocyclic BODIPY derivatives via alkali-induced cyclization.
• Photophysical characterization including absorption and emission spectroscopy.
• Crystal structure analysis and theoretical calculations (DFT).
• Preparation and characterization of BODIPY-based nanoparticles (7a-NPs).
• In vitro and in vivo evaluation of photothermal therapeutic performance.

Main Results:

• Cyclization significantly decreased the HOMO-LUMO energy gap and increased HOMO energy.
• Macrocyclic BODIPY derivatives showed reduced radiative transitions and enhanced intersystem crossing.
• Compound 7a exhibited a redshifted absorption spectrum with maximum absorption at 794 nm.
• 7a-NPs demonstrated high water solubility, stability, and photothermal conversion efficiency (44.6%).
• In vitro and in vivo studies confirmed efficient tumor accumulation and ablation by 7a-NPs under near-infrared irradiation.

Conclusions:

• Alkali-induced cyclization is an effective strategy to tune the photophysical properties of BODIPY photosensitizers.
• Macrocyclic BODIPY derivatives are promising candidates for efficient photothermal conversion materials.
• 7a-NPs show significant potential for near-infrared photothermal cancer therapy due to their enhanced properties and tumor ablation efficacy.