Amphiphilic Chlorin-β-cyclodextrin Conjugates in Photo-Triggered Drug Delivery: The Role of Aggregation

Area of Science:

• Bioconjugate Chemistry
• Photodynamic Therapy
• Nanomedicine

Background:

• Amphiphilic conjugates of chlorins and β-cyclodextrin were synthesized.
• These conjugates exhibit photostability and singlet oxygen generation comparable to clinical standards.
• They form nanoparticles capable of drug loading.

Purpose of the Study:

• To evaluate chlorin-β-cyclodextrin conjugates as drug delivery systems for tamoxifen.
• To investigate the photodynamic activity and cellular uptake mechanisms.
• To assess the potential for photochemical internalization (PCI) of tamoxifen.

Main Methods:

• Synthesis and characterization of chlorin-β-cyclodextrin conjugates.
• Loading of tamoxifen into the conjugates and characterization of loaded nanoparticles.
• In vitro studies using MCF-7 cells, including cellular uptake, dark toxicity, and phototoxicity assays.
• Comparison with porphyrin-β-cyclodextrin conjugates.

Main Results:

• Conjugates formed stable nanoparticles and efficiently loaded tamoxifen.
• Intracellular fluorescence indicated accumulation in endosome/lysosome compartments with no dark toxicity.
• Photodynamic therapy with loaded conjugates achieved 74% cancer cell death via PCI.
• Chlorin conjugates showed less sustained effects compared to porphyrin conjugates.

Conclusions:

• Chlorin-β-cyclodextrin conjugates are promising for photodynamic therapy and tamoxifen delivery.
• Photochemical internalization mechanism was confirmed for tamoxifen release.
• Factors beyond photophysical properties influence in vitro photodynamic system effectiveness.