Radiodynamic Properties of Liposomes Encapsulating a Bi³⁺ Triple-Decker Phthalocyanine

Area of Science:

• Materials Science
• Radiochemistry
• Oncology

Background:

• Developing effective radiosensitizers is crucial for improving cancer radiotherapy outcomes.
• Porphyrinoids, particularly metallated ones, show promise as radiosensitizers due to their redox properties.
• The efficacy of phthalocyanines as radiosensitizers remains less explored compared to porphyrins and texaphyrins.

Purpose of the Study:

• To design, synthesize, and characterize a novel triple-decker bismuth-phthalocyanine complex (BiTD) for potential use as a radiosensitizer.
• To evaluate the biocompatibility, cellular uptake, and radiosensitizing efficacy of BiTD.
• To investigate the potential of multideck phthalocyanines in enhancing radiodynamic therapy (RDT).

Main Methods:

• Synthesis and characterization of a triple-decker bismuth-phthalocyanine complex (BiTD).
• Encapsulation of BiTD in liposomes to improve biocompatibility and cellular uptake.
• Radiochemical assays to measure reactive oxygen species (ROS) generation upon ionizing radiation.
• Evaluation of BiTD's efficacy in pancreatic cancer spheroids under radiotherapy.

Main Results:

• The synthesized BiTD complex demonstrated excellent stability when encapsulated in liposomes.
• Liposomal BiTD significantly outperformed free phthalocyanines in generating ROS under ionizing radiation.
• BiTD treatment led to improved radiotherapy outcomes in pancreatic cancer spheroids.

Conclusions:

• Bicoordinated multideck phthalocyanines, exemplified by BiTD, represent a promising class of metalloorganic radiosensitizers.
• Liposomal encapsulation enhances the performance of BiTD, suggesting a viable strategy for RDT.
• This study establishes a new molecular design approach for developing effective radiosensitizers and understanding RDT mechanisms.