Two-step upconversion-driven PDT/CDT cooperative phototherapeutic platform based on surface magnetic field modulation

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Photochemistry

Background:

• Photodynamic therapy (PDT) uses photosensitizers to generate reactive oxygen species (ROS) for cancer treatment.
• Deep tissue penetration limits PDT efficacy due to visible light absorption by biological tissues.
• Combining PDT with other therapies can overcome limitations and improve anticancer outcomes.

Purpose of the Study:

• To develop an upconversion-driven PDT combined with chemodynamic therapy (CDT) for enhanced deep-tissue cancer treatment.
• To investigate the synergistic effects of UCNP@SiO2@Fe3O4@MC540 nanoparticles in vitro and in vivo.
• To understand the underlying mechanisms of enhanced phototherapeutic effects using FDTD simulations.

Main Methods:

• Synthesis and characterization of UCNP@SiO2@Fe3O4@MC540 nanoparticles.
• Upconversion-driven PDT activation using a 980 nm laser to generate ROS.
• Fe3O4-mediated CDT via Fenton reaction in acidic tumor microenvironments to produce hydroxyl radicals (·OH).
• In vitro and in vivo anticancer efficacy assessments.
• Finite Difference Time Domain (FDTD) simulations to analyze light-matter interactions.

Main Results:

• The UCNP@SiO2@Fe3O4@MC540 system successfully generated ROS and ·OH for dual-therapy.
• Magnetic field modulation enhanced ROS production.
• The combined therapy demonstrated significant in vitro and in vivo anticancer efficacy.
• FDTD simulations confirmed enhanced light absorption and surface electric field contributing to therapeutic effects.

Conclusions:

• The developed upconversion-driven PDT combined with CDT offers a promising strategy for deep-tissue cancer therapy.
• The synergistic action of ROS and ·OH generation significantly boosts anticancer efficacy.
• This study provides insights into optimizing phototherapeutic processes for improved clinical translation.