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NIR-Triggered "OFF/ON" Photodynamic Therapy through a Upper Critical Solution Temperature Block Copolymer.
Dawei Jiang1, Chao Chen2, Yudong Xue1
1Shanghai Key Laboratory of Functional Materials Chemistry, School of Materials Science and Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 China.
ACS Applied Materials & Interfaces
|September 17, 2019
Summary
This study introduces a novel photothermal activatable photosensitizer (A-PS) for cancer therapy. The A-PS uses a temperature-sensitive polymer that releases its therapeutic effect upon laser activation, enhancing antitumor outcomes.
Area of Science:
- Biomedical Engineering
- Materials Science
- Oncology
Background:
- Activatable photodynamic therapy (A-PDT) offers targeted cancer treatment by producing reactive oxygen species (ROS) at disease sites.
- Thermal responsive polymers, typically with a lower critical solution temperature (LCST), are commonly used in A-PDT systems.
- Existing A-PDT systems face challenges in precise activation and targeted ROS generation.
Purpose of the Study:
- To develop a novel photothermal activatable photosensitizer (A-PS) utilizing an upper critical solution temperature (UCST) polymer.
- To investigate the mechanism of A-PS activation and its efficacy in cancer therapy.
- To explore the potential of UCST-based polymers in designing advanced cancer treatment systems.
Main Methods:
- Fabrication of an amphiphilic block copolymer incorporating porphyrin (TPP) and a cyanine dye (IR780) with a UCST of 42 °C.
- Characterization of the A-PS nanoparticles and their behavior under thermal and laser stimuli.
- In vitro evaluation of A-PS-mediated photodynamic therapy and photothermal therapy on A549 cancer cells.
Main Results:
- The A-PS exhibited an "OFF" state during circulation due to fluorescence resonance energy transfer (FRET) between TPP and IR780, inhibiting photoactivity.
- Upon 808 nm laser irradiation, IR780 efficiently converted light to heat, increasing local temperature above the UCST and dissociating the nanoparticles.
- This dissociation triggered the "ON" state, enhancing porphyrin photoactivity and leading to significant antitumor effects.
- The UCST-based A-PS demonstrated effective photothermal conversion and enhanced therapeutic outcomes.
Conclusions:
- The developed UCST-based A-PS system effectively overcomes the limitations of traditional A-PDT by enabling precise, externally triggered activation.
- The combination of photothermal and photodynamic properties offers a synergistic approach for enhanced cancer therapy.
- This work provides a new strategy for designing smart drug delivery and therapeutic systems for precision medicine.