Hierarchically Multifunctional Fiber-optic Theranostic Probe for Cancer Photothermal-photodynamic Synergism.

Area of Science:

• Biomedical Engineering
• Oncology
• Materials Science

Background:

• Photodynamic therapy (PDT) efficacy is limited by poor light penetration and tumor hypoxia.
• Existing theranostic probes face challenges with signal crosstalk and oxygen supply.

Purpose of the Study:

• To develop a multifunctional fiber-optic theranostic probe for enhanced cancer treatment.
• To address hypoxia and improve PDT efficacy through a spatially stratified design.

Main Methods:

• A layered fiber-optic probe incorporating an oxygen sensor (Ru(dpp)), photosensitizer (ICG), and oxygen generator (CaO2@LA).
• Utilized wavelength-dependent evanescent field properties for multi-wavelength activation and signal separation.
• Evaluated in vitro dissolved oxygen sensing and reactive oxygen species (ROS) generation.
• Assessed in vivo antitumor efficacy in a murine model.

Main Results:

• Achieved high-resolution dissolved oxygen (DO) sensing (0.12 mg/L) with a rapid 1s response time.
• Demonstrated effective ROS generation and mitigation of hypoxia-induced PDT limitations.
• Successfully mapped intratumoral hypoxic heterogeneity in vivo.
• Achieved complete tumor growth inhibition through synergistic photothermal-photodynamic therapy (PTT-PDT).

Conclusions:

• The multifunctional probe offers a new paradigm for fiber-optic theranostics in oncology.
• Spatially stratified design prevents crosstalk and enhances therapeutic outcomes.
• Potential for advancing clinical translation of fiber-mediated phototherapies.