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Updated: Jan 9, 2026
Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers
Published on: October 28, 2015
Analysis of ROS dynamics based on dissolved oxygen sensing in upconversion nanoparticle-based photodynamic therapy
Esmaeil Heydari1, Sepideh Delavari2, Motahareh Jafarpour2
1Nanophotonic Sensors and Optofluidics Lab, Faculty of Physics, Kharazmi University, Tehran 15719-14911, Iran; Center for International Scientific Studies & Collaborations (CISSC), Ministry of Science Research and Technology of Iran, Tehran, Iran.
This study quantifies the contributions of upconversion nanoparticles (UCNPs), Rose Bengal (RB) photosensitizer, and culture medium to reactive oxygen species (ROS) generation in photodynamic therapy (PDT). Real-time monitoring using a novel sensor optimizes UCNP-based PDT for cancer treatment.
Area of Science:
- Nanotechnology and Biomedical Engineering
- Photochemistry and Photophysics
- Cancer Therapeutics
Background:
- Photodynamic therapy (PDT) utilizes reactive oxygen species (ROS) for cancer cell elimination.
- Upconversion nanoparticles (UCNPs) enable near-infrared (NIR) light activation, improving tissue penetration for PDT.
- Real-time monitoring of ROS dynamics is crucial for optimizing PDT but is challenging with conventional methods.
Purpose of the Study:
- To quantitatively assess the individual contributions of UCNPs, photosensitizer (RB), and culture medium to ROS generation in UCNP-based PDT.
- To introduce novel metrics (medium activation time, maximum PL lifetime change, time to maximum PL lifetime change) for real-time ROS analysis.
- To optimize UCNP and RB concentrations for enhanced in-vitro PDT efficacy.
Main Methods:
- Development and implementation of a 3D-printed optofluidic dissolved oxygen (DO) sensor for indirect ROS detection via photoluminescence (PL) lifetime changes.
- MTT assays to determine optimal concentrations of NaYF4:Yb3+,Tm3+ UCNPs and Rose Bengal (RB) photosensitizer using A375 melanoma cells.
- In-vitro PDT experiments utilizing a 980 nm NIR laser for UCNP activation and real-time ROS monitoring.
Main Results:
- UCNPs, RB, and cell culture medium contributed approximately 25%, 26%, and 4% to the total photoluminescence lifetime change (Δτ), respectively.
- Maximum PDT performance was achieved with the combined presence and activation of all components, leading to the highest ROS levels.
- Laser excitation of the medium or UCNPs alone (without RB) induced partial ROS generation, highlighting their inherent roles.
Conclusions:
- The study successfully quantified the relative contributions of key components in UCNP-based PDT using a novel real-time ROS monitoring approach.
- The findings provide critical insights for refining UCNP-based PDT strategies and optimizing photosensitizer formulations for improved cancer treatment.
- The developed optofluidic sensor and introduced metrics offer a powerful tool for mechanistic studies and therapeutic optimization in PDT.
