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Updated: Jun 12, 2025
A Bright NIR-II Fluorescence Probe for Vascular and Tumor Imaging
Published on: March 17, 2023
Multifunctional Organelle-Targeting Probes for Intracellular Imaging and Enhanced Cancer Phototherapy
Weijun Ma1,2, Chen Xie1, Xiaomin Li1
1Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong Special Administrative Region of China.
Abstract:
Photodynamic therapy (PDT) represents a promising modality for cancer treatment; however, its clinical application is hindered by challenges such as glutathione (GSH)-mediated quenching of reactive oxygen species (ROS) and autofluorescence interference during visible light imaging. This study introduces Cy-NBD-5F, a photosensitizer engineered to address these limitations. Upon activation by GSH, Cy-NBD-5F exhibits 5.5-fold fluorescence enhancement at 701 nm, producing its reduced form, Cy-OH-5F, which demonstrates enhanced ROS generation, including a 1.4-fold increase in singlet oxygen and 1.2-fold increase in superoxide anion radicals. Under light irradiation, Cy-OH-5F induces significant cytotoxicity (IC50 < 3 µM). Additionally, the molecule predominantly localizes within lysosomes and the endoplasmic reticulum, showing organelle-specific effects to improve therapeutic efficacy. These findings show the potential of Cy-NBD-5F as a precise and effective tool for cancer theranostics.
Insights
This study introduces Cy-NBD-5F, a novel photosensitizer that overcomes glutathione quenching and autofluorescence in photodynamic therapy (PDT). It enhances reactive oxygen species (ROS) generation for effective cancer theranostics.
Area of Science:
- Biochemistry
- Medical Imaging
- Oncology
Background:
- Photodynamic therapy (PDT) shows promise for cancer treatment but faces challenges like glutathione (GSH)-mediated quenching of reactive oxygen species (ROS) and autofluorescence.
- Existing photosensitizers often struggle with efficiency and specificity in complex biological environments.
Purpose of the Study:
- To develop and evaluate a novel photosensitizer, Cy-NBD-5F, designed to overcome limitations in current PDT applications.
- To assess its performance in terms of fluorescence enhancement, ROS generation, cytotoxicity, and organelle-specific localization.
Main Methods:
- Synthesis and characterization of the Cy-NBD-5F photosensitizer.
- In vitro assessment of GSH-activated fluorescence enhancement and ROS production (singlet oxygen, superoxide anion radicals).
- Evaluation of cytotoxicity and cellular localization (lysosomes, endoplasmic reticulum) under light irradiation.
Main Results:
- Cy-NBD-5F demonstrated a 5.5-fold fluorescence enhancement at 701 nm upon GSH activation, yielding Cy-OH-5F.
- Cy-OH-5F showed increased ROS generation (1.4-fold singlet oxygen, 1.2-fold superoxide anion radicals).
- Significant cytotoxicity (IC50 < 3 μM) was observed under light irradiation, with preferential localization in lysosomes and ER.
Conclusions:
- Cy-NBD-5F effectively addresses GSH-mediated quenching and autofluorescence, enhancing PDT efficacy.
- The photosensitizer exhibits potent ROS generation and targeted organelle effects, improving therapeutic outcomes.
- Cy-NBD-5F holds potential as a precise and effective theranostic agent for cancer treatment.
