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Updated: Jul 16, 2026
A Bright NIR-II Fluorescence Probe for Vascular and Tumor Imaging
Published on: March 17, 2023
An Activatable Ratiometric Photoacoustic/Near-Infrared-II Fluorescence Dual-Modal Probe for in vivo Imaging of pH
Jiahao Zhao1, Di Liu1, Qiang Tong1
1State Key Laboratory of Flexible Electronics (LoFE), Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), School of Materials Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing210023, China.
A novel pH-sensitive molecular probe, 5-HP-IR, enables sensitive and specific in vivo imaging of tumor acidity using dual photoacoustic and near-infrared-II fluorescence modalities for improved cancer diagnosis.
Area of Science:
- Biomedical Imaging
- Molecular Probes
- Cancer Diagnostics
Background:
- Tumor acidity is a critical factor in cancer progression, influencing diagnosis and treatment.
- Current methods for visualizing and quantifying tumor acidity in vivo lack sensitivity and specificity.
- Developing advanced molecular probes is essential for accurate tumor microenvironment characterization.
Purpose of the Study:
- To develop and validate a novel pH-sensitive dual-modal molecular probe for in vivo imaging of tumor acidity.
- To integrate ratiometric photoacoustic (PA) and near-infrared-II (NIR-II) fluorescence (FL) imaging into a single small-molecule scaffold.
- To enhance diagnostic reliability and sensitivity for tumor acidity detection.
Main Methods:
- Design of a small-molecule probe (5-HP-IR) incorporating an NIR-II organic dye and a pH-responsive piperazine moiety.
- Evaluation of probe performance across a range of pH values, measuring changes in PA and NIR-II FL signals.
- In vivo imaging studies to assess the probe's ability to visualize and quantify tumor-associated acidity.
Main Results:
- The 5-HP-IR probe exhibited a significant ratiometric increase in PA signals (34.5-fold) and a substantial activation of NIR-II FL signals (174-fold) under acidic conditions.
- Dual-modal imaging provided built-in cross-validation, enhancing diagnostic reliability.
- The probe demonstrated high sensitivity and specificity for detecting tumor acidity in vivo without requiring an internal reference.
Conclusions:
- The 5-HP-IR probe represents a significant advancement in molecular imaging for tumor acidity.
- Its dual-modal capability offers noninvasive, real-time imaging and precise quantification of the tumor microenvironment.
- This molecular platform holds promise for improved cancer diagnosis and personalized treatment strategies.
