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Updated: Jan 14, 2026
A Bright NIR-II Fluorescence Probe for Vascular and Tumor Imaging
Published on: March 17, 2023
Dually quenched and targeting nanoprobe for sensitive and specific fluorescence imaging of tumor
Guowei Liang1, Tiantian Xia1, Jingyang Huang2
1State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 211189, China.
Abstract:
Fibroblast activation protein α (FAPα) is crucial in tumor progression, making it an attractive target for cancer diagnosis. However, existing FAPα fluorescence probes are predominantly small-molecule agents with limited sensitivity and specificity. To address this, we developed NIR-CBT-NP, an activatable "turn-on" nanoprobe featuring dual-quenched fluorescence and dual-targeting capability for highly sensitive and specific FAPα imaging. NIR-CBT-NP, synthesized through reduction-controlled CBT-Cys click reaction by Cys(StBu)-Gly-Pro-Ala-His-Lys(IR780)-CBT (NIR-CBT), achieves efficient fluorescence "off" via intramolecular and intermolecular quenching. After administration, NIR-CBT-NP accumulates in tumors via the enhanced permeability and retention effect and is specifically activated by FAPα to turn the fluorescence "on". Compared to that of FAPα-inhibited control, it shows 13.0-, 3.0-, or 4.3-fold signal enhancement in vitro, in FAPα-overexpressing MIA PaCa-2 cells, or in tumor-bearing mice, respectively. In vivo studies confirm its superior tumor targeting, prolonged retention, and excellent biosafety. These findings establish NIR-CBT-NP as a powerful tool for possible early detection of the FAPα-expressing tumors.
Insights
We developed NIR-CBT-NP, a novel nanoprobe for highly sensitive and specific imaging of fibroblast activation protein α (FAPα). This "turn-on" probe enables enhanced tumor detection and potential early cancer diagnosis.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Cancer Imaging
Background:
- Fibroblast activation protein α (FAPα) is a key target in cancer progression and diagnosis.
- Existing FAPα fluorescence probes often lack sufficient sensitivity and specificity.
- Small-molecule probes face limitations in clinical applicability.
Purpose of the Study:
- To develop an activatable "turn-on" nanoprobe for highly sensitive and specific FAPα imaging.
- To overcome the limitations of current small-molecule FAPα fluorescence probes.
- To enable advanced cancer diagnosis through improved FAPα detection.
Main Methods:
- Synthesis of NIR-CBT-NP via reduction-controlled CBT-Cys click reaction.
- Utilizing dual-quenched fluorescence and dual-targeting strategies.
- Evaluating probe performance in vitro, in FAPα-overexpressing cells, and in tumor-bearing mice.
Main Results:
- NIR-CBT-NP demonstrated efficient fluorescence "off" state due to dual quenching.
- Tumor accumulation via enhanced permeability and retention effect observed.
- Significant signal enhancement (13.0-fold in vitro, 3.0-fold in cells, 4.3-fold in vivo) upon FAPα activation.
- Superior tumor targeting, prolonged retention, and excellent biosafety confirmed in vivo.
Conclusions:
- NIR-CBT-NP represents a significant advancement in FAPα-targeted imaging.
- The nanoprobe offers high sensitivity and specificity for FAPα detection.
- This technology holds promise for the early detection of FAPα-expressing tumors.
