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Published on: May 16, 2022
Morphology-Engineered Gold Nanostars for Activatable NIR-II Imaging of Intracellular miR-21 with Deep Tissue
Lei Zhang1, Yuqin Liao2, Lvyun Zhu3
1Renmin Hospital of Wuhan University, College of Chemistry and Molecular Sciences, Department of Cardiology, Institute of Molecular Medicine, Wuhan University, Wuhan430072, China.
Analytical Chemistry
|August 11, 2026
Summary
This study introduces a novel Near-Infrared II (NIR-II) nanoprobe for detecting low-abundance microRNA-21 (miR-21) in deep tissues. The activatable probe utilizes nanometal surface energy transfer (NSET) for enhanced signal-to-background ratio and deep tissue imaging.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Molecular Imaging
Background:
- Near-infrared II (NIR-II) fluorescence imaging offers deep-tissue visualization but faces challenges with high background noise in conventional probes.
- Existing activatable probes often use visible-light acceptors, limiting efficient signal quenching in the NIR-II window.
Purpose of the Study:
- To develop a generalizable strategy for constructing a NIR-II core-satellite nanoprobe for intracellular miR-21 detection with improved signal-to-background ratio.
- To engineer a nanoprobe utilizing nanometal surface energy transfer (NSET) for precise spectral overlap and efficient fluorescence quenching.
Main Methods:
- Morphology-engineered gold nanostars (AuNSs) were tuned for localized surface plasmon resonance (LSPR) to match the NIR-II emission of Ag2S quantum dots.
- DNA self-assembly guided the creation of AuNS@Ag2S core-satellite structures with controlled interparticle spacing.
- A miR-21-triggered strand displacement reaction was employed to induce probe activation and fluorescence "turn-on".
Main Results:
- The core-satellite nanoprobe achieved up to 88% initial fluorescence quenching efficiency.
- Demonstrated a low detection limit of 75.8 pM for miR-21 with single-base mismatch discrimination.
- Successfully visualized differential miR-21 expression in living cells with high-contrast NIR-II signals at depths up to 15 mm in tissue.
Conclusions:
- Established a novel NSET-based analytical platform for high signal-to-background biosensing in the NIR-II window.
- The engineered nanoprobe provides a robust strategy for in situ analysis of low-abundance miR-21 in deep tissues.
- This approach offers significant potential for advancing deep-tissue molecular imaging and diagnostics.
