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Achieving Ultrabright NIR-II Nanofluorophore for In Vivo Imaging by Inhibiting H-Aggregates Formation
Xialian Tang1, Jiabao Xiong2, Liying Chen1
1Key Laboratory of Flexible Electronics (KLOFE) &, Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211800, China.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|December 23, 2024
Summary
Researchers developed PF8CN, a novel small molecule for Near-Infrared II (NIR-II) fluorescence imaging. Its twisted structure prevents aggregation, significantly boosting fluorescence quantum yield and brightness for enhanced real-time imaging applications.
Area of Science:
- Materials Science
- Organic Chemistry
- Biomedical Imaging
Background:
- Small molecules with acceptor-donor-acceptor (A-D-A) structures are promising for Near-Infrared II (NIR-II) fluorophores due to their optical properties.
- Planar conformations in A-D-A molecules lead to H-aggregate formation, reducing fluorescence quantum yield (QY) in nanofluorophores.
- Developing NIR-II fluorophores with high QY and brightness is crucial for advanced biomedical imaging.
Purpose of the Study:
- To design and synthesize a novel small molecule (PF8CN) with a twisted conformation to inhibit H-aggregate formation.
- To enhance the NIR-II fluorescence quantum yield and brightness of resulting nanofluorophores.
- To demonstrate the utility of PF8CN nanoparticles (NPs) for long-term, real-time NIR-II fluorescence imaging.
Main Methods:
- Synthesized PF8CN, a small molecule featuring terminal 3,5-bis(octyloxy)phenyl groups to induce a twisted molecular conformation.
- Formed PF8CN nanoparticles (NPs) and compared their optical properties (QY, brightness) to a model H-aggregate-forming nanofluorophore (F8CN NPs) and indocyanine green (ICG).
- Utilized PF8CN NPs for in vivo NIR-II fluorescence imaging of cerebral and hindlimb vasculature and thrombolysis.
Main Results:
- PF8CN NPs exhibited a twisted conformation, effectively preventing H-aggregate formation.
- The NIR-II fluorescence QY of PF8CN NPs was 3.8 times higher than F8CN NPs.
- PF8CN NPs demonstrated 5.3-fold and 14.9-fold higher NIR-II brightness than F8CN NPs and ICG/FBS, respectively, at equal molar concentrations.
Conclusions:
- The twisted terminal units of PF8CN successfully inhibit H-aggregation, leading to significantly enhanced NIR-II fluorescence QY and brightness.
- PF8CN NPs are highly suitable for long-term, real-time NIR-II imaging, outperforming existing nanofluorophores.
- This study presents an effective strategy for developing ultra-bright NIR-II nanofluorophores for advanced biomedical applications.
