Excited-State Conformational Dynamics Enables Visible-Light-Activated Near-Infrared Phosphorescent Nano-Assemblies
Junru Chen1, Haiyang Wang2, Xiuzhen Liu1
1Matter School of Materials and Energy, Guangdong University of Technology, Guangzhou, P. R. China.
Angewandte Chemie (International Ed. in English)
|July 26, 2026
Summary
Researchers developed a new strategy for visible-light-excited near-infrared ultralong organic phosphorescence (NIR-UOP). Their molecule, py-2mNO2, enables efficient NIR-UOP for high-contrast tumor imaging, even with a phone flashlight.
Area of Science:
- Organic Chemistry
- Materials Science
- Biomedical Imaging
Background:
- Visible-light-excited near-infrared ultralong organic phosphorescence (NIR-UOP) shows promise but faces development challenges.
- Efficient NIR-UOP systems are crucial for advanced imaging applications.
Purpose of the Study:
- To design a rational molecular strategy for achieving visible-light-excited NIR-UOP.
- To develop efficient NIR-UOP nanoparticles for in vivo imaging of hypoxic tumors.
Main Methods:
- Molecular design focusing on excited-state conformational dynamics.
- Synthesis and characterization of the optimized molecule, py-2mNO2.
- Assembly of py-2mNO2 nanoparticles using a polymethyl methacrylate (PMMA) isolation strategy.
Main Results:
- The molecule py-2mNO2 exhibits NIR-UOP emission at 635 and 700 nm with a long lifetime (268 ms).
- Dynamic conformational charge transfer enhances intersystem crossing (ISC).
- Matrix-isolated nanoparticles achieved high-contrast hypoxic tumor imaging (SBR = 39.47), excitable by a phone flashlight (SBR = 14.55).
Conclusions:
- A rational design strategy for visible-light-excited NIR-UOP systems was established.
- An efficient nano-assembly approach for NIR-UOP nanoparticles suitable for in vivo imaging was demonstrated.
- This work advances NIR-UOP technology for biomedical applications.
