Engineering Intermolecular Packing of Quinoid-Cyanine Scaffolds for Enhanced Afterglow Brightness and Activatable...

Area of Science:

• Chemical Engineering
• Biomedical Imaging
• Luminescence

Background:

• Afterglow luminescence imaging offers autofluorescence-free, ultrahigh-sensitivity imaging.
• Self-sustaining afterglow molecules (SAMs) simplify systems but suffer from aggregation-caused quenching (ACQ).
• ACQ compromises afterglow signal by suppressing photosensitization and increasing intermolecular interactions.

Purpose of the Study:

• To design novel self-sustaining quinoid-cyanine-based afterglow scaffolds (QCAs) to mitigate ACQ.
• To develop an activatable afterglow probe for in vivo imaging of reactive oxygen species and diseases.
• To enhance afterglow intensity and imaging sensitivity for biomedical applications.

Main Methods:

• Incorporation of steric hindrance groups into quinoid-cyanine scaffolds to suppress intermolecular interactions and ACQ.
• Introduction of a phenylboronic acid moiety for ONOO-activatable afterglow imaging.
• Functionalization with angiopep-2 peptide for blood-brain barrier penetration and disease imaging.

Main Results:

• Engineered QCAs demonstrated a 1566-fold increase in afterglow intensity.
• The probe achieved ultrahigh signal-to-background ratio (SBR) of 426 for in vivo tumor imaging.
• The angiopep-2 functionalized probe differentiated Parkinson's disease models from controls with a contrast of 6.5.

Conclusions:

• A systematic chemical engineering strategy effectively suppresses intermolecular quenching in SAMs.
• The developed QCAs enable activatable afterglow luminescence for advanced bioimaging.
• This approach significantly improves sensitivity and specificity for in vivo disease detection.