Bright, Robust and Readily Accessible Fluorophore Family for NIR-II Bioimaging

Area of Science:

• Materials Science
• Biomedical Engineering
• Organic Chemistry

Background:

• High-performance fluorophores are crucial for near-infrared-II (NIR-II) bioimaging.
• Existing NIR-II dyes face limitations in light absorption, emission efficiency, and synthesis complexity.

Purpose of the Study:

• To develop a novel, highly bright NIR-II dye family using a straightforward synthesis strategy.
• To investigate the optical properties and bioimaging capabilities of the new BM dyes.

Main Methods:

• A 2-step cyclization strategy was employed to synthesize the BM dye family.
• Optical properties, including molar extinction coefficients and fluorescence quantum yields, were characterized.
• In vivo bioimaging of vasculature and lymphatic systems, as well as disease models, was performed.

Main Results:

• The BM dyes possess rigid, coplanar skeletons with superior molar extinction coefficients (up to 3.7 × 10^5 M^-1 cm^-1) and high fluorescence quantum yields (up to 18.4%).
• BM3 was identified as the brightest NIR-II fluorophore reported to date.
• High-resolution in vivo imaging of cerebral vasculature and lymphatic vessels was achieved at ultra-low doses (nmol and pmol levels).
• BM3 enabled detection of cerebral capillary damage and real-time tracking of lymphatic inflammation.

Conclusions:

• The developed BM dye family offers a streamlined approach to synthesizing ultrabright NIR-II fluorophores.
• BM3 represents a significant advancement in NIR-II imaging, offering unprecedented brightness and sensitivity.
• These findings pave the way for enhanced precision in bioimaging, disease diagnostics, and biomedical innovations.