NIR-II fluorescence in vivo confocal microscopy with aggregation-induced emission dots

Area of Science:

• Biomedical Optics
• Fluorescence Microscopy
• Bioimaging

Background:

• Reduced light scattering in the second near-infrared (NIR-II) window (1,000-1,700 nm) enables deeper in vivo bioimaging.
• Conventional NIR-II bioimaging often uses wide-field illumination and 2D detection, limiting spatial resolution due to out-of-focus signals.

Purpose of the Study:

• To develop a NIR-II fluorescence confocal microscopic system for high-spatial resolution deep tissue imaging.
• To demonstrate the system's capability for in vivo cerebrovascular imaging and lifetime imaging.

Main Methods:

• Setup of a NIR-II fluorescence confocal microscopic system.
• Utilized aggregation-induced emission (AIE) dots as NIR-II fluorescent probes.
• Incorporated time-correlated single photon counting (TCSPC) and femtosecond laser excitation.

Main Results:

• Achieved 800 µm deep 3D in vivo cerebrovascular imaging in mice.
• Obtained a spatial resolution of 8.78 µm at a depth of 700 µm.
• Successfully performed in vivo confocal NIR-II fluorescence lifetime microscopic imaging (FLIM) of mouse cerebral vasculature.

Conclusions:

• NIR-II fluorescence confocal microscopy offers superior spatial resolution for deep tissue bioimaging compared to wide-field methods.
• The developed system enables high-resolution 3D vascular imaging and FLIM in vivo.
• This technology holds promise for advancing in vivo diagnostic and research applications.