Light-sheet microscopy in the near-infrared II window

Area of Science:

• Biomedical optics
• In vivo imaging
• Microscopy

Background:

• Deep-tissue optical imaging in live mammals is limited by light scattering.
• High spatiotemporal resolution is crucial for observing dynamic biological processes.

Purpose of the Study:

• To develop a non-invasive, high-resolution 3D optical imaging method for deep tissues in live mammals.
• To overcome light scattering limitations for enhanced imaging penetration.

Main Methods:

• Near-infrared II (NIR-II) light-sheet microscopy utilizing excitation and emission wavelengths up to 1,320 nm and 1,700 nm, respectively.
• Optical sectioning techniques applied to achieve deep penetration in live tissues and cleared tissues.
• In vivo imaging of live mice using normal and oblique configurations.

Main Results:

• Achieved optical sectioning at ~750 μm penetration depth in live tissues and ~2 mm in cleared brain tissues.
• Enabled non-invasive in vivo imaging through intact mouse tissue, including the intact mouse head.
• Revealed abnormal blood flow and T-cell dynamics in tumor microcirculation.
• Mapped programmed-death ligand 1 and programmed cell death protein 1 in tumors at cellular resolution.
• Resolved vascular channels between the skull and brain cortex and monitored immune cell recruitment to traumatic brain injury sites.

Conclusions:

• NIR-II light-sheet microscopy offers a powerful non-invasive tool for deep-tissue 3D imaging in live mammals.
• This technique provides unprecedented cellular resolution for studying complex biological systems in vivo.
• Applications include tumor microcirculation analysis, immunotherapy target mapping, and neuroinflammation studies.