Scattering oblique plane microscopy for in-vivo blood cell imaging

Area of Science:

• Biomedical Optics
• Microscopy
• In Vivo Imaging

Background:

• Oblique plane microscopy (OPM) offers high-speed volumetric imaging but is limited for *in vivo* human studies due to reliance on fluorescent dyes.
• Label-free imaging is crucial for exploring the *in vivo* potential of OPM in human subjects.

Purpose of the Study:

• To introduce a scattering-contrast oblique plane microscope (sOPM) for label-free *in vivo* imaging of human blood cells.
• To demonstrate the capability of sOPM for analyzing blood cell composition and flow in human capillaries.

Main Methods:

• Developed and utilized a scattering-contrast oblique plane microscope (sOPM) illuminating human capillaries with an oblique light sheet.
• Acquired paired widefield and axial images by synchronizing sOPM with a conventional capillaroscope.
• Performed *in vitro* validation using polystyrene beads and isolated blood cells (red blood cells, white blood cells, platelets) in agar phantoms.

Main Results:

• Successfully demonstrated label-free, *in vivo* imaging of blood cells flowing through human capillaries.
• sOPM images provided insights into the composition of optical absorption gaps between red blood cells.
• Compared scattering-based OPM with fluorescence-based OPM, highlighting technique-specific differences.

Conclusions:

• The scattering-contrast oblique plane microscope (sOPM) represents a significant advancement for label-free *in vivo* human capillary imaging.
• This technology opens new possibilities for *in vivo* blood analysis, potentially aiding in disease diagnosis and monitoring.