Visible spectrum extended-focus optical coherence microscopy for label-free sub-cellular tomography

Area of Science:

• Biomedical Optics
• Microscopy
• Neuroscience Imaging

Background:

• Fourier domain optical coherence microscopy (OCM) offers high-resolution imaging.
• Achieving extended depth of field while maintaining submicron resolution is challenging.

Purpose of the Study:

• To develop an extended-focus optical coherence microscope (OCM) with submicron resolution over a significant depth.
• To demonstrate the capability of the developed system for high-resolution imaging of biological samples, including brain tissue.

Main Methods:

• Utilized an ultra-broad spectrum supercontinuum laser source (240 nm bandwidth) spanning near-infrared to visible wavelengths.
• Integrated the broad spectrum source with a high numerical aperture (NA) objective to achieve isotropic 3D submicron resolution.
• Analyzed imaging performance using microbead samples and applied the system to cell cultures and ex-vivo mouse brain tissue.

Main Results:

• Achieved 0.7 μm axial and 0.4 μm lateral resolution maintained over a 40 μm depth.
• Demonstrated visualization of neuronal cell bodies, fibers, plaques, fine vascular structures, and sub-cellular features in brain tissue.
• Observed sub-cellular structures in live cells, enhanced by a protocol used for OCT angiography.

Conclusions:

• The developed visible light optical coherence microscope (visOCM) provides high-resolution, extended-depth imaging.
• visOCM is effective for detailed visualization of complex biological structures in various tissue types.
• The system shows potential for advanced research in neuroscience and cell biology.