Super-resolution functional photoacoustic microscopy via label-free cell tracking

Area of Science:

• Biomedical optics
• Microcirculation research
• Vascular biology

Background:

• Microvascular function and oxygen metabolism are critical for tissue health.
• Existing label-free imaging methods lack the resolution to track single red blood cells (RBCs) in 3D microvascular networks.
• There is a need for advanced imaging techniques to study in vivo oxygen dynamics at the cellular level.

Purpose of the Study:

• To introduce a novel super-resolution functional photoacoustic microscopy (SR-fPAM) technique.
• To enable label-free, spatiotemporal tracking of RBCs and their oxygenation in 3D.
• To provide high-resolution imaging of microvascular networks and oxygen transport.

Main Methods:

• Developed SR-fPAM utilizing dual-wavelength excitation to track RBC movements.
• Achieved super-resolution 3D microvascular architecture reconstruction.
• Quantitatively measured RBC flow and blood oxygenation in vivo.

Main Results:

• SR-fPAM reconstructed 3D microvascular networks with resolution comparable to two-photon microscopy.
• The technique successfully quantified RBC flow and oxygenation dynamics.
• Observed redistribution of oxygen and hemodynamics in 3D microvascular networks following a stroke in live mice.

Conclusions:

• SR-fPAM is an enabling tool for imaging oxygen dynamics in 3D microvascular networks at the single-RBC level.
• This technology bridges a critical gap in oxygen-metabolism imaging.
• Opens new avenues for studying microvascular health, disease, and oxygen transport with enhanced functional insights.