Optical-resolution photoacoustic microscopy for in vivo imaging of single capillaries

TLDR

Capillaries are the smallest vessels where oxygen and nutrients exchange, and noninvasive imaging of them is essential for studying physiology such as neurovascular coupling, yet existing modalities lack the necessary sensitivity and spatial resolution. The study presents in vivo imaging of the microvasculature, including single capillaries in mice, using optical‑resolution photoacoustic microscopy (OR‑PAM). The authors developed OR‑PAM in their laboratory to image microvasculature in vivo. OR‑PAM achieves a lateral resolution of 5 µm and an imaging depth greater than 0.7 mm.

Abstract

Capillaries, the smallest blood vessels, are the distal end of the vasculature where oxygen and nutrients are exchanged between blood and tissue. Hence, noninvasive imaging of capillaries and function in vivo has long been desired as a window to studying fundamental physiology, such as neurovascular coupling. Existing imaging modalities cannot provide the required sensitivity and spatial resolution. We present in vivo imaging of the microvasculature including single capillaries in mice using optical-resolution photoacoustic microscopy (OR-PAM) developed in our laboratory. OR-PAM provides a lateral resolution of 5 μm and an imaging depth >0.7 mm.