Two-photon fluorescence provides insights into blood flow

The development – from the University of Hong Kong in collaboration with the University of California, Berkeley - is expected to provide neuroscientists with a tool to better understand the inner workings of the brain, particularly how blood flow changes at the level of individual blood vessels and across the larger vessel network within the brain. This can help to explain how energy is distributed and regulated in healthy and diseased brains.

The team’s findings have been published in Proceedings of the National Academy of Sciences.

The team’s microscope is said to have super high-speed two-photon fluorescence imaging that penetrates light more deeply into tissue than other gold-standard microscopy technologies to capture blood cells in fast motion. Most other technologies work with one-photon fluorescence and have a slow focus-scanning mechanism, which limits them to capturing low-flow speed regimens in anaesthetised animals.

The two-photon imaging technology developed by the team captures faster moving flows – in this case, red blood cells –when the animals are awake and able to move somewhat. The flow of red blood cells is an important cue of brain activity, which is fuelled by energy from blood supply.