Brain photography
The brain was photographed using a surgical needle and a laser
Engineers from the University of Utah have developed a new method for visualizing brain tissue using a microfine surgical needle and laser light.
Imaging deep inside biological tissues, such as the brain, is important for their study, as well as for the diagnosis and treatment of related diseases. Previously, multiphoton microscopy was used for this, based on the capture of photons coming from cells tinted with a special fluorescent dye. The main disadvantage of this method was the small depth of penetration into the object of interest to scientists and physicians. With the help of three-photon microscopy, it was possible to achieve a maximum penetration depth of up to 1.2 mm. But this turned out to be ineffective, since many important areas of the brain, for example, the basal ganglia, hippocampus and hypothalamus, are deeper.
American researchers have developed a new, more advanced way of visualizing biological tissues, which they called computational cannular microscopy. To do this, they used a conventional microfine surgical needle – a cannula – with a diameter of 0.22 mm.
Cannulas. Photo: Dr. Henning Krämer / commons.wikimedia.org
The object of the study was the brain of a three-day-old transgenic mouse. Her microglial cells expressed the bright red fluorescent protein td-Tomato. This was done on purpose, since the new imaging method is based on the excitation of photons of a fluorescent protein by a laser, the light from which passes through the cannula. The laser beam shines through the needle into the brain, illuminating the cells like a flashlight. Photons excited in this way from brain cells are captured by special lenses. The captured light then passes through a specially designed sophisticated algorithm that collects the scattered light waves into a 2D or 3D image. So scientists can get photos and videos of biological tissues.
In this new study, scientists managed to penetrate the brain to a depth of about 2 mm. The distance of 0.8 mm in this case is a big step forward. Thanks to this, it was possible to visualize the microglial cells of the mouse brain well, considering all their characteristic features (such as the absence of protrusions). The new method of tissue visualization may soon find wide application in human research.
A snapshot of brain cells (from the University of Utah engineers press release
can take pictures of the brain with surgical needle and laser light) – VM.
According to scientists, the advantage of the method is not only in the depth of the brain illumination, but also in greater security. "We claim that computational cannular microscopy is able to minimize tissue damage when examining deep areas of the brain due to its small size. At the same time, sufficient resolution, a wide field of vision and the ability to quickly obtain images are achieved. In addition, this method is elegantly simple, since it requires only a cannula and calculations," the researchers summed up their work.
The study was published in the journal Scientific Reports (Kim et al., Deep-brain imaging via epi-fluorescence Computational Cannula Microscopy).
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22.03.2017