To use an optical fiber thinner than a human hair to look inside the human brain. This is the ambition of the scientific team, which also involves Miroslav Stibůrek, a PhD student of the Faculty of Mechanical Engineering. The so-called holographic micro-endoscopy is currently being tested on mice, but in the future the team would like this tissue-friendly and extremely detailed imaging method to be made available for use in human patients.

Many people are familiar with endoscopic examinations, such as of the esophagus or intestines, where a catheter equipped with a camera and other instruments gets inserted into the body. This type of examination is not very pleasant, though. In the future, patients could be relieved by using smaller fiber optic probes. A team of experts of the Institute of Scientific Instruments of the Academy of Sciences, including Miroslav Stibůrek, a doctoral student of the Faculty of Mechanical Engineering of BUT and a graduate of the Faculty of Electrical Engineering and Communication, are working on development of such probes. This year, Stibůrek received an internal BUT grant for young scientists, the so-called KInG, for the research of the use of optical fibers in imaging the human brain.

"People know about optical fibers mainly thanks to their use in the fast Internet. We are able to use a single optical fiber, which is as thick as a human hair, to image structures inside living tissues. This all is done in submicron resolution, so we can see down to the level of cell organelles," says Stibůrek.

Compared to existing methods of brain examination, optical fibers offer a much more detailed view into any depth of tissue, which today's devices such as CT or tomography are not able to achieve. "Today, it is always a quid pro quo: in case we are able to image tissues at any depth, we lose the ability to see details as the resolution of the devices is in the order of millimeters. With light microscopic methods, we get great resolution, nevertheless we cannot dive too deep. With holographic micro-endoscopy we can achieve any depth with resolution comparable to light microscopy," adds Stibůrek.

In practice, the use of optical fibers could bring relief to patients because it represents a minimally invasive method. Scientists are already testing the technology in the laboratory, but the way to patients – as with all new medical discoveries – will take a while. So far, they are conducting experiments on mice. "The vet puts the fluorescently labeled mouse to sleep, shaves off the hair on its head under anesthesia, cuts the skin and drills a small hole called a cranial window in the skull. Then, this opening is used to introduce the optical fiber into the brain," says Stibůrek, who devoted his doctoral studies to the development of a holographic micro-endoscope.

He is engaged in research in the team of Professor Tomáš Čižmár at the Academy of Sciences. This year, he received a half-million grant from BUT for young doctoral students, thanks to which he can devote a year to the research into the process of optical fiber preparation. "It is not enough for us to just cut the fiber and insert it into the brain. We cover the fiber with various layers of metals and polymers with a thickness of several units to hundreds of nanometers. My work this year is going to focus on this process of preparation," explains Stibůrek who believes that in the future, the research could also turn into a start-up that would help market the promising technology and bring it to hospitals.

"I enjoy the complexity of our research: it involves technology and natural sciences, laboratory experiments and all the data processing. I wish the use of optical fibers to continue to develop and eventually to find application in clinical practice," concludes the young scientist.