Using the method of laser interference microscopy (LIM), the scientists of the Moscow State University named after MV Lomonosov Moscow State University and the All-Russian Research Institute of Optical and Physical Measurements of the RAS have developed approaches to the detailed assessment of the living nerve cells. They were able to measure different parts of the large neuronal processes — the axon.
Details of the research specialists presented at the V International Conference "Recent advances bionanoscopy", held in Moscow on June 15-17.
This work is very important from the point of view of methodology, as it gives researchers a tool for the study of living tissues and cells.
Most modern microscopy techniques require fixation and staining of the biological object, which often leads to distortion of the native structure of the object and, as a consequence, distortion of the received information. The proposed new method — an attempt to get closer to that to see the real picture of what is happening in the living cell. In addition, in this study, which was carried out under the supervision of AI Yusipovich, used devices made by Russian developers: automated interference microprofilometer was established at the Institute VNIIOFI in Moscow on the basis of micro-interferometer MII-4 Linnik (LOMO, Russia).
The basic principle used in the investigation of objects by LIM, — measurement of optical properties, and the environment, as well as the height of the object at the measuring point. Measurements of the "width" of the object correspond to that of conventional optical microscopes, but the "height" of the object is measured much more accurately. LIM can achieve accuracy "vertical" — 2.5 nanometer.
A nerve cell has many branches. Axon, the longest of them can reach in large vertebrates length of one meter or more. Outside, he is roll, covered with myelin fibers formed by wrapping multiple outgrowth of the membrane so-called Schwann cells. But this cover is divided, and sometimes interrupted, forming a so-called nodes of Ranvier, which play a very important role in the transmission of nerve impulses.
With the help of LIM scientists were able to estimate the diameter of the nerve fiber and the diameter of the axon in the nodes of Ranvier, the length of the node of Ranvier and areas in between.
In the region where the contribution of myelin fibers maximum thickness (edge interval axon myelin coating), the measurement accuracy is approximately 40 nanometers. In the node of Ranvier, where the minimum fraction of the membranes, the accuracy of the method — about 300 nanometers. In other parts of the nerve fiber accuracy of the method will vary depending on the proportion of myelin.
Thus, according to scientists, the method allows a fairly accurate assessment of the geometry and the functional state of the nerve fibers.