The device is an artificial pancreas and it will consist of two parts. One part, according to the developers' idea, is slightly larger than a watch battery and can be implanted under the skin near the waist. The other part, the size of a cigarette pack, will be attached outside the body.

Researchers have been trying to produce an artificial pancreas for about twenty-five years with varying success. Research by St. Petersburg physicists promises a significant breakthrough.

“The essence of our method is that it allows to identify glucose and to determine its concentration against a background of multiple other components of blood - by the glucose two-dimensional spectral image, says Vladimir Chuvashov, Ph. D. (Engineering), manager of research. That is, the method allows to measure the glucose content in parallel in one beam by two ways - both by the spectroscopic and the polarimetric ones.

“Practically all earlier developments are based on one-dimensional spectral images. The difference in quality of glucose recognition is approximately the same as between one-dimensional and two-dimensional dactyloscopic skin print in the course of person identification. The method we are developing can be used for glucose identification both in the ophthalmic fluid (this is a non-invasive option) and in the corporeal one (implantable option)”.

In the second case, measurement takes place in the part of the device that is under the skin. It is connected with the help of the optical communications fiber line with the external part where a semiconductor laser is located along with micro-devices for analysis of the signal obtained in the course of the analysis.

So, a small laser generates irradiation. The laser beam is directed under the skin along the optical fiber, i.e. part of glass fiber. The beam is partly absorbed, partly dispersed, and partly reflected. The important thing is that glucose (due to structure of its molecules) changes the beam parameters to some extent. Firstly, it changes the plane of optical polarization, and it is known to what extent. Secondly, it changes intensity of scattered radiation proportionally to the properties inherent in glucose (physicists specify - “due to fundamental absorption bands caused by vibration frequency of a glucose molecule”).

The light which has changed as a result of interaction with the tissue and substances dissolved in intercellular fluid, returns back to the device again along the waveguide. The beam should be analyzed there, so that in the long run a person could determine the glucose concentration in this fluid. To this end, respective devices - spectrometers - are required. Large spectrometers are no problem for a long time, they have been well-known for long. It is difficult to design small ones - so that it would be convenient to carry them all the time.

There are multiple private companies worldwide that deal with similar developments on a competitive basis, and many technical solutions are already known. Detailed development is certainly necessary anyway, but this problem is solvable, and researchers already know the way to solve it.

Further information:
V.D. Chuvashov, Ph.D. (Engineering), principal research assistant
E-mail: chips41@mail.ru ; chips41@soi.spb.ru
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