Device for Fundamental Research in Physiology Developed at LETI

Device for Fundamental Research in Physiology Developed at LETI

Scientists from LETI and the Institute of Experimental Medicine developed a prototype of a high-precision instrument for measuring rapid fluctuations in human skin temperature based on an original circuit solution on a miniature semiconductor diode sensor.

20.01.2022 352

The microcirculatory bed is a part of the vascular system in which diseases such as atherosclerosis, diabetes, cancer, renal dysfunction, and other pathologies are manifesting in the initial stages. Therefore, in modern clinical practice, assessment of the state of blood microcirculation (movement of blood in capillaries and adjacent microvessels) and evaluation of microcirculatory disorders in the diagnosis of a variety of diseases are relevant.

Scientists all over the world develop and improve tools for reliable and non-invasive monitoring of blood flow in different parts of the body under various conditions and systems capable of recording all vascular elements of the bloodstream – arterial, capillary, and venous components. The physiological activity causes changes in the body surface temperature in a wide amplitude and frequency range that is associated with heartbeat pulsations which have a ridiculously small amplitude and a maximum frequency of temperature oscillations. One of the relevant research areas is related to the development of methods and tools for studying blood flow oscillations based on the results of skin surface thermometry.

Researchers of LETI and their colleagues from the Institute of Experimental Medicine set the goal to develop technical solutions aimed at achieving maximum resolution and high operational properties of a medical thermometer. The research team is headed by Oleg Markelov, Head of the "Perspective Wireless Technologies" area at LETI. The main developer is Alexey Anisimov, a young scientist, Assistant Professor of the Department of Bioengineering Systems.

The prototype proposed by LETI scientists is based on the technology of achieving the required thermal time constant of temperature using a semiconductor diode sensor in an open-frame design. The need for high resolution in a relatively wide operating temperature range, typical for the surface of the human body, determined one of the basic requirements for the thermometer—the possibility of automatic adjustment of its parameters, such as gain and operating point position. The proposed design of the thermostat works on Peltier elements for calibration and calculation of absolute temperature values.

"To carry out laboratory research of the proposed solution, we designed an experimental setup including an original wireless device for recording temperature variations and a recorder of physiological signals made by Biopac for synchronous recording of electrocardiogram and pulse signals. The results obtained have shown that the design approach allows investigating blood microcirculation."

Oleg Markelov, Head of the "Perspective Wireless Technologies" area at LETI

As a result of the work, researchers built, tested, and patented the biomedical thermometer. The ultimate goal of the project is to develop scientifically grounded recommendations for its practical application as a unique method of diagnostics of the human condition and estimation of functional capabilities of the human organism. The obtained results will serve as a basis for the development of new methods of functional diagnostics and professional selection.