Russian scientists have developed a biosensor based on the Prussian blue pigment, which determines the levels of glucose and lactate in blood and sweat with an accuracy of 99%. Certain concentrations of these molecules can indicate overwork, as well as diseases such as diabetes and meningitis. The proposed device is compact and easily attached to the surface of the skin, so it can be used for continuous monitoring of the health status of athletes and patients with diabetes. The results of the study, supported by a grant from the Russian Science Foundation (RSF), are published in the journal Sensors and Actuators, B: Chemical.
To monitor the levels of glucose and lactate in the body in real time, there are special sensors. At the same time, they measure the concentration of the corresponding compounds not directly, but fix the number of peroxide molecules formed during their oxidation in the blood. Therefore, the sensors must attach to the blood vessels below the surface of the skin. Scientists are trying to make wearing such devices painless, avoiding damage to the skin and vessel walls.
Scientists experimentally tested the sensitivity of biosensors by placing them in solutions of glucose and lactate of different concentrations. It turned out that at any concentration of these molecules, characteristic of the human body, the device worked stably. Experiments with human blood and sweat samples have shown that the sensor detects glucose and lactate concentrations in both fluids with an accuracy of 99%. The device transmitted readings to a specially developed application on a smartphone using Bluetooth. The sample used in the laboratory displayed the measurement result as an electric current value, however, for the convenience of users, the scientists plan to program it automatically to convert to lactate and glucose values. Thanks to this, a person can easily and quickly obtain data and interpret them even without the participation of a doctor.
In addition, the authors compared the stability of a device based solely on Prussian blue with one whose particles were coated with a protective layer of nickel hexacyanoferrate. The samples had the same sensitivity, but the latter worked up to eight times longer. At the same time, the most stable sensors were based on particles with a size of 50 nanometers, comparable in size to small viruses.