Scientists from the U.S. and Switzerland have created a glue to the skin of the hands a device that can measure the level of vitamin C in sweat, which correlated with the blood level. Article published in the journal ACS Sensors.
The concentration of substances in the body is usually determined by a blood test. This is a qualitative method, but it is invasive, so it is inconvenient to use for routine measurement of levels of substances, and this is usually done only with the patients for whom it is really necessary (e.g. in diabetes). But the level of many substances in the blood correlated with levels in other fluids, including tears and sweat. In the last few years due to the development of materials and technologies, scientists began to create prototypes of wearable sensors substances-biomarkers in these fluids, e.g., glucose sensorembedded in a contact lens, or sensor to monitor the concentration of cortisol in sweat.
The American-Swiss team led by Joseph Wang (Joseph Wang), University of California at San Diego used this approach in the sensor, concentration of vitamin C. the Sensor allows without a blood test to monitor the level of this substance and maintain it in the normal range.
Scientists chose one of the standard layouts for such devices in which the sensor contains an enzyme that promotes oxidation of the target substance (vitamin C in this study), and measures the change of current occurring due to the reaction. In this case, they put on one of the electrodes of the sensor enzyme exorbitances. It acts as a catalyst, thanks to which reaching the sensor molecule of vitamin C reacts with oxygen. The sensor measures the concentration of vitamin C, not directly, but monitoring the current change of oxygen reduction. It arises from the fact that when the concentration of molecules of vitamin of the oxygen is consumed for oxidation.