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MOSCOW, November 23 Russian scientists together with Serbian colleagues have developed a device for relatively quickly detecting heart failure by analyzing the patient’s saliva, reported the Russian Scientific Research Institute fund.
Cardiovascular diseases remain the leading cause of death in the world. To assess the risk of these diseases, a blood test is usually used. One of the markers of heart failure can be the NT-proBNP protein, which is released in large quantities during severe stress (stretch) in myocardial cells and actively enters the blood. A test for this protein has already entered clinical practice, but sometimes taking blood for analysis can be traumatic for the patient — for example, if he is in the intensive care unit and has suffered significant blood loss.
This marker can also be determined by analyzing saliva. But the concentration of NT-proBNP in human saliva is a thousand times lower than in the blood, which means that highly sensitive instruments are needed to accurately measure its amount.
Scientists from the National Research University MIET (Moscow) and the Institute for Research and Development of Information Technologies in Biosystems (Serbia) have developed a highly sensitive sensor based on graphene, a material consisting of just one layer of carbon atoms. Graphene served as a conductor — an element that conducts electric current differently depending on whether the analyzed solution (saliva) contains the NT-proBNP protein. To make the sensor more receptive to the protein, the authors attached a corresponding receptor to graphene — a molecule that can be compared to receptors in the tongue that can recognize substances responsible for a particular taste.
As a result, in the presence of the NT-proBNP protein in the graphene conductor, the electron concentration changed, which could be used to track the marker of heart failure. Scientists needed only two device parameters: conductivity and threshold voltage. Conductivity — the ability of substances to conduct current — is associated with the presence of charge carriers in them. The higher the protein concentration, the more electrons the sample transferred. The threshold voltage is inversely proportional to the electron concentration: if the number of charged particles increased, the voltage dropped. Thus, if these parameters are measured synchronously, the reliability of the analysis increases.
Researchers tested the sensor on artificial saliva. Its chemical composition is similar to natural, but it is more indicative because its properties are easier to control. As a result, the sensor identified the NT-proBNP marker in less than ten minutes. These types of blood serum tests take much longer—approximately 45 minutes.
According to the authors of the work, in the future this test can be used in emergency departments, when it is necessary to quickly determine the possible causes of deterioration in a person’s condition.