Ural Federal University: UrFU Scientists Create a Method For Easier and Cheaper Blood Glucose Concentration Measuring

Scientists at Ural Federal University solved the problem of synthesizing enzyme-free catalysts for more accurate and less expensive determination of blood glucose concentration. The proposed solution lies in the joint layer-by-layer electrochemical deposition of palladium and silver on the surface of the electrode (test strip). The co-authors published an article about the work in the Russian Chemical Bulletin. This is the first description in the scientific literature of the method of layer-by-layer deposition of palladium and silver.

“We used a printed electrode for deposition – a miniature substrate with a suspension of multi-walled, that is, carbon nanotubes embedded in each other. Water from the suspension applied to the electrode evaporates, and the nanotubes remain on the electrode, thus increasing its specific surface area. Then we deposited first silver and then palladium on the modified electrode surface several times alternately,” says Andrei Okhokhonin, associate professor of analytical chemistry at Ural Federal University and head of the research group.

The authors suggested an innovative method of layer-by-layer deposition of silver and palladium. The electrode is dipped alternately in solutions of silver salt AgNO3 and palladium salt K2PdCl4 in dilute sulfuric acid. In this form, the silver and palladium lack one and two electrons, respectively, before they become insoluble metal state. By placing the electrode in the solution, an electric current is applied to it. The current reduces the metals, and this leads to the formation of solid particles on the surface of the electrode. The operation is repeated four times.

“Such a technique has not yet been used, it proved to be effective. The new material has significant catalytic activity in the electrochemical oxidation of glucose. Moreover, unlike analogues, the oxidation reaction efficiently proceeds in neutral phosphate buffer solution medium, which corresponds to the acidity of human blood. Other similar systems are either markedly less sensitive to glucose or work in an alkaline environment and involve an additional step of blood sample dilution, in certain cases by a thousand times. All this complicates procedures and reduces the reliability of analysis results,” emphasizes Andrei Okhokhonin.

According to the developers, the unique characteristics of the obtained system open up broad prospects for its practical application in creating an enzyme-free electrocatalytic sensor for determining glucose in whole blood. The research was supported by the Russian Science Foundation (Project № 20-13-00142).