Glucose biosensors - state of the art and prospects

Rapid glucose concentration detection in technical and biological systems is an important scientific and technical task of modern chemistry, engineering and technology. The article provides an overview of the last technical solutions in this area. The issues of developing first generation biosensors are considered. However, the main disadvantage of such systems was the significant influence of ascorbic and uric acids on the generated signal, which significantly reduced their selectivity and accuracy. To solve this problem, it is possible to use ion-selective membranes such as Nafion and polycarbonate. The second generation of glucose biosensors uses artificial mediators to facilitate electron transfer between the enzyme and the electrode. These mediators can be immobilized directly by the enzyme or introduced into an enzyme-modified electrode. Suitable mediators include conducting organic salts, ferrocene, quinone compounds, ferricyanide, transition metal complexes, phenothiazine and foxazine compounds. Effective interactions between enzymes and mediators are critical for efficient electron transport. Various approaches have been proposed to tailor mediators, such as the use of Os complexes, noncovalent functionalization of carbon nanotubes, and stabilization of artificial mediators. The third generation of enzyme glucose biosensors uses direct electron transfer to perform electrochemical reduction. Various approaches have been considered, including reassembling apoproteins on cofactor-modified enzymes and electrically coupling enzymes to electrode surfaces using redox polymers or nanomaterials such as gold nanoparticles. Such approaches ensure the formation of an effective enzyme-electrode bond. In addition, the thickness of the enzymatic layer can affect the performance of the biosensor. External factors such as temperature, pH and humidity can have a significant impact on the performance of such electrodes.