| Abstract [eng] |
Diabetes mellitus is a disease characterized by high blood glucose levels due to insufficient insulin production or cellular resistance to insulin. According to the World Health Organization (WHO), the number of people with diabetes is increasing. In 1990, it was estimated that 200 million people had this disease, and in 2022, this number had increased to 830 million. Currently, there are a number of approved glucose sensors on the market, but their high demand and importance for human health mean that their characteristics need to be continuously improved. The aim of this work was to develop an electrochemical glucose biosensor modified with polyaniline nanostructures or their nanocomposite. The study found that polyaniline nanostructures synthesized by interfacial polymerization (PANII) were irregular and of different shapes, with a length range from 1.57 µm to 2.98 µm. PANI nanostructures synthesized by chemical polymerization with cetyltrimethylammonium bromide (PANIII) were in the form of nanoclips with a thickness of 1.2 ± 0.18 µm. By optimizing the electrode surface modification conditions, it was found that drop-casting solutions of PANI nanostructures and glucose oxidase onto the electrode surface one after the other gives better results than modifying the electrode with a mixture of PANI nanostructures and GOx. It was found that when modifying the electrode surface with PANII or PANIII nanostructures, their optimal concentration is 0.5 mg·ml-1. When modifying the electrode surface with a PANII/MXene nanocomposite, the best results were achieved using a mixture of 0.5 mg·ml-1 PANII with 0.025 mg·ml-1 MXenes. Comparing the results of electrodes modified with different PANI nanostructures or their nanocomposite with MXenes, it was found that the best results were obtained when the glassy carbon electrode was modified with 0.5 mg·ml-1 PANII nanostructures and 20 mg·ml-1 glucose oxidase. The analytical characteristics of the developed electrochemical glucose sensor were calculated: LOD – 0.0107 mmol·l-1, LOQ – 0.0356 mmol·l-1, sensitivity – 85.82 µA (mmol·l-1)-1·cm-2. Linear range was observed in the glucose concentration range of 0.1 – 5 mmol·l-1. A study of the interferences of electroactive materials on the signal of an electrochemical glucose biosensor showed that ascorbic and uric acids have a minor influence on the recorded signals, but the developed biosensor is suitable for use. |
