DEVELOPMENT OF NOVEL ELECTROCHEMICAL SENSORS BASED ON NANOMATERIALS AND POLYMERS FOR 8-HYDROXY-2'-DEOXYGUANOSINE, 1-HYDROXYPYRENE, 5-AMINOSALICYLIC ACID, AND SULFAPYRIDINE DETECTION

Abstract

This research concentrated on the development of an electrochemical sensor based on nanomaterials, poly(amino acids), or both for the detection of important biomarkers in clinical applications, which could be classified into three sub-projects. In the first sub-project, an electrochemical sensor based on a nanocomposite between poly(L-methionine) and gold nanoparticle-modified screen-printed graphene electrode was developed for the sensitive and selective detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the presence of uric acid at normal levels in urine. A sodium phosphate buffer solution containing sodium chloride and sodium dodecyl sulfate was used as the supporting electrolyte to increase selectivity for 8-OHdG detection. In the second sub-project, a novel detection for 1-hydroxypyrene (1-OHP) used only a single step of electropolymerization of poly(L-glutamic acid)-modified screen-printed graphene was developed. The electrochemical response of 1-OHP on the modified sensor was three times larger than that of the unmodified sensor. For practical applications, it was utilized to determine 1-OHP in six urine samples, without any interference. Lastly, in the third sub-project, the simultaneous detection of 5-aminosalicylic acid (5-ASA) and sulfapyridine (SPD) using poly(L-methionine)-modified screen-printed graphene electrodes were reported for the first time. The detection of 5-ASA and SPD indicated the therapeutic determinant of the action of sulfasalazine, which is widely used for the treatment of rheumatoid arthritis and inflammatory bowel disease. As aforementioned, these developed electrochemical sensors and proposed methodologies could be directly applied to determine specific target analytes in real human serum and urine samples without additional sample preparation. The results obtained provided satisfactory analytical performances with high accuracy, precision, reproducibility, stability, and reliability.-