Development of electrochemical panel systems and biosensor applications

Early diagnosis of cancer is of critical importance for treatment success and patient prognosis. While diagnostic methods based on single biomarkers may be insufficient, the simultaneous evaluation of multiple biomarkers increases diagnostic accuracy. Especially in ovarian cancer, the levels of AGR2, FOLR1, GLY, and SMRP increase; therefore, the rapid and sensitive detection of these biomarkers is crucial for early diagnosis and monitoring. In this study, single and panel immunosensors for the detection of AGR2, FOLR1, GLY, and SMRP were developed using low-cost and disposable single and quadruple handmade electrodes. The produced electrodes were modified with AuNP, and the AuNP modification conditions were optimized. Morphological, chemical, and electrochemical characterizations of the modified electrodes were performed. Using single and quadruple electrodes, single and panel immunosensors for AGR2, FOLR1, GLY, and SMRP were prepared. The optimum antibody concentration and antibody/antigen incubation times were determined for the single immunosensors, and the panel immunosensors were prepared under these optimized conditions. The analytical performance parameters (linear range, detection limit, repeatability, stability, selectivity, and regeneration) of the single and panel immunosensors were evaluated, revealing that the sensors provided a low detection limit, a wide linear range, and high selectivity. Furthermore, although they are disposable, it was found that they could be regenerated twice. The separate and simultaneous determination of biomarkers at pg mL⁻¹ levels in commercial human serum samples was successfully performed, and high recovery values were obtained. It was determined that the single and panel AGR2, FOLR1, GLY, and SMRP immunosensors could be stored for up to 12 weeks. Method validation of the developed single and quadruple immunosensors was performed with antigen analyses using ELISA kits, and statistical analyses showed that the results were similar. The prepared disposable panel biosensors stand out as a fast, practical, and reliable candidate for use in point-of-care testing.