Optimization of Electrochemical Aptasensor to Detect Glycated Hemoglobin (HbA1c) as a Diabetes Mellitus Biomarker

Glycated hemoglobin (HbA1c), a form of hemoglobin (Hb) bound to glucose, is a widely used biomarker for hyperglycemia, providing diagnostic and monitoring value in diabetes and prediabetes. This study investigated the development of an electrochemical aptasensor for HbA1c detection based on a screen‐printed carbon electrode (SPCE) modified with gold nanoparticles (AuNPs). A biotinylated aptamer was immobilized onto the electrode surface through streptavidin–biotin interaction, and the signal response was evaluated using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) in the presence of potassium ferricyanide ([K 3 Fe(CN) 6 ]) as a redox probe. The aptasensor response was characterized by a decrease in current upon HbA1c binding. Experimental parameters were systematically examined, and the optimal conditions were obtained at an aptamer concentration of 1.5 µg/mL, an aptamer incubation time of 60 min, and an HbA1c incubation time of 4 min. Under these conditions, the detection limit was 1.17% and the quantification limit was 3.5%, with a dynamic range of 2%–15%. The results indicate that this approach enables sensitive and selective HbA1c detection, supporting its potential application in diabetes diagnosis and monitoring through point‐of‐care (PoC) testing.