Electrochemical aptasensor for ultrasensitive detection of glycated hemoglobin (HbA1c) using gold-modified SPCE

Accurate monitoring of diabetes mellitus (DM) biomarkers, particularly glycated hemoglobin (HbA1c), is essential for assessing long-term blood glucose control, optimizing therapeutic strategies, and preventing diabetes-related complications. To enhance the efficiency of this monitoring, electrochemical aptasensors based on screen-printed carbon electrodes (SPCE) modified with gold nanoparticles (AuNP) have been developed. The results demonstrate that the electrodeposition technique produces a uniform AuNP distribution and significantly increases the current responses of K₃[Fe(CN)₆] compared to bare SPCE. Aptamer immobilization using a streptavidin-biotin system via linker-mediated attachment exhibits high affinity for HbA1c, as evidenced by a significant decrease in current upon target binding.The analytical performance of the aptasensor shows a low detection limit of 8.34 pg/mL, with a linear detection range of 1 to 10 4 pg/mL. Moreover, the aptasensor exhibits good selectivity for HbA1c over hemoglobin, glucose, and palmitic acid, with a selectivity value of 82.56 %. Stability tests indicate that the sensor retains 90.38 % of its activity after 70 days of storage, confirming its reliability for HbA1c detection. This study contributes to the advancement of effective electrochemical biosensors for diabetes monitoring, enabling early diagnosis and improved disease management. • Gold nanoparticle electrodeposition on SPCE enhanced current response, achieving an HbA1c detection limit of 8.34 pg/mL. • Streptavidin-biotin immobilization ensured strong aptamer binding and high specificity for HbA1c over interfering molecules. • The aptasensor exhibited 82.56 % selectivity for HbA1c and maintained 90.38 % recovery after 70 days, ensuring reliability.