A disposable electrochemical sensor designed to estimate glycated hemoglobin (HbA1c) level in whole blood

Abstract

The level of glycated hemoglobin percentage (HbA1c %), referring to the concentration ratio of HbA1c to total hemoglobin (Hb), has been used to accurately determine stage-wise diabetes for a long time period. Measurement of HbA1c alone may result in an error for monitoring glycemia in patients with diabetes. Addressing this challenge, we report an electrochemical method that senses both Hb and HbA1c using two chemically modified electrodes (SPCE/CNT-Nf@Hb-Nf and SPCE*/AQBA-HbA1c). For the determination of Hb, MultiWalled Carbon Nanotubes (MWCNT) with Nafion (Nf) were fabricated on a Screen Printed Carbon Electrode (SPCE), and the resulting modified electrode (SPCE/CNT-Nf@Hb-Nf) provided a redox signal for whole blood/Hb standard samples for electroactive Fe2+/Fe3+ that exist in heme proteins. A voltammetric sensor for HbA1c was developed using anthraquinone boronic acid (AQBA) by modifying a pre-anodized, screen-printed carbon electrode (SPCE*). The resulting SPCE*/AQBA electrode was able to complex with applied HbA1c through specific boronic acid–diol recognition. The binding of AQBA to HbA1c decreased its redox peak current, which led to the determination of HbA1c. Under optimized conditions, the sensor displays a linear response of 9.4–16.4 g/dL Hb and 31.2−500 nM HbA1c concentration range, with detection limit (S/N = 3) of 4.2 nM for HbA1c. In addition, the percentage concentration of HbA1c was successfully determined in whole blood samples collected clinically. The results were also compared with those obtained using the High-Performance Liquid Chromatographic (HPLC) method for validation and the correlation value of 0.95 indicates that this sensor holds promise as a potential alternative method to analyze HbA1c clinically.