Abstract: Hemoglobin A1c (HbA1c), a key biomarker for long-term glucose regulation, is essential for diagnosing and managing diabetes mellitus. However, conventional HbA1c detection methods often suffer from limited sensitivity, narrow detection ranges, slow response times, and poor long-term stability. In this study, we developed a high-performance amperometric biosensor for the selective detection of Fructosyl Valine (FV), a model compound for HbA1c, by immobilizing Fructosyl Amino Acid Oxidase (FAAO) onto a glassy carbon electrode modified with electrospun polyaniline/polyindole-Mn₂O₃ nanofibers. Operating at an applied potential of 0.27 V versus Ag/AgCl, the biosensor achieved a rapid detection time of 2 s for FV concentrations up to 50 μM, with a signal-to-noise ratio of 3. Under optimized conditions (pH 7.0 and 35 °C), the biosensor exhibited a wide linear detection range from 0.1 to 3 mM and a high sensitivity of 38.42 μA/mM. Importantly, the sensor retained approximately 70% of its initial activity after 193 days of storage at 4 °C, demonstrating excellent long-term stability. These results suggest that the FAAO/polyaniline/polyindole-Mn₂O₃ nanocomposite-based biosensor offers a promising platform for sensitive, rapid, and durable detection of HbA1c, providing significant potential for improving diabetes monitoring and management.

Key words: Biosensor, Electrospun nanofibers, Enzymatic immobilization, HbA1c · Polyaniline, Polyindole, Diabetes monitoring')">Biosensor, Electrospun nanofibers, Enzymatic immobilization, HbA1c · Polyaniline, Polyindole, Diabetes monitoring