Hybrid polypyrrole/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate flexible electrode for monoamine transmitter serotonin in human fluids

[Display omitted] •Hybrid conducting polymers PPY/PEDOT:PSS composite was employed for detecting ST.•The modified electrode exhibited detection of ST at a picomolar concentration (0.45 nM), high linear range (0.0083–153.63 µM) and good sensitivity (7.4248 µA/µM cm−2).•PPY/PEDOT:PSS/GCE demonstrated good repeatability, and good stability. Serotonin (ST) is a critical neurotransmitter involved in various physiological and psychological processes, making its precise detection essential for clinical and research applications. Electrochemical sensors have emerged as a promising approach for ST detection due to their sensitivity and simplicity. In this study, we developed a ST sensor using a composite of polypyrrole and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PPY/PEDOT:PSS), which leverages the synergistic properties of these conducting polymers (CPs). CPs like PPY and PEDOT are known for their excellent electrical conductivity, chemical stability, and ease of processing, making them ideal materials for electrochemical sensing. The sensor demonstrated excellent analytical performance, achieving a picomolar detection limit (45 pM), a wide linear range (0.0083–153.63 µM), and high sensitivity (7.4248 µA/µM cm-2). The developed sensor presents good repeatability and stability, ensuring reliable measurements and good specificity with the presence of other potential interferents like dopamine (DA) and ascorbic acid (AA), glucose (Glu), uric acid (UA), histamine (HTA), cystine (Cys), and tyrosine (Tyr). Additionally, the sensor showed high recovery rates when tested with human fluids, including urine, serum, tears, and saliva, indicating its potential for practical applications in clinical diagnostics. This study highlights the effectiveness of the PPY/PEDOT:PSS composite as a promising material for the sensitive and accurate detection of ST.