Sillenite-type multiferroic Bi12.5Fe0.5O19.5 decorated ReSe2 as an electrochemical platform for sensitive and selective detection of stress hormones in human biological fluids.

Norepinephrine (NEP) or noradrenaline is a key catecholamine that functions both as a neurotransmitter and hormone, playing a pivotal role in mood regulation, cardiovascular function, and the stress response. Reliable and sensitive detection of NEP is crucial for clinical diagnosis and health monitoring. Herein, we describe a novel electrochemical sensor that enables efficient and affordable detection of NEP based on Sillenite-type multiferroic bismuth ferrite integrated onto rhenium diselenide nanosheets (Bi12.5Fe0.5O19.5@ReSe2) nanohybrid. The ReSe2 nanosheets were synthesized by the hot injection method, and the Bi12.5Fe0.5O19.5@ReSe2 nanohybrid was synthesized using a hydrothermal route and uniformly deposited on the GCE via drop-casting. Comprehensive structural and morphological characterizations were conducted using advanced spectroscopic techniques. The electrochemical characteristics of the sensor were inspected via voltammetry and impedance analysis. The synergistic interaction within the nanocomposite enhances electrochemical performance. The sensor exhibited a linear detection response to NEP in the 0.5-993 μM range, with a detection limit of 0.112 μM and a sensitivity of 0.154 μA μM-1 cm-2. It showed excellent precision, stability, and strong resistance to interference from common biomolecules. Its successful application to NEP detection in human fluids (serum and urine) with satisfactory recovery confirms its promise for use in clinical diagnostics and real-time physiological monitoring.