Electrochemical behavior and L-tyrosine sensing properties of nanostructured Cr, Sn and La-doped α-Fe2O3 interfaces

L-tyrosine (Tyr) is a promising biomarker for the diagnosis and monitoring of metabolic disorders and neurodegenerative diseases. This study reports on the electrochemical properties of α-Fe2O3 nanostructures doped with Cr, Sn and La, referred to as CrFeOx, SnFeOx and LaFeOx, respectively, and their application in the enzyme-free electrochemical Tyr sensors. These disposable sensors offer accurate Tyr concentration analysis at room temperature, addressing the limitations of current point-of-care diagnostic methods. The CrFeOx, SnFeOx, and LaFeOx nanostructures serve as selective agents for binding and recognizing Tyr, deposited onto disposable graphite pencil electrodes to form the electrochemical interface. The interfacial resistance, charge-transfer kinetics, mechanism, and reversibility are studied via extensive electrochemical measurements employing electro¬chemical impedance spectroscopy and cyclic voltammetry. Furthermore, differen¬tial pulse voltammetry demonstrates excellent Tyr sensing performance in the concen¬tration range of 0 to 80 μM with 2.65 µA µM-1 cm-2 sensitivity and 360 nM thres¬hold detection limit for the best-performing CrFeOx sensors. Hence, these α-Fe2O3-based sensor systems are practical and efficient for selective Tyr detection, offering potential advancements in personalized healthcare and early disease diagnosis.