Fabrication of a mesoporous CoFe2O4/rGO nanohybrid and laccase interface biosensor for rapid detection of adrenaline for neurodegenerative disease diagnosis†

A hydrothermally synthesized mesoporous CoFe₂O₄ (CF)/reduced graphene oxide (rGO) nanohybrid (nh) provides the electroactive surfaces and facilitates fast electron transfer between the nanofabricated bioelectrode–electrolyte interfaces, responsible for the high electrocatalytic activity in sensing adrenaline (AD). A promising biosensor for detecting adrenaline and bovine serum albumin (BSA) used as a real sample for diagnosing neurodegenerative diseases is described here. This study focuses on the electrochemical impedance biosensing of AD because of its unique ability to identify various kinds of health issues, including blood pressure, fight-or-flight response, memory loss, multiple sclerosis, Parkinson's disease, and cardiac asthma. A La/CF/rGO/ITO bioelectrode (La: Laccase) is the biosensor component. It is created by electrophoretic deposition (EPD) of a CF/rGO nh and drop-casting immobilization of the La-enzyme. The low charge-transfer resistance (R_ct) of the CF/rGO electrode was sensed by electrochemical impedance spectroscopy (EIS), confirming the synergistic impact of CF/rGO on the La/CF/rGO/ITO fabricated bioelectrode in AD detection. This gives the high heterogeneous rate constant (K_s: 2.83 × 10⁻⁴) and increases the surface adsorption and diffusion coefficient (D: 5.25 × 10⁻² cm² s⁻¹). The proposed biosensor exhibited high sensitivity (0.214 Ω μM⁻¹ cm⁻²), long linear range (1 to 500 μM), lower detection limit (LoD: 40.3 μM), high selectivity (RSD 5.8%), and stability with good recovery %, emphasizing its potential implementation in biosensing techniques for monitoring neurotransmitter disorders in real world applications.