Electrochemical solid-state nanosensor based on a dual amplification strategy for sensitive detection of (FeIII-dopamine)

Abstract Over the past decades, according to empirical studies, it has been determined that dopamine metabolism plays a key role in many neuropsychiatric diseases. The development of dual-response electrochemical sensors is still in its infancy during the sensor-based detection methods for dopamine. Hence, a novel electrochemical sensor with dual amplification strategy was designed and constructed. In the molecular design of the solid-state structure, a flexible ITO/PET was used. Several nanometric layers of graphene oxide (GO) were deposited on the surface of the ITO/PET using the electrophoretic deposition (EPD) method. Then, during the layer-by-layer (LbL) assembly, the synthesized electro-active naphthalimide dye/LDH nanoplatelets matrix (NALD-n) was displayed in successive layers. The minimum sheet resistance, uniform morphology, and high electrocatalytic activity of the modified matrix film were obtained in the fifth cycle of the LbL assembled (NALD-5) modified electrode. This molecular design resulted in a significant increase in the fluorescence emission of electro-active dye in the sensor's bed containing LDH nanoplatelets and eliminating the effect of GO quenching. This solid sensor was used to detect dual Fe 3+ /dopamine through an electro-active naphthalimide probe on the surface. In this sensor, in terms of electrochemical/optical changes of solid-state, the (OFF/ON/OFF) system was created so that the fluorescence emission decreased with the presence of dopamine molecules. The cyclic voltammetric changes of the sensor were well tolerated at a linear range of [1.0 × 10 −10 -1.5 × 10 −8  M] for the selective sensing of dopamine with a detection limit (LOD) of 0.06 nM.