Biosensor nanoarchitectonics of Cu–Fe-nanoparticles/Zeolite-A/Graphene nanocomposite for enhanced electrooxidation and dopamine detection

Cu–Fe NPs/ZEA/Gr electrochemical biosensor is developed by sol-gel spin coating technique, where copper-iron nanoparticles (Cu–Fe NPs) is synthesized using a chemical reduction method and modified with Zeolite & Graphene to develop a hybrid nanocomposite - Cu–Fe NPs/ZEA/Gr. The synthesized nanocomposite is then mixed with poly (vinyl alcohol) as a binding agent and coated on to the glass substrate to produce thin film electrode. Then the electrode was analyzed for structural and morphological studies using XRD, SEM, TEM, UV-VIS, absorption, and emission spectra. The presence of Cu–Fe NPs, ZEA, and Gr in the nanocomposite is confirmed by the XRD diffraction peaks, while SEM investigation revealed that the hybrid composite has a particle size of around 7.25 nm with a body-centred cubic structure. The TEM images show that bimetallic nanoparticles were incorporated into the ZEA shell, which was surrounded by a layer of transparent graphene. Furthermore, the nanocomposite exhibited a distinct absorption peak at 395 nm, as evidenced by UV-VIS, absorption, and emission spectra. The electrochemical tests demonstrated that the Cu–Fe NPs/ZEA/Gr nanocomposite electrode showed an excellent electrocatalytic and selective properties towards the electrooxidation of dopamine to dopamine-o-quinone. The detection limit of the Cu–Fe NPs/ZEA/Gr nanocomposite thin film was found to be 0.058 μM, with a sensitivity of 1.97 μAμM−1cm−2. The enhanced catalytic performance of the Cu–Fe NPs/ZEA/Gr electrode is attributed to the unique nanostructured materials coating on the glass substrate. The findings suggest that nano-hybrid materials can be a viable option for developing electrochemical biosensors to monitor dopamine levels in biological fluids. This indicates that the concept of nanoarchitectonics utilized to produce dopamine sensors may lead to new diagnostic and therapeutic approaches for neurological disorders associated with dopamine dysregulation.