Synthesis and Characterization of Cysteine Grafted cu MOF/ZnO/PANI nanocomposite and its potential application as non- enzymatic electrochemical sensing of dopmine

Abstract

Electrochemical detection, a rapidly developing discipline, has shown great promise in monitoring neurotransmitter levels, particularly dopamine, which is essential for diagnosing neurological illnesses like Parkinson's disease. These technologies have several benefits: they are easy, cost-effective, extremely sensitive, energy-efficient, and have immediate control systems. Despite the advantages, the manufacture of electrochemical biosensors remains challenging. For the development of cutting-edge electrochemical sensors, Metal-Organic Frameworks (MOFs) reinforced with nanostructured materials provide higher thermal and chemical stability. By acting as platforms for conducting nanoparticles, these MOF composites greatly improve electrocatalytic performance. Therefore, the electrochemical detection of environmental and biological targets has been revolutionized by incorporating such materials. The importance of MOFs and nanocomposites in biosensor applications for electrochemical sensing is highlighted in the current study. This present investigation discusses the synthesis, characterization, and potential use of a Cysteine grafted Cu MOF/ZnO/PANI nanocomposite for non-enzymatic electrochemical dopamine sensing. The goal was to create electrochemical biosensors for selective dopamine detection over a broad concentration range that have great sensitivity and low detection limits. To improve the performance of the electrode, nanocomposites Cysteine grafted Cu MOF/ZnO/PANI were deposited on their surface on a Glassy Carbon Electrode (GCE). Using X-ray diffraction, the structural characteristics of functionalized electrodes are evaluated. Scanning electron microscopy (SEM) was used to examine the morphology of electrode materials. At room temperature, a Gamry Potentiostat was employed for the electrochemical tests. The three-electrode arrangement consisted of the working electrodes, which were the materials deposited on modified GCE, the reference electrode made of Ag/AgCl, and the counter electrode made of platinum wire. The process was determined to be diffusion-controlled dopamine oxidation. Dopamine underwent spontaneous adsorption on the electrode surface through an electrochemically reversible mechanism. The concentration of dopamine in a 0.1 M PBS electrolytic solution was accurately measured using sensors made of Cysteine grafted Cu MOF/ZnO/PANI on a xix glassy carbon electrode (GCE). Despite the presence of various biological interfering factors, the non-enzymatic electrochemical sensors demonstrated a remarkable level of selectivity towards dopamine. Cysteine grafted Cu MOF/ZnO/PANI produced the lowest dopamine detection limit, at 0.39 μM and the sensitivity observed was 122.57 μAmM-1cm-2. The Cysteine grafted Cu MOF/ZnO/PANI on GCE sensors, however, were appropriate for dopamine concentration monitoring (i.e., 0.05-0.8 mM). In summary, the research conducted in this study on electrochemical biosensors demonstrated remarkable sensitivity and selectivity in detecting dopamine, even when there were other interfering substances present. The results showed that the enhanced catalytic and conductive properties of MOFs, when combined with nanostructured materials, are the primary factors that affect the performance of these electrochemical sensors. This study introduces innovative nanomaterial-based platforms that provide a viable foundation for creating advanced electrochemical sensors for medical diagnostic purposes.