Development of Glutamate Sensor Based on Mxene/NiO Modified Screen Printed Carbon Electrode

Abstract

Glutamate plays a vital role as a neurotransmitter, contributing significantly to both physiological and pathological processes. Although enzymatic electrochemical sensors exhibit the ability to selectively detect glutamate, the presence of enzymes introduce sensor instability. Consequently, there is a pressing need for the advancement of enzyme-free glutamate sensors [1-3]. In this study, we have developed an incredibly sensitive non-enzymatic electrochemical sensor for detecting glutamate.This was achieved by synthesizing nanoparticles of nickel oxide (NiO) and physically combining them with MXene on a Screen-printed carbon electrode (SPCE)[2]. Fig. 1 shows the MXene-NiO nanoparticles (NPs) modification process on SPCE. In this work, cyclic voltammetry and amperometric techniques were carried out in a three-electrode system with an oxygen-saturated environment, where MXene-NiO/SPCE, pt wire, and Ag/AgCl electrode were used as working, counter, and reference electrode respectively. MXene-NiO/SPCE showed significant electro-catalytic activity in catalyzing the oxidation of glutamate in 0.1 M NaOH solution. A linear relationship was established between the current response and Glutamate concentration after the electrochemical experiments were conducted while working parameters were optimized. We conducted an extensive investigation of glutamate-sensing mechanism. The optimized sensor exhibited an irreversible oxidation process for glutamate, involving the transfer of one electron and one proton. It displayed a fast response time of < 5 s and a linear response within the concentration range of 20 to 300 µM at a pH of 7, with a LOD of 17.5 µM, sensitivity of 4500 µA.mM−1.cm−2. The morphology of the MXene-NiO composites was characterized using SEM, EDX, XRD, FT-IR, and UV spectroscopy techniques. The investigation into interference on the MXene-NiO/SPCE revealed a noteworthy current response to glutamate even in the presence of uric acid and ascorbic acid. As a result, the development of a reliable, enzyme-free glutamate sensor could be enabled by this simple sensor based on MXene-NiO composites.Fig. 1. The process of MXene/NiO/SPCE electrode.Reference[1] M. Jamal et al., Microsyst. Technol., 24, 4217–4223, 2018. doi: 10.1007/s00542-018-3724-6.[2] M. Jamal et al., Biosens. Bioelectron., 40, 213–218, 2013. doi: 10.1016/j.bios.2012.07.024.[3] K. M. Razeeb et al., Vertically Aligned Nanowire Array-Based Sensors and Their Catalytic Applications. In: Vestergaard, M., Kerman, K., Hsing, IM., Tamiya, E. (eds) Nanobiosensors and Nanobioanalyses, Springer, Tokyo, 2015. Figure 1