The pH Effect on the Response of Glutamate Oxidase Based Biosensor

Introduction: Glutamate is the major excitatory neurotransmitter in the central nervous system (CNS). It contributes in several physiological conditions such as brain development, memory and learning. However, increasing of the extracellular concentration of glutamate leads to excitotoxicity which is the central pathological pathway of neuronal injury. Therefore there is a need for rapid reproducible and sensitive methods to measure the concentration of glutamate in various biological samples such as extracellular fluids, brain and blood. In this study, a simple and efficient glutamate based electrochemical biosensor is fabricated for detection of glutamate in analytical and clinical samples. The fabricated biosensor is based on immobilization of the glutamate oxidase and nano chitosan at the surface of platinum electrode. It is worth to note that the optimum responses of the fabricated biosensor, depends on the pH. In this study, the effect of pH on the biosensor responses is investigated using cyclic voltametry method and the voltammograms was considered as the biosensor responses.Material and methods: Cyclic voltammetry method was utilized for evaluation of fabricated biosensor performance and voltammograms was considered as biosensor responses. All studies were carried out in buffer phosphate 0.1 M, 25ºC and scan rate 10 mv/s in presence of fixed concentration of glutamate (0.5 × 10-3 M). Buffer solutions at various pH values were tested to investigate the effect of pH. The pH effects on biosensor’s responses were evaluated in the range of 5.5 to 9.5.Results and conclusion: The results showed that the optimum responses of fabricated biosensor were occurred at pH 7.4. It is important to note that, this pH completely conform to the optimum pH of glutamate oxidase catalytic activity.

کلیدواژه ها:

Glutamate Biosensor ، Neurotransmitter ، Glutamate ، Glutamate Oxidase ، Cyclic Voltammetry