Glutamate oxidase biosensor based on mixed ceria and titania nanoparticles for the detection of glutamate in hypoxic environments

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• 作者：R谋fat Emrah 脰zel ; Cristina Ispas ; Mallikarjunarao Ganesana ; J.C. Leiter ; Silvana Andreescu
• 关键词：Microbiosensor ; Nanoparticles ; Oxygen ; Ceria ; Hypoxia ; Neurotransmitters ; Glutamate
• 刊名：Biosensors and Bioelectronics
• 出版年：15 February, 2014
• 年：2014
• 卷：52
• 期：Complete
• 页码：397-402
• 全文大小：1409 K

文摘

We report on the design and development of a glutamate oxidase (GmOx) microelectrode for measuring l-glutamic acid (GluA) in oxygen-depleted conditions, which is based on the oxygen storage and release capacity of cerium oxides. To fabricate the biosensor, a nanocomposite of oxygen-rich ceria and titania nanoparticles dispersed within a semi-permeable chitosan membrane was co-immobilized with the enzyme GmOx on the surface of a Pt microelectrode. The oxygen delivery capacity of the ceria nanoparticles embedded in a biocompatible chitosan matrix facilitated enzyme stabilization and operation in oxygen free conditions. GluA was measured by amperometry at a working potential of 0.6 V vs Ag/AgCl. Detection limits of 0.594 碌M and 0.493 碌M and a sensitivity of 793 pA/碌M (RSD 3.49%, n=5) and 395 pA/碌M (RSD 2.48%, n=5) were recorded in oxygenated and deoxygenated conditions, with response times of 2 s and 5 s, respectively. The biosensor had good operational stability and selectivity against common interfering substances. Operation of the biosensor was tested in cerebrospinal fluid. Preliminary in vivo recording in Sprague-Dawley rats to monitor GluA in the cortex during cerebral ischemia and reperfusion demonstrate a potential application of the biosensor in hypoxic conditions. This method provides a solution to ensure functionality of oxidoreductase enzymes in oxygen-free environments.