Carbon nanohorn modified platinum electrodes for improved immobilisation of enzyme in the design of glutamate biosensors

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Title: Carbon nanohorn modified platinum electrodes for improved immobilisation of enzyme in the design of glutamate biosensors
Authors: Ford, RochelleDevereux, Stephen J.Quinn, Susan J.O'Neill, Robert D.
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Date: 25-Jul-2019
Online since: 2020-09-29T09:32:04Z
Abstract: Electrochemical enzymatic biosensors are the subject of research due to their potential for in vivo monitoring of glutamate, which is a key neurotransmitter whose concentration is related to healthy brain function. This study reports the use of biocompatible oxidised carbon nanohorns (o-CNH) with a high surface area, to enhance the immobilization of glutamate oxidase (GluOx) for improved biosensor performance. Two families of biosensors were designed to interact with the anionic GluOx. Family-1 consists of covalently functionalised o-CNH possessing hydrazide (HYZ) and amine (PEG-NH2) terminated surfaces and Family-2 comprised non-covalently functionalised o-CNH with different loadings of polyethyleneimine (PEI) to form a cationic hybrid. Amperometric detection of H2O2 formed by enzymatic oxidation of glutamate revealed a good performance from all designs with the most improved performance by the PEI hybrid systems. The best response was from a o-CNH:PEI ratio of 1:10 mg mL-1, which yielded a glutamate calibration plateau, JMAX, of 55 ± 9 μA cm-2 and sensitivity of 111 ± 34 μA mM-1 cm-2. The low KM of 0.31 ± 0.05 mM indicated the retention of the enzyme function, and a limit of detection of 0.02 ± 0.004 μM and a response time of 0.88 ± 0.13 s was determined. The results demonstrate the high sensitivity of these biosensors and their potential for future use for the detection of glutamate in vivo.
Funding Details: Irish Research Council
University College Dublin
Type of material: Journal Article
Publisher: The Royal Society of Chemistry
Journal: Analyst
Volume: 144
Issue: 17
Start page: 5299
End page: 5307
Copyright (published version): 2019 The Royal Society of Chemistry
Keywords: Amino acid oxidoreductasesBiosensing techniquesCarbonElectrochemical techniquesElectrodesImmobilized enzymesGlutamic acidHydrogen peroxideLimit of detectionNanostructuresOxidation-reductionPlatinumPolyethyleneimine
DOI: 10.1039/c9an01085h
Language: en
Status of Item: Peer reviewed
ISSN: 0003-2654
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Appears in Collections:Chemistry Research Collection

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