Sensitive Electrochemical Detection of Glucose at Glucose Oxidase-Cobalt Phthalocyanine-Modified Boron-Doped Diamond Electrode

Abstract

Electrochemical detection of glucose was achieved at a glucose oxidase (GOx)-cobalt phthalocyanine (CoPc)-modified borondoped diamond (BDD) electrode without any additional electron mediator in the electrolyte solution. The surface of the hydrogen-terminated BDD thin film prepared by microwave plasma-assisted CVD was modified with 4-vinylpyridine (4VP) via photochemical modification. The 4VP-BDD was then immersed in a CoPc solution to obtain CoPc-BDD. A poly(pphenylenediamine) (PPD) thin film containing GOx was coated on the CoPc-BDD electrode surface via electropolymerization. At the GOx/PPD-CoPc-BDD electrode, anodic current for glucose oxidation was observed with a sigmoidal voltammetric curve, indicating successful electron mediation of H 2 O 2 generated as the result of glucose oxidation at GOx. The signal-to-background ratio for voltammetric current of glucose detection was larger at the GOx/PPD-CoPc-BDD electrode than at the GOx/PPDmodified platinum electrode due to the smaller background current of the modified BDD electrode.

Cobalt Phthalocyanine Modified Electrodes Utilised in Electroanalysis: Nano-Structured Modified Electrodes vs. Bulk Modified Screen-Printed Electrodes

“…For example, the sensing of hydrogen peroxide has been extensively studied using metal phthalocyanines [ 6 – 8 ], and elegant work by Ozoemena et al [ 9 ] has shown that a cobalt phthalocyanine (CoPC)-cobalt (II) tetraphenylporphyrin (CoTPP)-glucose oxidase-Nafion ® layer modified glassy carbon can be usefully utilised for the sensing of glucose. Additionally similar work by Kondo et al [ 10 ] have reported a similar method utilising a boron-doped diamond electrode as the underlying electrode. Note that in both cases, electrocatalysis ( via the modified CoPC electrodes) towards the sensing of hydrogen peroxide produced from the enzymatic reaction is reported compared to the bare underlying/supporting electrode substrate [ 9 , 10 ].…”

“…Additionally similar work by Kondo et al [ 10 ] have reported a similar method utilising a boron-doped diamond electrode as the underlying electrode. Note that in both cases, electrocatalysis ( via the modified CoPC electrodes) towards the sensing of hydrogen peroxide produced from the enzymatic reaction is reported compared to the bare underlying/supporting electrode substrate [ 9 , 10 ]. Other studies by Wring et al [ 11 ] have reported CoPC to be electrocatalytic towards the analytes coenzyme A and reduced glutathione.…”

Printable Heterostructured Bioelectronic Interfaces with Enhanced Electrode Reaction Kinetics by Intermicroparticle Network

“…In the presence of glucose anodic current began to flow at +0.20 V versus Ag/AgCl and almost constant at beyond +0.35 V (Figure 2A). This current response observed resulted from the electrochemical oxidation of H 2 O 2 , 25 which was generated by the GOx in biological microparticles (BSA-GOxMPs) that were not observed in the control BSA-MPs (Figure 2A, insert). This illustrates the retention of the biocatalytic function of BSA-GOxMPs due to the relatively mild microparticle fabrication conditions at neutral pH, room temperature, and in an aqueous environment.…”

Polyoxometalate-Modified Boron-Doped Diamond Electrodes

“…The CoPc-modified BDD can also be applied to an electrochemical glucose sensor by covering a glucose oxidase/poly(p-phenylenediamine) layer on the surface. 18) Thus, surface modification to introduce appropriate surface functionalities is effective for the immobilization of functional molecules, such as biorelated molecules and catalysts. 19) Polyoxometalates (POMs) are discrete anionic metaloxygen clusters having a large variety of sizes, shapes, and nuclearities.…”