scholarly journals Engineered Glucose Oxidase Capable of Quasi-Direct Electron Transfer after a Quick-and-Easy Modification with a Mediator

2020 ◽  
Vol 21 (3) ◽  
pp. 1137 ◽  
Author(s):  
Nanami Suzuki ◽  
Jinhee Lee ◽  
Noya Loew ◽  
Yuka Takahashi-Inose ◽  
Junko Okuda-Shimazaki ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Glucose Oxidase ◽  
Glucose Sensor ◽  
Direct Electron Transfer ◽  
Glucose Monitoring ◽  
Single Step ◽  
Redox Mediator ◽  
Electrochemically Active ◽  
Phenazine Ethosulfate ◽  
The Impact

Glucose oxidase (GOx) has been widely utilized for monitoring glycemic levels due to its availability, high activity, and specificity toward glucose. Among the three generations of electrochemical glucose sensor principles, direct electron transfer (DET)-based third-generation sensors are considered the ideal principle since the measurements can be carried out in the absence of a free redox mediator in the solution without the impact of oxygen and at a low enough potential for amperometric measurement to avoid the effect of electrochemically active interferences. However, natural GOx is not capable of DET. Therefore, a simple and rapid strategy to create DET-capable GOx is desired. In this study, we designed engineered GOx, which was made readily available for single-step modification with a redox mediator (phenazine ethosulfate, PES) on its surface via a lysine residue rationally introduced into the enzyme. Thus, PES-modified engineered GOx showed a quasi-DET response upon the addition of glucose. This strategy and the obtained results will contribute to the further development of quasi-DET GOx-based glucose monitoring dedicated to precise and accurate glycemic control for diabetic patient care.

In Vitro Evaluation of Miniaturized Amperometric Enzyme Sensor Based on the Direct Electron Transfer Principle for Continuous Glucose Monitoring

2022 ◽  
pp. 193229682110706
Author(s):  
Yutaro Inoue ◽  
Yasuhide Kusaka ◽  
Kotaro Shinozaki ◽  
Inyoung Lee ◽  
Koji Sode
Keyword(s):  
Electron Transfer ◽  
Continuous Glucose Monitoring ◽  
Glucose Sensor ◽  
Direct Electron Transfer ◽  
Glucose Dehydrogenase ◽  
Glucose Monitoring ◽  
Reference Electrode ◽  
Enzyme Sensor

Background: The bacterial derived flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase (FADGDH) is the most promising enzyme for the third-generation principle-based enzyme sensor for continuous glucose monitoring (CGM). Due to the ability of the enzyme to transfer electrons directly to the electrode, recognized as direct electron transfer (DET)-type FADGDH, although no investigation has been reported about DET-type FADGDH employed on a miniaturized integrated electrode. Methods: The miniaturized integrated electrode was formed by sputtering gold (Au) onto a flexible film with 0.1 mm in thickness and divided into 3 parts. After an insulation layer was laminated, 3 openings for a working electrode, a counter electrode and a reference electrode were formed by dry etching. A reagent mix containing 1.2 × 10−4 Unit of DET-type FADGDH and carbon particles was deposited. The long-term stability of sensor was evaluated by continuous operation, and its performance was also evaluated in the presence of acetaminophen and the change in oxygen partial pressure (pO2) level. Results: The amperometric response of the sensor showed a linear response to glucose concentration up to 500 mg/dL without significant change of the response over an 11-day continuous measurement. Moreover, the effect of acetaminophen and pO2 on the response were negligible. Conclusions: These results indicate the superb potential of the DET-type FADGDH-based sensor with the combination of a miniaturized integrated electrode. Thus, the described miniaturized DET-type glucose sensor for CGM will be a promising tool for effective glycemic control. This will be further investigated using an in vivo study.

Synthesis of gold nanoparticles supported on functionalized nanosilica using deep eutectic solvent for an electrochemical enzymatic glucose biosensor

2017 ◽  
Vol 5 (34) ◽  
pp. 7072-7081 ◽  
Author(s):  
Siva Kumar-Krishnan ◽  
M. Guadalupe-Ferreira García ◽  
E. Prokhorov ◽  
M. Estevez-González ◽  
Ramiro Pérez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Electron Transfer ◽  
Glucose Oxidase ◽  
Direct Electron Transfer ◽  
Deep Eutectic Solvent ◽  
Glucose Biosensor ◽  
Enzymatic Biosensor

Synthesis of AuNPs supported on nanosilica, mediated by deep eutectic solvent (DES), for efficient immobilization of glucose oxidase (GOx) and enhanced direct electron transfer in an enzymatic biosensor.

scholarly journals Enzyme-Based Biosensors: Tackling Electron Transfer Issues

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3517 ◽  
Author(s):  
Paolo Bollella ◽  
Evgeny Katz
Keyword(s):  
Mathematical Model ◽  
Electron Transfer ◽  
Fuel Cells ◽  
Glucose Oxidase ◽  
Rate Constant ◽  
Direct Electron Transfer ◽  
Redox Enzymes ◽  
Practical Applications ◽  
The Mathematical Model

This review summarizes the fundamentals of the phenomenon of electron transfer (ET) reactions occurring in redox enzymes that were widely employed for the development of electroanalytical devices, like biosensors, and enzymatic fuel cells (EFCs). A brief introduction on the ET observed in proteins/enzymes and its paradigms (e.g., classification of ET mechanisms, maximal distance at which is observed direct electron transfer, etc.) are given. Moreover, the theoretical aspects related to direct electron transfer (DET) are resumed as a guideline for newcomers to the field. Snapshots on the ET theory formulated by Rudolph A. Marcus and on the mathematical model used to calculate the ET rate constant formulated by Laviron are provided. Particular attention is devoted to the case of glucose oxidase (GOx) that has been erroneously classified as an enzyme able to transfer electrons directly. Thereafter, all tools available to investigate ET issues are reported addressing the discussions toward the development of new methodology to tackle ET issues. In conclusion, the trends toward upcoming practical applications are suggested as well as some directions in fundamental studies of bioelectrochemistry.

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