Engineered PQQ Glucose Dehydrogenase‐Based Enzyme Sensor for Continuous Glucose Monitoring

Abstract

Continuous glucose monitoring (CGM) is expected to become an ideal way to monitor the glycemic level of diabetic patients. A recent trend in the disposable self blood glucose sensing development has been the use of pyrroloquinoline quinone-harboring glucose dehydrogenase (PQQGDH). However, due to a number of limitations of PQQGDH, conventionally utilized glucose oxidase (GOD) remains widely utilized in CGM. Two major problems that arose in the application of PQQGDH for CGM are the poor stability and its requirement for artificial electron acceptors for electrochemical measurement. To solve these problems, we investigated the amenability of our engineered PQQGDH Ser415Cys, which has a far superior thermal stability over the wild-type enzyme, for the CGM system, and the applicability of cyt b 562 as the electron mediator to construct a CGM system free of synthetic mediator. As a result, the operational stability of CGM system employing Ser415Cys co-immobilized with cyt b 562 was far superior to that of the wild-type enzyme-based electrode, with more than 60% of the initial response observed after 72 hr at 378C. We achieved the successful application of PQQGDH in continuous operation without a significant decrease in the sensor signal.

A multilayered sulfonated polyaniline network with entrapped pyrroloquinoline quinone-dependent glucose dehydrogenase: tunable direct bioelectrocatalysis

“…This is not usual for PQQ-GDH, which oen shows a stronger decrease in activity due to disassembly of PQQ from the enzyme. [55][56][57] These results demonstrate that the entrapment of PQQ-GDH in the sulfonated polyaniline lms leads to an improved long-term stability, making this type of architecture promising to be considered as a candidate for the construction of glucose biosensors.…”

Electrochemical Sensors for Clinic Analysis

“…Because of the poor stability of enzyme and the requirement for artificial electron acceptors for electrochemical measurement, continuous glucose monitor based on PQQ-GDH was hardly applied, Okuda et al investigated engineered PQQ-GDH Ser415Cys, which had a far superior thermal stability over the wild-type enzyme and immobilized cyt b 562 as the electron mediator to get long-term signal [ 89 ].…”

Protein Engineering – An Option for Enzymatic Biofuel Cell Design

“…These enzymes should be immobilized in an oriented way on electrode surfaces without losing any activity in pretreatment or during immobilization. Current protein engineering technologies allow to develop "bioelectrozymes" for enzymatic biofuel cell applications and many reported success stories show that biocatalyst properties can be improved through directed evolution technologies [2,3,29].…”