Escherichia coli and its application in a mediated amperometric glucose sensor

Area of Science:

• Biomedical Engineering
• Electrochemistry
• Biosensors

Background:

• Glucose dehydrogenase is a key enzyme for glucose metabolism.
• Mediated amperometric sensors offer sensitive glucose detection.
• Cofactor dependency can be exploited for selective biosensing.

Purpose of the Study:

• To develop a novel amperometric glucose sensor using Escherichia coli.
• To investigate the role of pyrroloquinoline quinone (PQQ) as a cofactor.
• To assess the sensor's performance, including interference, stability, and reusability.

Main Methods:

• Immobilizing E. coli cells containing apo-glucose dehydrogenase on a carbon paste electrode.
• Utilizing 2,3-dimethoxy-5-methyl-1,4-benzoquinone (Q(0)) as an electron transfer mediator.
• Measuring current generated from electrocatalytic oxidation of glucose in the presence of PQQ.

Main Results:

• The sensor required PQQ for glucose oxidation current generation.
• The sensor showed high insensitivity to dioxygen across various conditions.
• A rapid response time (2 min) and good reusability (with EDTA treatment) were observed.
• Lyophilized E. coli cells maintained catalytic activity for over six months.

Conclusions:

• A novel, PQQ-dependent amperometric glucose sensor was successfully constructed using E. coli.
• The sensor offers selective and stable glucose detection, free from redox active substance interference.
• The developed biosensor demonstrates robustness, reusability, and long-term storage stability.