Fabrication of a Highly Sensitive Glucose-6-phosphate Biosensor Based on Direct Electron Transfer Using Phage Display and Autodisplay Technologies

Glucose in biological cells is metabolized and exists as glucose-6-phosphate (G6P). A G6P biosensor was fabricated using a combination of phage display and autodisplay technologies for the detection of G6P. Active G6P dehydrogenase (G6PDH) was expressed and anchored to the outer membrane of Escherichia coli (E. coli) cells using autodisplay technology. Autodisplayed G6PDH exhibited high activity as confirmed by OM protein analysis. A conductive nanomesh layer was formed using a phage display to enhance the direct electron transfer of the enzyme. G6PDH autodisplaying E. coli cells were then immobilized on the layer using a polyelectrolyte interlayer. The nicotinamide adenine dinucleotide phosphate redox pairs in the fabricated electrode of the autodisplayed G6PDH exhibited a redox reaction, resulting in a significant increase in the peak currents in the presence of G6P. The G6P biosensor exhibited a wide dynamic range with high sensitivity, exhibiting linear responses in the ranges of 0.1 fM – 10 nM and 10 nM – 100 μM. The biosensor detected G6P without interference from other sugar molecules. The combination of phage display and autodisplay technologies is a promising approach for the fabrication of highly sensitive and specific biosensors.