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 mu M. 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.