Low-Potential Operation of Direct Electron Transfer Biosensor Strip With Single-Walled Carbon Nanotubes and Flavin Adenine Dinucleotide Glucose Dehydrogenase

In this letter, the low-potential operation (+0.05 V versus Ag/AgCl) of a direct electron transfer (DET) glucose biosensor strip with a small-volume (2
μ
L) electrochemical capillary chamber is demonstrated. We constructed a DET formation in which debundled single-walled carbon nanotubes were placed near the reaction center pocket of flavin adenine dinucleotide glucose dehydrogenase. The DET biosensor has the advantage of long-term stability, unlike an electron transfer mediator, which is naturally reduced to cause sensing malfunction in a mediated electron transfer biosensor, adopted in commercial devices. However, DET biosensors still have a high working potential owing to their overpotential. In this letter, we have resolved this issue via a very short interval (1 ms) voltage application (+0.4 V) that reduced the onset potential, in other words, enhanced the current owing to an enzymatic reaction. The DET biosensors had a sensitivity of 0.055
μ
A (mg/dl)
⁻¹
mm
⁻²
, a linear dynamic range of 0–750 mg/dL, and a detection limit of 0.9 mg/dL.