An enhanced glucose biosensor using charge transfer techniques

An enhanced glucose biosensor based on a charge transfer technique glucose sensor (CTTGS) is described and demonstrated experimentally. In the proposed CTTGS, which is accumulation method (d-gluconate + H+) ion perception system, the quality of output signal with “signal integration cycles” is high. With the proposed CTTGS it is possible to amplify the sensing signals without an external amplifier by using an accumulation cycle. It can be supposed that measurements of small (d-gluconate + H+) ion fluctuation are difficult by ion-sensitive field effect transistor (ISFET) because the theoretical maximum sensitivity is only 59 mV/pH and the small output signals are buried in the 1/f noise component of the metal–insulator–semi-conductor field-effect transistor (MISFET). Therefore, the CTTGS has many advantages, such as high sensitivity, high accuracy, high signal-to-noise ratio (SNR), and has been successfully demonstrated using a charge transfer technique. The CTTGS exhibited excellent performance for glucose with a large span (1445 mV) and good reproducibility. Moreover, the CTTGS has good sensitivity in this range of 7.22 mV/mM, a lower detection limit of about 0.01 mM/L and an upper detection limit of about 200 mM/L compared with amperometric glucose analysis which has been studied recently. Under optimum conditions, the proposed CTTGS exceeds the performance of the widely used ISFET glucose sensor. The sensitivity of the CTTGS (7.22 mV/mM) was seven times higher than that of the ISFET (1 mV/mM). Furthermore, the sensitivity obtained for human glucose levels was 29.06 mV/mM with a non-linear error of ±0.27%; the linearity is y = 0.0294x + 1.8612 and R2 = 0.9999, which is acceptable for clinical application. Real sample analysis is investigated in blood glucose level by our developed CTTGS ISFET system.