A Signal Enhancement Microneedle Glucose Sensor With Extended Gate Thin-Film Transistors Structure

This article reports a glucose sensor based on extended-gate amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (EG-TFTs) combined with microneedles (MNs) for diabetes detection. The TFT connects the solid MNs through the extended gate to convert the MN electrical signal, improving signal stability and enhancing noise suppression, and meanwhile provides higher sensitivity. Two sets of MNs are used to realize a two-electrode system for responding to glucose currents. The MN sensors show good performance. By adjusting the aspect ratio of the TFT to accommodate the glucose redox reaction generated by the MN sensor, more sensitive detection can be achieved, with a sensitivity reaching 0.55 μA/mM and a linear relation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> = 0.9931. Its relative current change exhibits a significant superiority over that of the MN sensing electrode, and its sensitivity is more than twice as high as that of the MN sensor, thereby demonstrating outstanding performance. This novel EG-TFT MN sensor will promote the development of highly integrated wearable biosensors that can be extended to detect diverse biomarkers in interstitial fluids (ISFs).