Enzymatic glucose detection using ZnO nanorods on the gate region of AlGaN/GaN high electron mobility transistors

ZnO nanorod-gated AlGaN/GaN high electron mobility transistors (HEMTs) are demonstrated for the detection of glucose. A ZnO nanorod array was selectively grown on the gate area using low temperature hydrothermal decomposition to immobilize glucose oxidase (GO(x)). The one-dimensional ZnO nanorods provide a large effective surface area with high surface-to-volume ratio and provide a favorable environment for the immobilization of GO(x). The AlGaN/GaN HEMT drain-source current showed a rapid response of less than 5 s when target glucose in a buffer with a pH value of 7.4 was added to the GO(x) immobilized on the ZnO nanorod surface. We could detect a wide range of concentrations from 0.5 nM to 125 mu M. The sensor exhibited a linear range from 0.5 nM to 14.5 mu M and an experiment limit of detection of 0.5 nM. This demonstrates the possibility of using AlGaN/GaN HEMTs for noninvasive exhaled breath condensate based glucose detection of diabetic application. (c) 2007 American Institute of Physics.