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Antibody-functionalized, Au-gated AlGaN∕GaN high electron mobility transistors (HEMTs) were used to detect botulinum toxin. The antibody was anchored to the gate area through immobilized thioglycolic acid. The AlGaN∕GaN HEMT drain-source current showed a rapid response of less than 5s when the target toxin in a buffer was added to the antibody-immobilized surface. We could detect a range of concentrations from 1to10ng∕ml. These results clearly demonstrate the promise of field-deployable electronic biological sensors based on AlGaN∕GaN HEMTs for botulinum toxin detection.

The effect of Pt metal thickness on the hydrogen sensing sensitivity of Pt-coated, multi-layered graphene grown by chemical vapor deposition on Si-polar 4H-SiC, was investigated. As-grown graphene samples and graphene samples coated with 1 or 4 nm thick Pt films were used in this study. Compared to graphene without platinum, significantly improved hydrogen detection sensitivity was observed with the addition of platinum films. The highest hydrogen sensitivity was observed with the graphene sensor with 1 nm platinum coating. The platinum coated graphene sensor also showed good selectivity for hydrogen detection over methane, ammonia, oxygen, and nitrogen oxide. VC 2011 The Electrochemical Society. [DOI: 10.1149/1.3589250] All rights reserved. Manuscript submitted March 17, 2011; revised manuscript received April 6, 2011. Published May 5, 2011. Hydrogen gas is widely used in industrial applications including fossil fuel production, metal refining, and hydrochloric acid produc-tion. In recent years, next-generation applications such as hydrogen-based zero carbon emission vehicle technologies have emerged. Since hydrogen is subject to explosion risk at concentrations between 4 and 75 % by volume, safety is a key concern when work-ing with hydrogen-containing gases. Therefore, it is vital to monito

The detection of lactic acid with ZnO nanorod-gated AlGaN∕GaN high electron mobility transistors (HEMTs) was demonstrated. The array of ZnO nanorods provided a large effective surface area with a high surface-to-volume ratio and a favorable environment for the immobilization of lactate oxidase. The HEMT drain-source current showed a rapid response when various concentrations of lactic acid solutions were introduced to the gate area of the HEMT sensor. The HEMT could detect lactic acid concentrations from 167nM to 139μM. Our results show that portable, fast response, and wireless-based lactic acid detectors can be realized with AlGaN∕GaN HEMT based sensors.