Chu Byung Hwan, Kang Byoung Sam, Hung Sheng Chun, Chen Ke Hung, Ren Fan, Sciullo Andrew, Gila Brent P, Pearton Stephen J
Department of Chemical Engineering, University of Florida, Gainesville, Florida, USA.
J Diabetes Sci Technol. 2010 Jan 1;4(1):171-9. doi: 10.1177/193229681000400122.
Immobilized aluminum gallium nitride (AlGaN)/GaN high electron mobility transistors (HEMTs) have shown great potential in the areas of pH, chloride ion, and glucose detection in exhaled breath condensate (EBC). HEMT sensors can be integrated into a wireless data transmission system that allows for remote monitoring. This technology offers the possibility of using AlGaN/GaN HEMTs for extended investigations of airway pathology of detecting glucose in EBC without the need for clinical visits.
HEMT structures, consisting of a 3-microm-thick undoped GaN buffer, 30-A-thick Al(0.3)Ga(0.7)N spacer, and 220-A-thick silicon-doped Al(0.3)Ga(0.7)N cap layer, were used for fabricating the HEMT sensors. The gate area of the pH, chloride ion, and glucose detection was immobilized with scandium oxide (Sc(2)O(3)), silver chloride (AgCl) thin film, and zinc oxide (ZnO) nanorods, respectively.
The Sc(2)O(3)-gated sensor could detect the pH of solutions ranging from 3 to 10 with a resolution of approximately 0.1 pH. A chloride ion detection limit of 10(-8) M was achieved with a HEMT sensor immobilized with the AgCl thin film. The drain-source current of the ZnO nanorod-gated AlGaN/GaN HEMT sensor immobilized with glucose oxidase showed a rapid response of less than 5 seconds when the sensor was exposed to the target glucose in a buffer with a pH value of 7.4. The sensor could detect a wide range of concentrations from 0.5 nM to 125 microM.
There is great promise for using HEMT-based sensors to enhance the detection sensitivity for glucose detection in EBC. Depending on the immobilized material, HEMT-based sensors can be used for sensing different materials. These electronic detection approaches with rapid response and good repeatability show potential for the investigation of airway pathology. The devices can also be integrated into a wireless data transmission system for remote monitoring applications. This sensor technology could use the exhaled breath condensate to measure the glucose concentration for diabetic applications.
固定化氮化铝镓（AlGaN）/氮化镓（GaN）高电子迁移率晶体管（HEMT）在呼出气冷凝液（EBC）的pH值、氯离子和葡萄糖检测领域展现出巨大潜力。HEMT传感器可集成到无线数据传输系统中，实现远程监测。这项技术为利用AlGaN/GaN HEMT对EBC中的葡萄糖进行检测以深入研究气道病理学提供了可能性，且无需患者前往临床就诊。
采用由3微米厚的未掺杂GaN缓冲层、30埃厚的Al(0.3)Ga(0.7)N间隔层和220埃厚的硅掺杂Al(0.3)Ga(0.7)N帽层组成的HEMT结构来制造HEMT传感器。用于pH值、氯离子和葡萄糖检测的栅极区域分别用氧化钪（Sc(2)O(3)）、氯化银（AgCl）薄膜和氧化锌（ZnO）纳米棒进行了固定化处理。
Sc(2)O(3)栅极传感器能够检测pH值范围为3至10的溶液，分辨率约为0.1 pH。用AgCl薄膜固定化的HEMT传感器实现了10^(-8) M的氯离子检测限。固定有葡萄糖氧化酶的ZnO纳米棒栅极AlGaN/GaN HEMT传感器在暴露于pH值为7.4的缓冲液中的目标葡萄糖时，漏源电流显示出小于5秒的快速响应。该传感器能够检测0.5 nM至125 microM的广泛浓度范围。
使用基于HEMT的传感器提高EBC中葡萄糖检测的灵敏度具有很大前景。根据固定化材料的不同，基于HEMT的传感器可用于传感不同物质。这些具有快速响应和良好重复性的电子检测方法在气道病理学研究中显示出潜力。这些设备还可集成到无线数据传输系统中用于远程监测应用。这种传感器技术可利用呼出气冷凝液来测量糖尿病应用中的葡萄糖浓度。
