Yang Haipeng, Rahman Taibur, Du Dan, Panat Rahul, Lin Yuehe
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States; College of Materials Science and Engineering, Nanshan District Key Lab for Biopolymers and Safety Evaluation, and Shenzhen Key Laboratory of Special Functional Materials, Shenzhen University, Shenzhen 518060, P.R. China.
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States.
Sens Actuators B Chem. 2016 Jul;230:600-606. doi: 10.1016/j.snb.2016.02.113.
Printed Electronics has emerged as an important fabrication technique that overcomes several shortcomings of conventional lithography and provides custom rapid prototyping for various sensor applications. In this work, silver microelectrode arrays (MEA) with three different electrode spacing were fabricated using 3-D printing by the aerosol jet technology. The microelectrodes were printed at a length scale of about 15 μm, with the space between the electrodes accurately controlled to about 2 times (30 μm, MEA30), 6.6 times (100 μm, MEA100) and 12 times (180 μm, MEA180) the trace width, respectively. Hydrogen peroxide and glucose were chosen as model analytes to demonstrate the performance of the MEA for sensor applications. The electrodes are shown to reduce hydrogen peroxide with a reduction current proportional to the concentration of hydrogen peroxide for certain concentration ranges. Further, the sensitivity of the current for the three electrode configurations was shown to decrease with an increase in the microelectrode spacing (sensitivity of MEA30: MEA100: MEA180 was in the ratio of 3.7: 2.8: 1), demonstrating optimal MEA geometry for such applications. The noise of the different electrode configurations is also characterized and shows a dramatic reduction from MEA30 to MEA100 and MEA180 electrodes. Further, it is shown that the response current is proportional to MEA100 and MEA180 electrode areas, but not for the area of MEA30 electrode (the current density of MEA30 : MEA100 : MEA180 is 0.25 : 1 : 1), indicating that the MEA30 electrodes suffer from diffusion overlap from neighboring electrodes. The work thus establishes the lower limit of microelectrode spacing for our geometry. The lowest detection limit of the MEAs was calculated (with S/N = 3) to be 0.45 μM. Glucose oxidase was immobilized on MEA100 microelectrodes to demonstrate a glucose biosensor application. The sensitivity of glucose biosensor was 1.73 μAmM and the calculated value of detection limit (S/N = 3) was 1.7 μM. The electrochemical response characteristics of the MEAs were in agreement with the predictions of existing models. The current work opens up the possibility of additive manufacturing as a fabrication technique for low cost custom-shaped MEA structures that can be used as electrochemical platforms for a wide range of sensor applications.
印刷电子技术已成为一种重要的制造技术，它克服了传统光刻技术的几个缺点，并为各种传感器应用提供定制快速成型。在这项工作中，使用气溶胶喷射技术通过3D打印制造了具有三种不同电极间距的银微电极阵列（MEA）。微电极的打印长度尺度约为15μm，电极之间的间距被精确控制为迹线宽度的约2倍（30μm，MEA30）、6.6倍（100μm，MEA100）和12倍（180μm，MEA180）。选择过氧化氢和葡萄糖作为模型分析物来展示MEA在传感器应用中的性能。结果表明，在一定浓度范围内，电极可还原过氧化氢，还原电流与过氧化氢浓度成正比。此外，三种电极配置的电流灵敏度随微电极间距的增加而降低（MEA30：MEA100：MEA180的灵敏度之比为3.7：2.8：1），证明了这种应用的最佳MEA几何形状。还对不同电极配置的噪声进行了表征，结果表明从MEA30到MEA100和MEA180电极噪声大幅降低。此外，结果表明响应电流与MEA100和MEA180电极面积成正比，但与MEA30电极面积不成正比（MEA30：MEA100：MEA180的电流密度为0.25：1：1），这表明MEA30电极存在相邻电极的扩散重叠问题。这项工作因此确定了我们这种几何形状微电极间距的下限。计算得出MEA的最低检测限（信噪比S/N = 3）为0.45μM。将葡萄糖氧化酶固定在MEA100微电极上以展示葡萄糖生物传感器的应用。葡萄糖生物传感器的灵敏度为1.73μA/ mM，计算得出的检测限（S/N = 3）值为1.7μM。MEA的电化学响应特性与现有模型的预测一致。当前的工作开启了增材制造作为一种制造技术的可能性，可用于制造低成本的定制形状MEA结构，这些结构可用作广泛传感器应用的电化学平台。
