Tian Yuan, Zhao Rui, Liu Yi, Yu Xiaomei
National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Institute of Microelectronics, Peking University, Beijing 100871, China.
Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 038507, China.
Micromachines (Basel). 2020 Nov 12;11(11):1001. doi: 10.3390/mi11111001.
This paper introduces a piezoresistive microcantilever with a low spring constant. The microcantilever was fabricated with titanium (Ti) as the piezoresistor, a low spring constant polyimide (PI) layer, and a thin silicon oxide (SiO) layer as the top and bottom passive layers, respectively. Excellent mechanical performances with the spring constant of 0.02128 N/m and the deflection sensitivity (∆V/V)/∆z of 1.03 × 10 nm were obtained. The output voltage fluctuation of a Wheatstone bridge, which consists of four piezoresistive microcantilevers, is less than 3 μV@3 V in a phosphate buffered saline (PBS) environment. A microcantilever aptasensor was then developed through functionalizing the microcantilevers with a ricin aptamer probe, and detections on ricin with concentrations of 10, 20, 50 and 100 ng/mL were successfully realized. A good specificity was also confirmed by using bovine serum albumin (BSA) as a blank control. The experiment results show that the Ti and PI-based microcantilever has great prospects for ultrasensitive biochemical molecule detections with high reliability and specificity.
本文介绍了一种具有低弹簧常数的压阻式微悬臂梁。该微悬臂梁以钛（Ti）作为压阻器、低弹簧常数的聚酰亚胺（PI）层以及分别作为顶部和底部钝化层的薄氧化硅（SiO）层制成。获得了优异的机械性能，弹簧常数为0.02128 N/m，挠度灵敏度（∆V/V）/∆z为1.03×10 nm。由四个压阻式微悬臂梁组成的惠斯通电桥在磷酸盐缓冲盐水（PBS）环境中的输出电压波动在3 V时小于3 μV。然后通过用蓖麻毒素适体探针功能化微悬臂梁开发了一种微悬臂梁适体传感器，并成功实现了对浓度为10、20、50和100 ng/mL的蓖麻毒素的检测。通过使用牛血清白蛋白（BSA）作为空白对照也证实了良好的特异性。实验结果表明，基于Ti和PI的微悬臂梁在超灵敏生化分子检测方面具有很大的前景，具有高可靠性和特异性。
