液体中微悬臂传感器共振检测技术的研究

Study on Resonance Frequency Detecting of Microcantilever Sensor in Liquid

讨论了微悬臂生化传感器在动态模式下的工作原理,针对在液体环境中阻尼增大、微悬臂共振品质因素下降的问题,设计了一个正反馈电路,使得微悬臂在液体中能够稳定在其固有频率上自激振荡,从而简便地测出微悬臂传感器在吸附分析物之后的频率变化。实验中将黄金Au溅射于微悬臂上,每次溅射的厚度为1 nm,等效质量约为0.04272 ng,溅射12次,测得去离子水中微悬臂的频率随溅射的Au质量的增加,约以-10.089 Hz/pg的线性趋势下降,微悬臂对附加质量的检测分辨率提高了约200倍,达到1 pg。

The principle of microcantilever biochemical sensors was discussed in this work.When the microcantilever works in liquid,the damp is increased to result in dropping of its quality factor.So,a positive feedback circuit was designed to make the microcantilever oscillate by itself at a definite frequency so that the frequency shift caused by mass adsorption on the microcantilever can be measured easily.When the frequency shift was measured,an Au film was deposited on the microcantilever and the thickness and effective mass of the Au film deposited one time were 1nm and 0.04272 ng,respectively.After the Au film was deposited twelve times,the results indicate that the frequency of the microcantilever is linearly reduced about 10.089Hz per pg with increment of mass of Au and the resolution power is increased about 200 times and its mass resolution is 1pg.