压电生物传感器响应机制的声阻抗模型理论分析

Theoretical Analysis of Response Mechanisms of Piezoelectric Biosensors Based on Acoustic Impedance Model

基于声阻抗概念,建立起压电传感器响应机制的声阻抗模型,并引入与传感器负载剪切模量相关的声学校正因子,以表明传感器响应中的非质量效应.由此模型在一定近似条件下,对黏性液体,气/液相刚性和黏弹性薄膜等不同负载,分别导出相应的传感器响应方程,阐明了各种传感器响应机制的物理意义.另外在实际应用中可能存在摩擦,非均匀性和界面现象等干扰,但利用该声阻抗模型可望获取新信息、开拓新的应用.

An acoustic impedance model has been developed for analysis of response mechanisms of piezoelectric biosensors. The non-gravimetric effect in sensor＇s responses was defined by a parameter named acoustic correction factor relating to the mechanic property （shear modulus） of the sensor loading. Under some approximate conditions, response equations of piezoelectric biosensors were consequently derived for various loadings involving viscous liquid, rigid and viscoelastic films in gas and liquid phases. It was shown that the acoustic impedance of a sensor is pivotal to its biosensing. And through the universal model, various response mechanisms for piezoelectric biosensors could be physically clarified. Additionally, there would be some interference from factors such as friction, heterogeneity and interfacial phenomena in practical applications. However, new information would be provided by interpreting interferences with this model, and then new fields of application would be explored for piezoelectric biosensors.