双幅正弦波激励频移法的压电石英传感器用于测定凝血时间

Frequency Shift Response of Piezoelectric Quartz Crystal with Double-Amplitude Excitation for Determining Coagulation Time

快速凝血检测技术在医学诊断领域具有重要应用价值,为了降低样本加入过程的扰动,文章开发了一种双幅激励的压电石英体新型凝血监测系统。该系统采用两种振幅正弦波分别对压电石英体进行激励,通过快速扫频技术测得其在不同激励电压下的谐振频率,所获得的频率差作为测量信号与液体粘度存在良好的线性关系。在血液凝固过程中,介质粘度会发生显著变化,压电石英体双幅频移信号可实现对血液凝固过程的实时动态监测。采用直径8 mm(电极直径3 mm)、基频10 MHz小型镀钛石英晶体设计出一次性微流控PQC检测片,成功用于微滴(15μL)毛细自动进样凝血过程的监测。对比传统单振幅激励PQC血凝监测系统,压电石英体双幅频移监测系统具有灵敏度高、重现性好的优势。使用该系统与商用电化学凝血仪分别对血样凝血时间进行了检测,结果显示两者数据具有很好的相关性。

The rapid coagulation detection technology plays an important role in medical diagnosis.In the paper,a new-type of piezoelectric quartz blood coagulation monitor with double amplitude-excitation was developed to reduce the disturbance during sample addition.In the present system,two amplitude sine waves were used to excite piezoelectric quartz respectively,and the resonant frequencies of the piezoelectric quartz under different excitation voltages were measured by fast frequency scanning technology.As a measurement signal,the change of frequency has a good linear relationship with the liquid viscosity.During the blood clotting,the viscosity of the medium changes dramatically,and the frequency shift signal of piezoelectric quartz with double amplitude excitation can realize real-time dynamic monitoring of blood coagulation process.A disposable microfluidic PQC test piece was designed by using a small titanic-plated quartz crystal with a diameter of 8 mm(electrode diameter of 3 mm)and the base frequency of 10 MHz,which was successfully used to monitor the coagulation process of microdroplet(15μL)capillary automatic injection.Compared with the traditional single amplitude excitation coagulation monitoring system,it has the advantages of high sensitivity and high precision.Furthermore,the coagulation time of the same samples was measured by the system and a commercial electrochemical coagulation instrument,and the results show that the two data have good correlation.