High Frequency Acoustic On-chip Integration For Particle Characterizatioin And Manipulation In Microfluidics

The commercialized acoustic sensors in medicine have made great progress in the past decades.Otherwise,ultrasonic methods are particularly applicable to cell tests and medical diagnosis,because the acoustic technique can implement a gentle way to biological samples in a non-contact mode and characterize their stiffness.Benefit from this characteristic,scientists integrate acoustic modulus into microelectromechanical system(MEMS)devices for faster cost effectiveness,response time and mass production capability.In recent years,microfluidics platform has a booming development in clinical diagnosis and new drug screening,due to the unique advantages of fast-response,real time,high sensitivity,low cost detection and analysis.The acoustic-microfluidic chip technique is developed for on-chip specimen detection and manipulation,which combines both the advantages of ultrasonic technology and miniaturized platform.The highly integrated platform show great abilities for precise manipulation of tiny samples in biology(protein,cell and micro-organism in micrometer scale)and in-situdetection analysis.Currently,the acoustic-microfluidics applications are mainly two parts:acoustic sensors for signal processing and acoustic actuators for samples preparation.Nevertheless,the integration of these acoustic functions in silicon based Lab-on-chips requires specific technological developments,and up to now there is no high frequency bulk acoustic chips are capable for the integration of both acoustic sensors and actuators in the same device.The main objective of this work was to optimize acoustic energy transfer to a microfluidic channel in a frequency range between 500 MHz and 1000 MHz.To do that,the main technological developments achieved among others concern the coating of the guiding mirrors to avoid acoustic mode conversion and ZnO thick films sputtering for the fabrication of piezoelectric transducers.The developed system has been used for particles detection or concentration evaluation.Moreover,a first evaluation of fluids/particles actuation was demonstrated,along with temperature evaluation using ultrasound were achieved in microfluidic channels.