Research Of Microfluidic Bioparticle Separation And Detection System Based On Surface Acoustic Wave And Lensless Imaging

The separation technology based on Standing Surfac Acoustic Wave(SSAW)has successfully achieved the sorting of particles and Circulating Tumor Cells(CTCs).The lensless imaging system can capture the images of micro objects such as particles or cells without focusing lens.In this thesis,we have designed and implemented a platform that integrates SSAW separation technology and lensless imaging.The mixed sample enters the SSAW domain through the microfluidic channel and achieves particle sorting of different volumes under the acoustic radiational force.A lensless imaging system captures the image near the output watershed of the microfluidic channel,and then the captured images are analyzed on PC.Through the research of the principle of SSAW-based sorting and lensless imaging,a uniform interdigital transducer(IDT)was designed to excite the surface acoustic wave.A 3-inlet and 2-outlet microfluidic channel was designed and optimized for the cross-section ratio of each inlet and outlet,and the particle trajectory in the absence of SSAW field was simulated in COMSOL.The protective glass and Bayer color filter of the image sensor were removed to increase the contrast of the captured original images.The relationship between the particle deviation trajectory,acoustic radiating force,and bonding angle was qualitatively analyzed,and a bonding angle of 5 degress was selected.Then the relationship between the optimal driving frequency and the S-parameters of the device was obtained by analyzing the relationship between the temperature of the PDMS channel and the driving frequency.Finally,the system components were assembled to form the SSAW-based bioparticle separation and lensless imaging detection platform.The performance of the SSAW-based bioparticle separation and lensless imaging detection platform was tested using a mixed polystyrene particles solution with the diameters of 5?m and 15 ?m.The relationship between the shift angle of the particle and driving power,and the separation-detection efficiency of 15 ?m at different flow rates and different driving powers were experimentally obtained.When the sample flow rate was 2?l/min and the driving power is 30 d Bm,the separation efficiency of 15 ?m reached about 95%.So this proposed platform has the potential to sort and count circulating the CTCs for POCT.