Integrated Acoustofluidic Biosensors

Abstract

Acoustofluidics is an emerging field which utilizes acoustic waves to generate a multitude of microfluidic functionalities such as precise particle manipulation and liquid handling. Thanks to the high biocompatibility of ultrasound, this technique allows for gentle, noninvasive control over fragile biological material, making it ideally suited for applications in the life sciences and medicine. However, as the size of target particles decreases, it becomes increasingly challenging to generate enough force for reliable and precise manipulation. This dissertation showcases the development of two acoustofluidic platforms aimed at overcoming these challenges. In the first part, I will detail the development of an acoustofluidic centrifuge, which utilizes acoustic waves to drive the rotation of a microfluidic disk to separate exosomes from plasma with high yield and purity. The acoustofluidic disk is integrated with an amplification-free nanoplasmonic assay, creating a fully integrated sample-to-answer diagnostic assay for colorectal cancer with 95.8% sensitivity and 100% specificity. In the second part, I present an acoustofluidic picoinjector that enables precise and controllable injection of picoliter volume reagents or biological samples into microfluidic droplets, broadening the utility of droplet microfluidics for a myriad of applications in chemical and biological research such as single-cell analysis and nanoparticle synthesis.