Design of a Detachable Acoustically-Actuated Platform for Separation of Whole Blood and Nanoparticles
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Blood-based diagnostic tests have become a widespread paradigm for clinical disease diagnosis. Such tests are designed to detect small molecules in blood, which are indicative of a particular disease. Current blood-based diagnostic tests utilize specialized equipment, manual steps, and trained technicians. These factors limit the access of patients to testing. Lab-on-a-chip techniques, which enable handling of samples on the micron scale, have the potential to replace and simplify the current processes. In addition, sensitive optical assays that utilize functionalized nanoparticles have been developed for applications at the point-of-care. These assays require a consistent nanoparticle concentration. In this work, an acoustic platform to replace the first step in blood-based diagnostic assays, blood separation, is developed and tested for use with nanoparticle-based assays. The presented system uses a surface acoustic wave transducer integrated with a detachable microfluidic channel to achieve blood separation. The concept of a single-injection system, in which nanoparticles are mixed with an unprocessed sample, is tested. A standing wave generated by the transducer creates areas of high and low pressure across the microfluidic channel that cause displacement of blood components, based on size, from the sample stream to adjacent buffer fluid streams. The ability of this system to separate undiluted whole blood and nanoparticles is assessed. Fabrication of the standing surface acoustic wave transducer and microfluidic channel are described in detail. A detachable system is proposed to allow reuse of the transducer. Results from blood separation experiments using different transducer and channel designs are presented. To improve the transducer performance in experiments longer than several minutes, a temperature-regulation system was built. The first whole blood separation experiment using a detachable microchannel and standing surface acoustic waves is reported. Finally, the effect of the acoustic mechanism on functionalized nanoparticles is tested. The results indicate that a detachable acousto-fluidic system using surface acoustic waves may be used for effective whole blood separation when using temperature regulation. For maintenance of nanoparticle concentration and use of a single-injection system, the acoustic properties of the buffer must be tuned.
Wisniowiecki, Anna Marie (2018). Design of a Detachable Acoustically-Actuated Platform for Separation of Whole Blood and Nanoparticles. Master's thesis, Texas A & M University. Available electronically from