| dc.description.abstract | 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. | en |
