'Scuola Normale Superiore - Edizioni della Normale'
Abstract
In the middle of the fourth industry revolution the necessity of intelligent manufacturing
and sensors plays an important role and pulls the research activity of
these days. In particular, smart objects able to sense, act, and behave within smart
environments are suitable tools to make this revolution evolve even further. More
efficient devices (in terms of costs, time and results) and data generated at all levels,
from industry production processes to people health monitoring, are desirable to
improve life quality. This goal would not be achieved without smart lab-on-chips
(LoCs) and sensors. Over the last decades surface acoustic wave (SAW) technology
has been studied and exploited to realize such smart devices. Main advantages
over standard microfluidic fluids manipulators and sensors are the high portability
of these devices, their all-electrical readout systems, their fabrication scalability
and their application versatility. In this context I developed my Ph.D. research
activity, by designing, fabricating, characterizing and testing new SAW-based devices
for LoC and sensing applications. I exploited both Rayleigh and Love SAWs
for this purpose, exploring different designs and working frequencies and obtaining
several encouraging results. With these SAW devices I demonstrated for the
first time that it is possible to enhance cells proliferation or gold functionalization
kinetics and efficiency. One of the main advantages of these devices is that they
are totally integrable with other ones and compatible with standard laboratories
protocols. Moving for the first time to ultra-high frequency (UHF), I realized SAW
biosensors with lower limit of detection than standard commercial acoustic sensors
and higher sensitivity and dynamic range than low-frequency SAW sensors. The
devices were tested with benchmark analytes and cells after being characterized in
details with microscopes, a laser Doppler vibrometer, a vector network analyzer,
an infrared camera and by means of micro-particle image velocimetry. Given these
results, the devices here presented are promising in the light of the development of
versatile, portable, and sensitive SAW-based devices for more efficient production
of functionalized materials and cells, smart diagnostics and monitoring of diseases,
food and air quality. They have the potential to contribute to the improvement of
daily life in the vision of the internet of things devices, for a smarter and more
efficient \u201cfuture\u201d world