| Abstract |
In the first part of the present dissertation, we present a brief review on the field of biosensors with special emphasis to recent applications related with emerging health related topics. Starting from a brief historical review about the development of the first biosensors, the basic characteristics and concepts of biosensors are discussed. Novel biosensing concepts and categories have been developed recently, therefore a brief state-of-art review to the main types and biomedical applications, is presented. Finally, we introducing key developments in the field of acoustic/piezoelectric biosensors, and illustrating the wide area of biomolecule detection capabilities, along with the numerous advantages that are present on this type of sensors. In the second part of this study, it is presented the development of a low-cost and integrated surface acoustic wave (SAW) platform for the detection of molecular targets. The objective of this study is to establish a proof-of-concept application and addressing simultaneously several challenges related to technological and scientific topics. At the first step, we evaluated and explore the capabilities and the limitations of two widely used piezoelectric devices, specifically quartz and lithium tantalate. The latter presented extensive noise over the working frequency spectrum, while an attempt to minimize the spurious response was done. By testing the two different devices upon viscous loading with glycerol standards, quartz devices were found to be more sensitive over the different concentrations of glycerol concentrations. Concurrently with the evaluation of the acoustic devices, an attempt to use cost-effective, compact and open-source code instrumentation was done successfully. The next step towards the development of the platform was the re-use of acoustic devices and introducing alternative microfluidic designs to reduce the overall cost. Quartz devices were tested over a great number of experiments and different surface cleaning approaches were evaluated, indicating that rinsing and gently scrubbing the devices with a cotton bud or swab can prolong the device’s life up to 13 tests. Furthermore, experimental microfluidic gasket prototypes were made from common material and tested for their ability to maintain the acoustic signal and supplying the sensors surface with analytes without leaks. Finally, the developed setup and protocol was tested for its ability to detect molecular targets. For this reason, the acoustic response was monitored over different concentrations of Salmonella DNA LAMP amplicons, indicating that in our approach the SAW platform has a limit-of-detection of 100 bacterial cells. The results of the present study indicate that for the development of a portable acoustic platform several biological and engineering parameters should be optimized, thus, future research will focus mainly on alternative solutions to microfluidics, simplifying the instrumentation and increasing the sensitivity of the setup.
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Development of an acoustic platform for the molecular diagnosis at the point-of-care
