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Identifier 000419807
Title Integrated microfluidic devices for rapid DNA amplification applicable to diagnostics and pathogen detection in food
Alternative Title Ολοκληρωμένες μικρορευστονικές διατάξεις ταχείας ενίσχυσης DNA με εφαρμογή σε διαγνωστικά και ανίχνευση παθογόνων σε τρόφιμα
Author Κάπρου, Γεωργία Δ.
Thesis advisor Γκιζελή, Ηλέκτρα
Reviewer Τσερέπη, Αγγελική
Βόντας, Ιωάννης
Abstract This PhD thesis focuses on the development of low cost and low energy consumption DNA amplification Printed Circuit Board (PCB)-based microdevices, enabling their use even in low resource settings, suitable for integration in Lab-on-a-Chip (LoC) platforms addressing pathogen detection employed in food safety, medical diagnostics, and environmental monitoring. Both high integrability and low fabrication cost were achieved by selecting PCB as the main substrate and developing fabrication processes compatible with PCB manufacturing. Besides the integration of microfluidics with electronic components such as sensors, PCB allows also the integration of copper microheaters providing the thermal zones necessary for DNA amplification. Therefore, low-cost, mass production amenable DNA amplification microdevices are feasible with the implementation of commercially available, PCB compatible materials and processes proposed for the fabrication of the microdevices within the established PCB industry, thus addressing one of the microfluidics bottlenecks which is their commercialization. In this thesis, both static and continuous flow DNA amplification microdevices were fabricated and validated employing numerous amplification (isothermal and non-isothermal) methods such as Polymerase Chain Reaction (PCR), Recombinase Polymerase Amplification (RPA), Helicase Dependent Amplification (HDA) and Loop-mediated Amplification (LAMP). Amplification protocols much faster than in conventional thermocyclers (up to more than 20 times) were demonstrated within the developed DNA amplification microdevices, from 2 min –one of the fastest ever reported- to 30 min. The design of the DNA microdevices (based on numerical calculations) assures also low energy consumption (324 J to 4320 J) which can be translated to the independent operation/performance of 65 to 1000 reactions (depending on the DNA amplification method) with a regular power bank of 10.000 mAh (9V). Such DNA amplification microdevices were for the first time integrated with Surface Acoustic Wave (SAW) biosensors; a LoC platform based on SAW acoustic detection is demonstrated in this work, performing cell capturing, lysis and DNA amplification on a single chip for the detection of viable Salmonella cells (stemming from artificially spiked milk) within less than 6 h. In parallel, further improvement of the LoC platform was achieved by investigating methods for wall passivation to prevent biomolecule adsorption on the surface of the microfluidic devices and promote DNA amplification. Bovine Serum Albumin (BSA) 1% proved to better passivate wall surfaces by inhibiting biomolecule adsorption. Similarly, surface functionalization of acoustic sensors (Quartz Crystal Microbalance with Dissipation, QCM-D) for selective DNA binding in complex samples was investigated, paving the way to employ the developed platform with complex matrices. The use of a blocking buffer prior passing the sample improves the discrimination potential between contaminated and control samples when Avidin-Biotin conjugate detection is used.
Language English
Subject Acoustic biosensors
Point of care diagnostics
Ακουστικοί αισθητήρες
Επιτόπια διαγνωστικά
Μικροεργαστήριο σε ψηφίδα
Issue date 2018-11-08
Collection   Faculty/Department--Faculty of Sciences and Engineering--Department of Biology--Doctoral theses
  Type of Work--Doctoral theses
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