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Projeto de investigação
New Generation of Digital Microfluidics for Nucleic Acid Amplification
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Digital Microfluidics-Powered Real-Time Monitoring of Isothermal DNA Amplification of Cancer Biomarker
Publication . Coelho, Beatriz Jorge; Veigas, Bruno; Bettencourt, Luís; Águas, Hugo; Fortunato, Elvira; Martins, Rodrigo; Baptista, Pedro V.; Igreja, Rui; DCM - Departamento de Ciência dos Materiais; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; DCV - Departamento de Ciências da Vida; UCIBIO - Applied Molecular Biosciences Unit; MDPI - Multidisciplinary Digital Publishing Institute
We introduce a digital microfluidics (DMF) platform specifically designed to perform a loop-mediated isothermal amplification (LAMP) of DNA and applied it to a real-time amplification to monitor a cancer biomarker, c-Myc (associated to 40% of all human tumors), using fluorescence microscopy. We demonstrate the full manipulation of the sample and reagents on the DMF platform, resulting in the successful amplification of 90 pg of the target DNA (0.5 ng/µL) in less than one hour. Furthermore, we test the efficiency of an innovative mixing strategy in DMF by employing two mixing methodologies onto the DMF droplets—low frequency AC (alternating current) actuation as well as back-and-forth droplet motion—which allows for improved fluorescence readouts. Fluo-rophore bleaching effects are minimized through on-chip sample partitioning by DMF processes and sequential droplet irradiation. Finally, LAMP reactions require only 2 µL volume droplets, which represents a 10-fold volume reduction in comparison to benchtop LAMP.
Hybrid Digital-Droplet Microfluidic Chip for Applications in Droplet Digital Nucleic Acid Amplification
Publication . Coelho, Beatriz J.; Neto, Joana P.; Sieira, Bárbara; Moura, André T.; Fortunato, Elvira; Martins, Rodrigo; Baptista, Pedro V.; Igreja, Rui; Águas, Hugo; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UCIBIO - Applied Molecular Biosciences Unit; DCV - Departamento de Ciências da Vida; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; MDPI - Multidisciplinary Digital Publishing Institute
Microfluidic-based platforms have become a hallmark for chemical and biological assays, empowering micro- and nano-reaction vessels. The fusion of microfluidic technologies (digital microfluidics, continuous-flow microfluidics, and droplet microfluidics, just to name a few) presents great potential for overcoming the inherent limitations of each approach, while also elevating their respective strengths. This work exploits the combination of digital microfluidics (DMF) and droplet microfluidics (DrMF) on a single substrate, where DMF enables droplet mixing and further acts as a controlled liquid supplier for a high-throughput nano-liter droplet generator. Droplet generation is performed at a flow-focusing region, operating on dual pressure: negative pressure applied to the aqueous phase and positive pressure applied to the oil phase. We evaluate the droplets produced with our hybrid DMF–DrMF devices in terms of droplet volume, speed, and production frequency and further compare them with standalone DrMF devices. Both types of devices enable customizable droplet production (various volumes and circulation speeds), yet hybrid DMF–DrMF devices yield more controlled droplet production while achieving throughputs that are similar to standalone DrMF devices. These hybrid devices enable the production of up to four droplets per second, which reach a maximum circulation speed close to 1540 µm/s and volumes as low as 0.5 nL.
Parylene C as a Multipurpose Material for Electronics and Microfluidics
Publication . Coelho, Beatriz J.; Pinto, Joana V.; Martins, Jorge; Rovisco, Ana; Barquinha, Pedro; Fortunato, Elvira; Baptista, Pedro V.; Martins, Rodrigo; Igreja, Rui; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); UCIBIO - Applied Molecular Biosciences Unit; DCV - Departamento de Ciências da Vida; UNINOVA-Instituto de Desenvolvimento de Novas Tecnologias; MDPI - Multidisciplinary Digital Publishing Institute
Poly(p-xylylene) derivatives, widely known as Parylenes, have been considerably adopted by the scientific community for several applications, ranging from simple passive coatings to active device components. Here, we explore the thermal, structural, and electrical properties of Parylene C, and further present a variety of electronic devices featuring this polymer: transistors, capacitors, and digital microfluidic (DMF) devices. We evaluate transistors produced with Parylene C as a dielectric, substrate, and encapsulation layer, either semitransparent or fully transparent. Such transistors exhibit steep transfer curves and subthreshold slopes of 0.26 V/dec, negligible gate leak currents, and fair mobilities. Furthermore, we characterize MIM (metal–insulator–metal) structures with Parylene C as a dielectric and demonstrate the functionality of the polymer deposited in single and double layers under temperature and AC signal stimuli, mimicking the DMF stimuli. Applying temperature generally leads to a decrease in the capacitance of the dielectric layer, whereas applying an AC signal leads to an increase in said capacitance for double-layered Parylene C only. By applying the two stimuli, the capacitance seems to suffer from a balanced influence of both the separated stimuli. Lastly, we demonstrate that DMF devices with double-layered Parylene C allow for faster droplet motion and enable long nucleic acid amplification reactions.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
OE
Número da atribuição
SFRH/BD/132904/2017