88 research outputs found

    BioMEMS

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    As technological advancements widen the scope of applications for biomicroelectromechanical systems (BioMEMS or biomicrosystems), the field continues to have an impact on many aspects of life science operations and functionalities. Because BioMEMS research and development require the input of experts who use different technical languages and come from varying disciplines and backgrounds, scientists and students can avoid potential difficulties in communication and understanding only if they possess a skill set and understanding that enables them to work at the interface of engineering and biosciences. Keeping this duality in mind throughout, BioMEMS: Science and Engineering Perspectives supports and expedites the multidisciplinary learning involved in the development of biomicrosystems. Divided into nine chapters, it starts with a balanced introduction of biological, engineering, application, and commercialization aspects of the field. With a focus on molecules of biological interest, the book explores the building blocks of cells and viruses, as well as molecules that form the self-assembled monolayers (SAMs), linkers, and hydrogels used for making different surfaces biocompatible through functionalization. The book also discusses: Different materials and platforms used to develop biomicrosystems Various biological entities and pathogens (in ascending order of complexity) The multidisciplinary aspects of engineering bioactive surfaces Engineering perspectives, including methods of manufacturing bioactive surfaces and devices Microfluidics modeling and experimentation Device level implementation of BioMEMS concepts for different applications. Because BioMEMS is an application-driven field, the book also highlights the concepts of lab-on-a-chip (LOC) and micro total analysis system (ÎŒTAS), along with their pertinence to the emerging point-of-care (POC) and point-of-need (PON) applications

    BioMEMS

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    As technological advancements widen the scope of applications for biomicroelectromechanical systems (BioMEMS or biomicrosystems), the field continues to have an impact on many aspects of life science operations and functionalities. Because BioMEMS research and development require the input of experts who use different technical languages and come from varying disciplines and backgrounds, scientists and students can avoid potential difficulties in communication and understanding only if they possess a skill set and understanding that enables them to work at the interface of engineering and biosciences. Keeping this duality in mind throughout, BioMEMS: Science and Engineering Perspectives supports and expedites the multidisciplinary learning involved in the development of biomicrosystems. Divided into nine chapters, it starts with a balanced introduction of biological, engineering, application, and commercialization aspects of the field. With a focus on molecules of biological interest, the book explores the building blocks of cells and viruses, as well as molecules that form the self-assembled monolayers (SAMs), linkers, and hydrogels used for making different surfaces biocompatible through functionalization. The book also discusses: Different materials and platforms used to develop biomicrosystems Various biological entities and pathogens (in ascending order of complexity) The multidisciplinary aspects of engineering bioactive surfaces Engineering perspectives, including methods of manufacturing bioactive surfaces and devices Microfluidics modeling and experimentation Device level implementation of BioMEMS concepts for different applications. Because BioMEMS is an application-driven field, the book also highlights the concepts of lab-on-a-chip (LOC) and micro total analysis system (ÎŒTAS), along with their pertinence to the emerging point-of-care (POC) and point-of-need (PON) applications

    Bio- und Umweltsensorik basierend auf organischer Optoelektronik

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    The integration of organic light emitting diodes (OLEDs) and organic photodetectors (OPDs) promises compact and low-cost hybrid integrated sensors for optical detection. The thermal evaporation-based device fabrication technique allows for all optical sensing elements being permanently aligned with a high degree of miniaturization, creating more portable, energy-efficient and multiplexing-capable devices; these may be easily combined with microfluidic units resulting in a minimal sample and reagent volume demand of the sensor. This dissertation deals in particular with the system design, development, characterization and deployment of a monolithic integrated sensor unit with 8 OLED and 8 OPD pixel pairs for different applications. The following work provides an extensive study of the system efficiency via ray tracing simulations, investigating crucial boundary conditions for efficient analyte detection. The proposed sensing unit contains OLED and OPD devices with an individual pixel size of 0.5mm × 0.5mm fabricated on a 12.5mm × 12.5mm glass substrate. The developed sensor system was successfully characterized and applied in a biosensing application by detecting fluorescence labelled single-stranded DNA (ssDNA) after forming the Förster resonance energy transfer (FRET) upon the hybridization of two ssDNA strands. This optoelectronic sensor has the potential to enable compact and low-cost fluorescence point-of-care (POC) devices for decentralised multiplex biomedical testing. Additionally, this sensing platform was deployed in environmental and agricultural applications to detect nutrients such as nitrite and nitrate. In this colorimetric application the popular Griess reaction was utilized to form the nitrite concentration dependent amount of azo dye, which absorbs light around 540nm

    Detection of fluorescence-labeled DNA with in-plane organic optoelectronic devices

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    We present a system efficiency analysis of a monolithic integrated organic optoelectronic unit for the detection of fluorescence labeled single-stranded DNA (ssDNA) for veterinary disease testing. The side-by-side integration of an organic light emitting diode (OLED) and an organic photodetector (OPD) with 0.5 mm by 0.5 mm device sizes has the potential to enable compact and low-cost fluorescence point-of-care (POC) devices for decentral multiplex biomedical testing. Here, we used two 6-FAM and BHQ1 labeled complementary ssDNA strands to form the Förster resonance transfer (FRET) upon the hybridization of the DNA. In this work we successfully show ssDNA hybridization sensing with samples diluted in TE buffer and investigate the detection of covalently bound 6-FAM-ssDNA on a glass surface for multiplex biomarker measurements

    Miniaturization of fluorescence sensing in optofluidic devices

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    International audienceSuccessful development of a micro-total-analysis system (ÎŒTAS, lab-on-a-chip) is strictly related to the degree of miniaturization, integration, autonomy, sensitivity, selectivity, and repeatability of its detector. Fluorescence sensing is an optical detection method used for a large variety of biological and chemical assays, and its full integration within lab-on-a-chip devices remains a challenge. Important achievements were reported during the last few years, including improvements of previously reported methodologies, as well as new integration strategies. However, a universal paradigm remains elusive. This review considers achievements in the field of fluorescence sensing miniaturization, starting from off-chip approaches, representing miniaturized versions of their lab counter-parts, continuing gradually with strategies that aim to fully integrate fluorescence detection on-chip, and reporting the results around integration strategies based on optical-fiber-based designs,optical layer integrated designs, CMOS-based fluorescence sensing, and organic electronics. Further successful development in this field would enable the implementation of sensing networks in specific environments that, when coupled to Internet of-Things (IoT) and artificial intelligence (AI), could provide real-time data collection and, therefore, revolutionize fields like health, environmental, and industrial sensing

    Grafeno em papel para dispositivos flexĂ­veis: sensores e OLEDs

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    The interest in flexible electronics has been growing considerably due to the possibility of products and devices with novel functionalities and improved comfort in their utilization. Graphene, with a combination of properties, is a natural candidate for these applications. Simultaneously, paper electronics is proving itself as a potentially significant branch of flexible electronics. Thus, it is particularly interesting to investigate the combination of these two materials for the development of novel and disruptive applications. This work covers the development of two types of flexible devices based on gra-phene and paper: physical and electrochemical sensors and organic light emit-ting diodes (OLEDs). In the context of sensors, one of the most recent additions to the family of graphene-based materials is explored: laser-induced graphene obtained from paper (paper-LIG), a graphene foam synthesized by a fast and low-cost process. The sensibility of paper-LIG to mechanical stimuli (strain and bending), as well as to humidity and temperature (in the latter case also shown for laser-induced graphene obtained from xylan, a biopolymer similar to cellulose) is demonstrated. The development of these devices is accompanied by a study of the influence of the synthesis parameters on the obtained material, comprising a sizeable contribution to the description of this material and its applications in the literature. Additionally, a non-enzymatic paper-LIG transductor for the electrochemical detection and quantification of uric acid is presented, demonstrating its response capability in real human urine samples, with a sensitivity of 0.363 ÎŒA cm⁻ÂČ ÎŒM⁻Âč and a linear range that covers the clinically relevant concentration range for this physiological parameter. In the scope of OLEDs, an optimized graphene synthesis process by chemical vapour deposition is presented, with the goal of using this single-layer graphene as a transparent electrode. The issue of high surface roughness typical of paper is addressed by the use of cellulose nanocrystal membranes and transparent rolling papers as flexible, biodegradable substrates, accompanied by the development of modified graphene film transfer and stacking approaches. The properties of this material are improved by thermal evaporation of MoO3, allowing the construction of OLEDs with 0.34% external quantum efficiency. The development of these devices not only contributes to reaffirm the vast potential of graphene, but also serves to introduce novel approaches in the context of low-cost and biodegradable flexible devices.O interesse na eletrĂłnica flexĂ­vel tem crescido consideravelmente devido ao de-senvolvimento de produtos e dispositivos com novas funcionalidades e maior conforto na utilização dos mesmos. O grafeno, com uma combinação Ășnica de propriedades, surge como um candidato natural para este tipo de aplicaçÔes. Simultaneamente, a eletrĂłnica em papel tem-se revelado como uma vertente potencialmente significativa na ĂĄrea da eletrĂłnica flexĂ­vel. Assim, torna-se parti-cularmente interessante investigar a combinação destes dois materiais para o desenvolvimento de novas e disruptivas aplicaçÔes. Este trabalho explora o desenvolvimento de dois tipos de dispositivos flexĂ­veis Ă  base de grafeno em papel: sensores fĂ­sicos e eletroquĂ­micos e dĂ­odos orgĂąnicos emissores de luz (OLEDs). No contexto dos sensores Ă© abordada uma das mais recentes adiçÔes Ă  famĂ­lia dos materiais Ă  base de grafeno: o grafeno induzido por laser obtido a partir do papel (paper-LIG), uma espuma de grafeno sintetizada por um processo rĂĄpido e de baixo custo. É demonstrada pela primeira vez a sensibilidade do paper-LIG a estĂ­mulos mecĂąnicos (distensĂŁo e flexĂŁo), bem como Ă  humidade e tempera-tura (neste Ășltimo caso tambĂ©m para o grafeno induzido por laser obtido a partir de xilana, um biopolĂ­mero semelhante Ă  celulose). O desenvolvimento destes dispositivos Ă© acompanhado por um estudo da influĂȘncia dos parĂąmetros de sĂ­n-tese no material obtido, constituindo uma contribuição significativa para a des-crição deste material e das suas aplicaçÔes na literatura. É ainda apresentado um transdutor nĂŁo-enzimĂĄtico de paper-LIG, para a deteção e quantificação ele-troquĂ­mica de ĂĄcido Ășrico, demonstrando a sua capacidade de resposta em amostras reais de urina humana, com uma sensibilidade de 0.363 ÎŒA ÎŒA cm⁻ÂČ ÎŒM⁻Âč e uma gama linear que abrange o intervalo de concentraçÔes clinicamente rele-vante para este parĂąmetro fisiolĂłgico. No Ăąmbito dos OLEDs, Ă© apresentado um processo otimizado de sĂ­ntese de grafeno monocamada por deposição quĂ­mica em fase vapor, com vista Ă  sua utilização como elĂ©trodo transparente. A questĂŁo da elevada rugosidade tipica-mente associada ao papel Ă© colmatada pelo uso de membranas de celulose nanocristalina e de mortalhas transparentes como substratos flexĂ­veis e biode-gradĂĄveis, acompanhado pelo desenvolvimento de tĂ©cnicas modificadas de transferĂȘncia e empilhamento de mĂșltiplas camadas de grafeno. As proprieda-des deste material sĂŁo melhoradas pela evaporação tĂ©rmica de MoO3, permi-tindo a construção de OLEDs com 0.34% de eficiĂȘncia quĂąntica externa. O desenvolvimento destes dispositivos nĂŁo sĂł contribui para reafirmar o vasto potencial do grafeno em conjugação com o papel, como serve tambĂ©m para introduzir novas abordagens no contexto de dispositivos flexĂ­veis de baixo custo e biodegradĂĄveis.Programa Doutoral em NanociĂȘncias e Nanotecnologi

    Development of a microfluidic device for gaseous formaldehyde sensing = Développement d\u27un dispositif microfluidique pour la détection de formaldéhyde à l\u27état gazeux

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    Formaldehyd (HCHO) ist eine chemische Verbindung, die bei der Herstellung einer großen Zahl von Haushaltsprodukten verwendet wird.Charakteristisch ist seine hohe FlĂŒchtigkeit aufgrund einer niedrigen Siedetemperatur (T=−19 ℃T = - 19\ ℃). Daher ist HCOH fast ĂŒberall als Luftschadstoff in InnenrĂ€umen vorhanden. Die Miniaturisierung analytischer Systeme zu Handheld-GerĂ€t hat das Potenzial, nicht nur effizientere, sondern auch empfindlichere Instrumente fĂŒr die EchtzeitĂŒberwachung dieses gefĂ€hrlichen Luftschadstoffs zu ermöglichen. Die vorliegende Doktorarbeit prĂ€sentiert die Entwicklung eines Mikrofluidik-GerĂ€ts fĂŒr die Erfassung von HCHO basierend auf der Hantzsch-Reaktion.Hierbei wurde der Schwerpunkt auf die Komponente fĂŒr Fluoreszenzdetektion gelegt. Es wurde eine umfangreiche Literaturrecherche durchgefĂŒhrt, die es erlaubt, den Stand der Technik auf dem Gebiet der Miniaturisierung des Fluoreszenzsensors zusammenzufassen. Auf Grund dieser Studie wurde ein modulares Fluoreszenzdetektionskonzept vorgeschlagen, das um einen CMOS-Bildsensor (CIS) herum entwickelt wurde. Zwei dreischichtige Fluidikzellenkonfigurationen (Konfiguration 1: Quarz - SU-8 3050 - Quarz und Konfiguration 2: Silizium - SU-8 3050 - Quarz) wurden in Betracht gezogen und parallel unter den gleichen experimentellen Bedingungen getestet. Die Verfahren der Mikrofabrikation der fluidischen Zellen wurden detailliert beschrieben, einschließlich des Integrationsprozesses der Standardkomponenten und der experimentellen Verfahren. Der CIS-basierte Fluoreszenzdetektor bewies seine LeistungsfĂ€higkeit, eine anfĂ€ngliche HCHO-Konzentration von 10 ”g/L vollstĂ€ndig in 3,5-Diacetyl-1,4-dihydrolutidin (DDL- derivatisiert) sowohl fĂŒr die Quarz- als auch fĂŒr die Silizium-Fluidikzellen zu detektieren. Beide Systemewiesenein Abfragevolumen von 3,5 ”L auf. Ein offensichtlich höheres Signal-Rausch-VerhĂ€ltnis (SNR) wurde fĂŒr die Silizium-Fluidzelle (SNRsilicon=6.1\text{SNR}_{\text{silicon}} = 6.1) im Vergleich zur Quarz-Fluidzelle (SNRquartz=4.9\text{SNR}_{\text{quartz}} = 4.9) beobachtet. Die VerstĂ€rkung der SignalintensitĂ€t in der Silizium-Fluidzelle ist wahrscheinlich auf den Silizium-Absorptionskoeffizienten bei der AnregungswellenlĂ€nge zurĂŒckzufĂŒhren,a(λabs=420 nm)=5∙104cm−1a\left( \lambda_{\text{abs}} = 420\ nm \right) = 5 \bullet 10^{4}\text{cm}^{- 1}. Dieser Koeffizient ist ungefĂ€hr fĂŒnfmal höher als der Absorptionskoeffizient bei der FluoreszenzemissionswellenlĂ€nge a(λem=515 nm)=9.25∙103cm−1a\left(\lambda_{\text{em}} = 515\ nm \right) = 9.25 \bullet 10^{3}\text{cm}^{- 1}. HCHO wird aufgrund seiner relativ hohen Konstanten fĂŒr das Henry-Gesetz sehr schnell in ein flĂŒssiges Reagenz aufgenommen. Somit hĂ€ngt die Auswahl des molekularen Einfangverfahrens (Schwallströmung, Ringströmung oder membranbasierte Strömungswechselwirkung) von derLeistungsfĂ€higkeit des Fluoreszenzdetektors ab. Ein vorlĂ€ufiges Konzept, das auf der Verwendung einer Gas-FlĂŒssigkeitsmembran-basierten Wechselwirkung zum stĂ€ndigen Abfangen des gasförmigen HCHO basiert, wurde eingefĂŒhrt. Hierzu wurden kompatible Materialien und Herstellungsmethoden identifiziert. DarĂŒber hinaus wurden CFD-Simulationen durchgefĂŒhrt, um die MikrokanallĂ€nge unter verschiedenen hydrodynamischen Bedingungen abzuschĂ€tzen, die fĂŒr eine vollstĂ€ndige HCHO-Derivatisierung erforderlich sind. Eine Verbesserung und Vereinfachung auf der Grundlage von sehrnempfindlichen Fluoreszenzdetektoren mit niedrigen Detektionsgrenzen könnte zukĂŒnftig basierend z. B. auf Schwallströmung oder Ringströmung möglich sein

    Emerging and Disruptive Next-Generation Technologies for POC: Sensors, Chemistry and Microfluidics for Diagnostics

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    Recently, the attention paid to self-care tests and the easy and large screening of a high number of people has dramatically increased. Indeed, easy and affordable tools for the safe management of biological fluids together with self-diagnosis have emerged as compulsory requirements in this time of the COVID-19 pandemic, to lighten the pressure on public healthcare institutions and thus limiting the diffusion of infections. Obviously, other kinds of pathologies (cancer or other degenerative diseases) also continue to require attention, with progressively earlier and more widespread diagnoses. The contribution to the development of this research field comes from the areas of innovative plastic and 3D microfluidics, smart chemistry and the integration of miniaturized sensors, going in the direction of improving the performances of in vitro diagnostic (IVD) devices. In our Special Issue, we include papers describing easy strategies to identify diseases at the point-of-care and near-the-bed levels, but also dealing with innovative biomarkers, sample treatments, and chemistry processes which, in perspective, represent promising tools to be applied in the field
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