Sacrificial Adhesive Bonding: A Powerful Method For Fabrication Of Glass Microchips.

A new protocol for fabrication of glass microchips is addressed in this research paper. Initially, the method involves the use of an uncured SU-8 intermediate to seal two glass slides irreversibly as in conventional adhesive bonding-based approaches. Subsequently, an additional step removes the adhesive layer from the channels. This step relies on a selective development to remove the SU-8 only inside the microchannel, generating glass-like surface properties as demonstrated by specific tests. Named sacrificial adhesive layer (SAB), the protocol meets the requirements of an ideal microfabrication technique such as throughput, relatively low cost, feasibility for ultra large-scale integration (ULSI), and high adhesion strength, supporting pressures on the order of 5 MPa. Furthermore, SAB eliminates the use of high temperature, pressure, or potential, enabling the deposition of thin films for electrical or electrochemical experiments. Finally, the SAB protocol is an improvement on SU-8-based bondings described in the literature. Aspects such as substrate/resist adherence, formation of bubbles, and thermal stress were effectively solved by using simple and inexpensive alternatives.51327

An ultrasoft X-ray multi-microbeam irradiation system for studies of DNA damage responses by fixed- and live-cell fluorescence microscopy

Localized induction of DNA damage is a valuable tool for studying cellular DNA damage responses. In recent decades, methods have been developed to generate DNA damage using radiation of various types, including photons and charged particles. Here we describe a simple ultrasoft X-ray multi-microbeam system for high dose-rate, localized induction of DNA strand breaks in cells at spatially and geometrically adjustable sites. Our system can be combined with fixed- and live-cell microscopy to study responses of cells to DNA damage

Cross-Shaped Terahertz Metal Mesh Filters: Historical Review and Results

Terahertz frequencies experiments has motivated the development of new sources, detectors and optical components. Here we will present a review of THz bandpass filters ranging from 0.4 to 10 THz. We also demonstrate our fabrication process, simulations and experimental results

Simplified fabrication of integrated microfluidic devices using fused deposition modeling 3D printing

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESMicrofluidic devices based on polydimethylsiloxane shown a plethora of experimental possibilities due to good transparency, flexibility and ability to adhere reversibly and irreversibly to distinct materials. Though PDMS is a milestone in microfluidic developments, its cost and handling directed the field to search for new options. 3D printing technology nowadays starts a revolution offering materials and possibilities that can contribute positively to current methodologies. Here we explored the fused deposition modeling 3D printing technique to obtain integrated, transparent and sealed microchannels made with polylactic acid, a cheap alternative material to set up microfluidic systems. Using a home-made 3D printer, devices could be assembled in a simplified process, enabling the integration of different materials such as paper, glass, wire and polymers within the microchannel. To demonstrate the efficacy of this approach, a 3D-printed electronic tongue sensor was built, enabling the distinction of basic tastes below the human threshold. (C) 2016 Elsevier B.V. All rights reserved.Microfluidic devices based on polydimethylsiloxane shown a plethora of experimental possibilities due to good transparency, flexibility and ability to adhere reversibly and irreversibly to distinct materials. Though PDMS is a milestone in microfluidic developments, its cost and handling directed the field to search for new options. 3D printing technology nowadays starts a revolution offering materials and possibilities that can contribute positively to current methodologies. Here we explored the fused deposition modeling 3D printing technique to obtain integrated, transparent and sealed microchannels made with polylactic acid, a cheap alternative material to set up microfluidic systems. Using a home-made 3D printer, devices could be assembled in a simplified process, enabling the integration of different materials such as paper, glass, wire and polymers within the microchannel. To demonstrate the efficacy of this approach, a 3D-printed electronic tongue sensor was built, enabling the distinction of basic tastes below the human threshold.2423540FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES2014/03691-7Sem informaçãoSem informaçã

Microfluidic electronic tongue

Fast, simple inspection of liquids such as coffee, wine and body fluids is highly desirable for food, beverage and clinical analysis. Electronic tongues are sensors capable of performing quantitative and qualitative measurements in liquid substances using multivariate analysis tools. Earlier attempts to fulfil this task using only a few drops (microliters) of sample did not yield rational results with non-electrolytes e.g. sucrose (sweetness). We report here the fabrication and testing of a microfluidic e-tongue able to distinguish electrolytes from non-electrolytes, covering also the basic tastes relevant to human gustative perception. The sensitivity of our device is mainly attributed to the ultrathin nature of an array formed by non-selective sensing units. The electronic tongue is composed of an array of sensing units designed with a microchannel stamped in a poly( dimethylsiloxane) (PDMS) matrix and sealed onto gold interdigitated electrodes (IDEs). The IDEs are then coated in situ with a 5-bilayer film deposited by the layer-by-layer (LbL) technique. The cationic layer is derived from polyallylamine chloride (PAH). The anionic layer is either poly(3,4-ethylenedioxythiophene)-poly( styrenesulfonate) PEDOT:PSS, polypyrrole or nickel tetrasulfonated phthalocyanine. When compared to a conventional electronic tongue our system is three times faster and requires only microliters of sample. Applying Principal Component Analysis to the data yields a high correlation for all substances tested. This microfluidic e-tongue has the potential for producing low-cost, easily integrated, multi-functional sensor for food, beverages, in addition to clinical and environmental applications.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Poole-Frenkel emission on functionalized, multilayered-packed reduced graphene oxide nanoplatelets

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORThe unique electronic, mechanical and optical properties of graphene make it a remarkable 2D material, widely explored in a plethora of applications. However, graphene zero-bandgap and the production of defect-free pristine graphene in large areas still limit some applications. To circumvent these issues, graphene-derived 2D materials have arisen as attractive candidates for low-dimensional systems, which requires a better comprehension of their properties. Here, we report a detailed investigation of the conduction mechanisms of two functionalized reduced graphene oxides (rGOs) nanoplatelets, named GPAH and GPSS. The functionalized rGO nanoplatelets were bottom-up assembled via the layer-by-layer technique, enabling molecular-level thickness control of nanostructures with well-defined composition and structure. For the reported multilayered GPAH/GPSS films the charge carriers followed Mott's law, presenting a typical conduction behavior of 2D systems described by the Poole-Frenkel model. The multilayered GPAH/GPSS nanostructure presented a conductivity of 10(-4)S cm(-1), optical bandgap of similar to 3.3 eV and a relative dielectric permittivity (epsilon(r)) of 6.4. Temperature-dependent I-V measurements indicated a strong variation of er below the critical temperature (T-C = 237 K), associated with a high dipole reorientation in the formed GPAH/GPSS nanostructure. All these characteristics make the GPAH/GPSS nanocomposite attractive for graphene-oriented applications, such as electronic devices.295019FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIOR2014/03691-72014/25979-2sem informaçãosem informaçã

Information Visualization and Feature Selection Methods Applied to Detect Gliadin in Gluten-Containing Foodstuff with a Microfluidic Electronic Tongue

The fast growth of celiac disease diagnosis has sparked the production of gluten-free food and the search for reliable methods to detect gluten in foodstuff. In this paper, we report on a microfluidic electronic tongue (e-tongue) capable of detecting trace amounts of gliadin, a protein of gluten, down to 0.005 mg kg^–1 in ethanol solutions, and distinguishing between gluten-free and gluten-containing foodstuff. In some cases, it is even possible to determine whether gluten-free foodstuff has been contaminated with gliadin. That was made possible with an e-tongue comprising four sensing units, three of which made of layer-by-layer (LbL) films of semiconducting polymers deposited onto gold interdigitated electrodes placed inside microchannels. Impedance spectroscopy was employed as the principle of detection, and the electrical capacitance data collected with the e-tongue were treated with information visualization techniques with feature selection for optimizing performance. The sensing units are disposable to avoid cross-contamination as gliadin adsorbs irreversibly onto the LbL films according to polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) analysis. Small amounts of material are required to produce the nanostructured films, however, and the e-tongue methodology is promising for low-cost, reliable detection of gliadin and other gluten constituents in foodstuff