Color Engineering of Silicon Nitride Surfaces to Characterize the Polydopamine Refractive Index

A simple methodology to generate polydopamine (PDA) surfaces featured with color due to thin-film interference phenomena is presented. It is based on depositing ultra-thin films of polydopamine on a Si/Si 3 N 4 wafer that exhibits an interferential reflectance maximum right at the visible/UV boundary (∼400 nm). Therefore, a small deposit of PDA modifies the optical path, in such manner that the wavelength of the maximum of reflectance red shifts. Because the human eye is very sensitive to any change of the light spectral distribution at the visible region, very small film thickness changes (∼30 nm) are enough to notably modify the perceived color. Consequently, a controlled deposit of PDA, tune the color along the whole visible spectrum. Additionally, good quality of PDA deposits allowed us to determine the refractive index of polydopamine by ellipsometry spectroscopy. This data can be crucial in confocal skin microscopic techniques, presently used in diagnosis of skin tumors.Fil: Vega Moreno, Milena Amparo. Universidad de Salamanca; EspañaFil: Martín del Valle, Eva M.. Universidad de Salamanca; EspañaFil: Perez, Maximiliano Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Pecharromán, Carlos. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia de los Materiales de Barcelona; EspañaFil: Marcelo, Gema. Universidad de Salamanca; Españ

Simple Microcontact Printing Technique to Obtain Cell Patterns by Lithography Using Grayscale, Photopolymer Flexographic Mold, and PDMS

Microcontact printing using PDMS embossing tools and its variations have aroused the interest of a wide spectrum of research fields, hence the feasibility of defining micro and nanoscale patterns. In this work, we have proposed and demonstrated a novel lithography method based on grayscale patterns printed in a flexographic photopolymer mold and transferred to epoxy resin and a single PDMS stamp to obtain different microprint pattern structures. The geometry of the patterns can be modified by adjusting the layout and grayscale of the stamp patterns. The functionality of this contact printing methodology was validated by generating human induced pluripotent stem cells (hiPSC) patterns. These specific micropatterns can be very useful for achieving complex differentiation in cell lines such as hiPSC. Microfabrication through the new technique provides a promising alternative to conventional lithography for constructing complex aligned surfaces; these structures could be used as components of biological patterns or microfluidic devices.Fil: Gimenez, Rocio. Universidad Tecnológica Nacional; ArgentinaFil: Pérez Sosa, Camilo José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: Bourguignon, Natalia. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miriuka, Santiago Gabriel. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bhansali, Shekhar. University of Florida; Estados UnidosFil: Arroyo, Carlos R.. Universidad de Las Fuerzas Armadas; EcuadorFil: Debut, Alexis. Universidad de Las Fuerzas Armadas; EcuadorFil: Lerner, Betiana. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effect of butanol and salt concentration on solid-state nanopores resistance

The objective of this study was to demonstrate the possibility of using 1-butanol to detect in a reliable way the open pore current of pyramidal solid-state nanopores produced in silicon wafers. The nanopores were produced through controlled pore formation by neutralizing an etchant (KOH) with a strong acid (HCl). Since nanopores produced by this method have a larger depth than those made in nanometer thick membranes, they behave as nanochannels. As a consequence, the open pore current detection is more challenging. Thus, we report that low amounts of butanol considerably aid in the detection of the open pore current of nanopores.Fil: Vega, M.. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Granell, Pablo Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golmar, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wloka, C.. University of Groningen; Países BajosFil: Maglia, G.. University of Groningen; Países BajosFil: Dieguez, M.J.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Del Valle, E.M.. Universidad de Salamanca; EspañaFil: Lasorsa, Carlos Alberto. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A microfluidic study to investigate the effect of magnetic iron core-carbon shell nanoparticles on displacement mechanisms of crude oil for chemical enhanced oil recovery

The main objective of this work is to evaluate the effect of the simultaneous use of a surfactant mixture and magnetic iron core-carbon shell nanoparticles on oil recovery via a microfluidic study based on the rock-on-a-chip technology. The surfactant solution used for all experiments was prepared based on a field formulation and consisted of a mixture of a hydrophilic and a lipophilic surfactant. Magnetic iron core-carbon shell nanoparticles with a mean particle size of 60 nm and a surface area of 123 m2 g−1 were employed. The displacement experiments consisted of waterflooding, surfactant flooding and nanoparticle-surfactant flooding and were performed using PDMS (polydimethylsiloxane)-glass microdevices type random network. The characteristics and design of the microfluidic device allowed to emulate a mixed wettability of a porous medium. Then, the oil was displaced by injecting the solution at a constant injection rate, until steady-state conditions were obtained. Furthermore, the effect of three injection rates corresponding to 0.1 ft day−1, 1 ft day−1, and 10 ft day−1 was investigated. The increase in the injection rate favored the oil recovery percentage. In addition, for all injection rates, the oil recovery decreased in the following order: nanoparticle-surfactant flooding > surfactant flooding > waterflooding. The nanoparticle-surfactant system at the injection rate of 1.9 μL min−1 presented the highest oil recovery (i.e., 84%). Likewise, nanoparticle-surfactant flooding showed a more stable displacement front and consequently, the highest capillary number among the injection fluids. Oil recovery by waterflooding was the lowest among the evaluated systems due to the viscous fingering phenomena under different injection rates. In addition, it can be observed that for all injection rates, the presence of the surfactant mixture and nanoparticles reduce the viscous fingering effect. The results can be used to visually and quantitatively analyze the role of the simultaneous use of nanoparticles with surfactants in enhanced oil recovery processes.Fil: Betancur, Stefanía. Universidad Nacional de Colombia. Sede Medellín; Colombia. Universidad de Granada; EspañaFil: Olmos Carreno, Carol Maritza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Colombia. Sede Medellín; Colombia. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; ArgentinaFil: Franco, Camilo A.. Universidad Nacional de Colombia. Sede Medellin; ColombiaFil: Riazi, Masoud. Shiraz University; IránFil: Gallego, Jaime. Universidad Nacional de Colombia. Sede Medellin; Colombia. Universidad de Antioquia; ColombiaFil: Carrasco Marín, Francisco. Universidad de Granada; EspañaFil: Cortés, Farid B.. Universidad Nacional de Colombia. Sede Medellin; Colombi

Design and analysis of different models of microfluidic devices evaluated in enhanced oil recovery (EOR) assays

Microfluidic devices are a new platform for Enhanced Oil Recovery (EOR) assays. A successful oil recoveryin a reservoir can be different in another, hence the importance of a methodology for assessment prior toinjection. In the current study, micro and nanotechnology techniques were applied to develop EOR assays.The EOR chips simulated the phenomena occurred in micro-nano scale reservoirs. In general, the first step ofthe experiments corresponded to fill the microchannels with oil, then was injected water at constant flow rateuntil oil recovery ceases and finally was injected polymer or CDG. The recovery behaviors of the fluids werestudied by digital image analysis. Results allowed obtaining oil recovery for each evaluated fluid. Theoptimum configuration of the microchannels showed 80% of oil residual saturation after water injection.Keywords: EOR, poral volume, microgels and polymers, microfuidic devices.Fil: Rosero Yánez, Gustavo Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; ArgentinaFil: Peñaherrera Pazmiño, Ana Belén. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Olmos Carreno, Carol Maritza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; ArgentinaFil: Boschan, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Granell, Pablo Nicolás. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lasorsa, Carlos Alberto. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; ArgentinaFil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo. Grupo de Ingeniería de Recubrimientos Especiales y Nanotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentin

Single cell transfection of human-induced pluripotent stem cells using a dropletbased microfluidic system

Microfluidic tools have recently made possible many advances in biological and biomedical research. Research in fields such as physics, engineering, chemistry and biology have combined to produce innovation in microfluidics which has positively impacted diverse areas such as nucleotide sequencing, functional genomics, single-cell studies, single molecules assays and biomedical diagnostics. Among these areas, regenerative medicine and stem cells have benefited from microfluidics since these tools have had a profound impact on their applications. In this study, we present a high-performance droplet-based system for transfecting individual human-induced pluripotent stem cells. We will demonstrate that this system has great efficiency in single cells and captured droplets, like other microfluidic methods but with lower cost. Moreover, this microfluidic approach can be associated with the PiggyBac transposase-based system to increase its transfection efficiency. Our results provide a starting point for subsequent applications in more complex transfection systems, single-cell differentiation interactions, cell subpopulations and cell therapy, among other potential applications.Fil: Pérez Sosa, Camilo José. Fundacion P/la Lucha C/enferm.neurologicas Infancia. Instituto de Neurociencias. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Neurociencias.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sanluis Verdes, Anahi. Fundacion P/la Lucha C/enferm.neurologicas Infancia. Instituto de Neurociencias. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Neurociencias.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Waisman, Ariel. Fundacion P/la Lucha C/enferm.neurologicas Infancia. Instituto de Neurociencias. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Neurociencias.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lombardi, Antonella. Fundacion P/la Lucha C/enferm.neurologicas Infancia. Instituto de Neurociencias. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Neurociencias.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rosero, Gustavo. Universidad Tecnológica Nacional; ArgentinaFil: la Greca, Alejandro Damián. Fundacion P/la Lucha C/enferm.neurologicas Infancia. Instituto de Neurociencias. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Neurociencias.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bhansali, Shekhar. Florida International University; Estados UnidosFil: Bourguignon, Natalia. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Luzzani, Carlos Daniel. Fundacion P/la Lucha C/enferm.neurologicas Infancia. Instituto de Neurociencias. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Neurociencias.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miriuka, Santiago Gabriel. Universidad Tecnológica Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lerner, Betiana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional; Argentin

Cost-effective fabrication of photopolymer molds with multi-level microstructures for pdms microfluidic device manufacture

This paper describes a methodology of photopolymer mold fabrication with multi-level microstructures for polydimethylsiloxane (PDMS) microfluidic device manufacture. Multi-level microstructures can be performed by varying UVA exposure time and channel width. Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and profilometry techniques have been employed to characterize the molds. Multiple molds with multi-level microstructures can be formed in a unique piece. Overall height/depth of the structures reaches up to 677 μm and a minimum of 21 μm. The method provides several advantages such as reduction of fabrication time, multiple structures with diverse topologies, a great variety of depth and height in a single mold and low cost of fabrication. The effectiveness of multi-level microstructure fabrication was evaluated by constructing PDMS microfluidic devices for cell culture and proliferation.Fil: Olmos Carreno, Carol Maritza. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Penãherrera, Ana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Albert Ludwigs University of Freiburg; AlemaniaFil: Rosero Yánez, Gustavo Ivan. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Albert Ludwigs University of Freiburg; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vizuete, Karla. Universidad de Las Fuerzas Armadas; EcuadorFil: Ruarte, Darío. Albert Ludwigs University of Freiburg; AlemaniaFil: Follo, Marie. Albert Ludwigs University of Freiburg; AlemaniaFil: Vaca Mora, Andrea Vanessa. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arroyo, Carlos R.. Universidad de Las Fuerzas Armadas; EcuadorFil: Debut, Alexis. Universidad de Las Fuerzas Armadas; EcuadorFil: Cumbal Flores, Luis. Universidad de Las Fuerzas Armadas; EcuadorFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Florida International University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Florida International University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mertelsmann, Roland. Albert Ludwigs University of Freiburg; Alemani

Epoxy resin mold and PDMS microfluidic devices through photopolymer flexographic printing plate

Photopolymer flexographic printing plate is a new photopolymeric material used for microdevices fabrication. This work demonstrates that a photopolymer flexographic master mold can be used for the fabrication of PDMS (polydimethylsiloxane) microdevices by a multi-step manufacturing process. The methodology entails three main fabrication steps: (1) a photopolymer flexographic printing plate mold (FMold) is generated by UV exposure through a transparent film, (2) an epoxy resin mold (ERmold) is fabricated by transferring the features of the photopolymer mold and (3) a PDMS microdevice is manufactured from the epoxy resin mold. The characterization of the manufactured PDMS microdevices was performed using scanning electron microscopy (SEM) and profilometry. Results showed high accuracy in the replication of the profiles. To show the feasibility of the fabrication process a microdevice for microdroplet generation was designed, manufactured and tested. Hence, the manufacturing process described in this work provides an easy, robust, and low-cost strategy that facilitates the scaling-up of microfluidic devices without requiring any sophisticated equipment.Fil: Olmos Carreno, Carol Maritza. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vaca Mora, Andrea Vanessa. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rosero, Gustavo. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Peñaherrera Pazmiño, Ana Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Pérez Sosa, Camilo José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: de Sá Carneiro, Igor. Universidad Tecnológica Nacional. Facultad Regional Haedo; ArgentinaFil: Vizuete, Karla. Universidad de Las Fuerzas Armadas Espe; EcuadorFil: Arroyo, Carlos R.. Universidad de Las Fuerzas Armadas; EcuadorFil: Debut, Alexis. Universidad de Las Fuerzas Armadas; EcuadorFil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; ArgentinaFil: Cumbal, Luis. Universidad de Las Fuerzas Armadas; EcuadorFil: Lerner, Betiana. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentin

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements