Laiou P.,University Pompeu Fabra |
Andrzejak R.G.,University Pompeu Fabra |
Andrzejak R.G.,Institute Of Bioenginyeria Of Catalonia Ibec
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2017
The understanding of interacting dynamics is important for the characterization of real-world networks. In general, real-world networks are heterogeneous in the sense that each node of the network is a dynamics with different properties. For coupled nonidentical dynamics symmetric interactions are not straightforwardly defined from the coupling strength values. Thus, a challenging issue is whether we can define a symmetric interaction in this asymmetric setting. To address this problem we introduce the notion of the coupling impact. The coupling impact considers not only the coupling strength but also the energy of the individual dynamics, which is conveyed via the coupling. To illustrate this concept, we follow a data-driven approach by analyzing signals from pairs of coupled model dynamics using two different connectivity measures. We find that the coupling impact, but not the coupling strength, correctly detects a symmetric interaction between pairs of coupled dynamics regardless of their degree of asymmetry. Therefore, this approach allows us to reveal the real impact that one dynamics has on the other and hence to define symmetric interactions in pairs of nonidentical dynamics. © 2017 American Physical Society.
Hoyo J.,Polytechnic University of Catalonia |
Torrent-Burgues J.,Polytechnic University of Catalonia |
Torrent-Burgues J.,Institute Of Bioenginyeria Of Catalonia Ibec |
Guaus E.,Polytechnic University of Catalonia
Journal of Colloid and Interface Science | Year: 2012
Ubiquinone and plastoquinone are two of the main electron and proton shuttle molecules in biological systems, and monogalactosyldiacylglycerol (MGDG) is the most abundant lipid in the thylakoid membrane of chloroplasts. Saturated MGDG, ubiquinone-10 (UQ) and MGDG:UQ mixed monolayers at the air/water interface have been studied using surface pressure-area isotherms and Brewster Angle Microscopy. Moreover, the transferred Langmuir-Blodgett films have been observed by Atomic Force Microscopy. The results show that MGDG:UQ mixtures present more fluid phase than pure MGDG, indicating a higher order degree for the later. It is also observed an important influence of UQ on the MGDG matrix before UQ collapse pressure and a low influence after this event, due to UQ expulsion from the MGDG matrix. This expulsion leads to a similar remaining UQ content for all the tested mixtures, indicating a limiting content of this molecule in the MGDG matrix at high surface pressures. The thermodynamic studies confirm the stability of the MGDG:UQ mixtures at low surface pressures, although presenting a non-ideal behaviour. Results point to consider UQ as a good candidate for studies of artificial photosynthesis. © 2012 Elsevier Inc.
Fumagalli L.,Institute Of Bioenginyeria Of Catalonia Ibec |
Fumagalli L.,University of Barcelona |
Esteban-Ferrer D.,Institute Of Bioenginyeria Of Catalonia Ibec |
Cuervo A.,CSIC - National Center for Biotechnology |
And 4 more authors.
Nature Materials | Year: 2012
Label-free detection of the material composition of nanoparticles could be enabled by the quantification of the nanoparticlesĝ™ inherent dielectric response to an applied electric field. However, the sensitivity of dielectric nanoscale objects to geometric and non-local effects makes the dielectric response extremely weak. Here we show that electrostatic force microscopy with sub-piconewton resolution can resolve the dielectric constants of single dielectric nanoparticles without the need for any reference material, as well as distinguish nanoparticles that have an identical surface but different inner composition. We unambiguously identified unlabelled ∼10 nm nanoparticles of similar morphology but different low-polarizable materials, and discriminated empty from DNA-containing virus capsids. Our approach should make the in situ characterization of nanoscale dielectrics and biological macromolecules possible. © 2012 Macmillan Publishers Limited. All rights reserved.
Darwish N.,University of Barcelona |
Darwish N.,Institute Of Bioenginyeria Of Catalonia Ibec |
Aragones A.C.,University of Barcelona |
Aragones A.C.,Institute Of Bioenginyeria Of Catalonia Ibec |
And 4 more authors.
Nano Letters | Year: 2014
Incorporating molecular switches as the active components in nanoscale electrical devices represents a current challenge in molecular electronics. It demands key requirements that need to be simultaneously addressed including fast responses to external stimuli and stable attachment of the molecules to the electrodes while mimicking the operation of conventional electronic components. Here, we report a single-molecule switching device that responds electrically to optical and chemical stimuli. A light pointer or a chemical signal can rapidly and reversibly induce the isomerization of bifunctional spiropyran derivatives in the bulk reservoir and, consequently, switch the electrical conductivity of the single-molecule device between a low and a high level. The spiropyran derivatives employed are chemically functionalized such that they can respond in fast but practical time scales. The unique multistimuli response and the synthetic versatility to control the switching schemes of this single-molecule device suggest spiropyran derivatives as key candidates for molecular circuitry. © 2014 American Chemical Society.
Campas M.,IRTA Ctra. de Poble Nou |
Garibo D.,IRTA Ctra. de Poble Nou |
Prieto-Simon B.,Institute Of Bioenginyeria Of Catalonia Ibec
Analyst | Year: 2012
This article gives an overview of the biosensors for the analysis of mycotoxins, marine toxins and cyanobacterial toxins, describing in depth the electrochemical biosensors that incorporate nanobiotechnological concepts. Firstly, it presents tailor-designed biomolecules, such as recombinant enzymes, recombinant antibody fragments and aptamers as novel biorecognition elements in biosensors. It also reviews the use of metallic nanoparticles (NPs) and carbon nanotubes (CNTs) aiming at improving the electrochemical transduction strategies. Finally, the exploitation of magnetic particles (MPs) as immobilisation carriers in flow-systems and the development of arrays are also described. The incorporation of these nanobiotechnological concepts provides with electrochemical biosensors with superior analytical performance in terms of specificity, sensitivity, stability and analysis time. This journal is © The Royal Society of Chemistry 1212.
Yang C.,CAS Changchun Institute of Applied Chemistry |
Yang C.,University of Chinese Academy of Sciences |
Lates V.,University of Perpignan |
Prieto-Simon B.,Institute Of Bioenginyeria Of Catalonia Ibec |
And 2 more authors.
Biosensors and Bioelectronics | Year: 2012
We report an aptasensor for biosensing of Ochratoxin A (OTA) using aptamer-DNAzyme hairpin as biorecognition element. The structure of this engineered nucleic acid includes the horseradish peroxidase (HRP)-mimicking DNAzyme and the OTA specific aptamer sequences. A blocking tail captures a part of these sequences in the stem region of the hairpin. In the presence of OTA, the hairpin is opened due to the formation of the aptamer-analyte complex. As a result, self-assembly of the active HRP-mimicking DNAzyme occurs. The activity of this DNAzyme is linearly correlated with OTA concentration up to 10. nM, showing a limit of detection of 2.5. nM. © 2011 Elsevier B.V.
Paytubi S.,University of Barcelona |
Aznar S.,University of Barcelona |
Madrid C.,University of Barcelona |
Balsalobre C.,University of Barcelona |
And 4 more authors.
Environmental Microbiology | Year: 2014
Summary: It is believed that the main role of plasmids that encode multiple antibiotic resistance is to confer their hosts the ability to survive in the presence of antimicrobial compounds. In the pathogenic bacterium Salmonella, plasmids of the incompatibility group HI1 account for a significant proportion of antibiotic resistance phenotypes. In this work, we show that plasmid R27 has a strong impact on the global transcriptome of SalmonellaTyphimurium strain SL1344 when cells grow at low temperature and enter the stationary phase. Down-regulated genes include pathogenicity islands, anaerobic respiration and metabolism determinants. Up-regulated genes include factors involved in the response to nutrient starvation, antimicrobial resistance, iron metabolism and the heat shock response. Accordingly, cells harbouring R27 are more resistant to heat shock than plasmid-free cells. The use of a different IncHI1 plasmid, pHCM1, provided evidence that these plasmids facilitate adaptation of Salmonella to environmental conditions outside their host(s). This is consistent with the fact that conjugative transfer of IncHI1 plasmids only occurs at low temperature. A significant number of the R27-dependent alterations in gene expression could be correlated with expression of a plasmid-encoded orthologue of the global modulator H-NS, which is up-regulated when cells grow at low temperature. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.
Gramse G.,Institute Of Bioenginyeria Of Catalonia Ibec |
Gramse G.,University of Barcelona |
Gomila G.,Institute Of Bioenginyeria Of Catalonia Ibec |
Gomila G.,University of Barcelona |
And 2 more authors.
Nanotechnology | Year: 2012
We present a systematic analysis of the effects that the microscopic parts of electrostatic force microscopy probes (the cone and cantilever) have on the electrostatic interaction between the tip apex and thick insulating substrates (thickness>100μm). We discuss how these effects can influence the measurement and quantification of the local dielectric constant of the substrates. We propose and experimentally validate a general methodology that takes into account the influence of the cone and the cantilever, thus enabling us to obtain very accurate values of the dielectric constants of thick insulators. © 2012 IOP Publishing Ltd.
Ma X.,Max Planck Institute for Intelligent Systems (Stuttgart) |
Jannasch A.,University of Tübingen |
Albrecht U.-R.,University of Tübingen |
Hahn K.,Max Planck Institute for Solid State Research |
And 5 more authors.
Nano Letters | Year: 2015
The development of synthetic nanomotors for technological applications in particular for life science and nanomedicine is a key focus of current basic research. However, it has been challenging to make active nanosystems based on biocompatible materials consuming nontoxic fuels for providing self-propulsion. Here, we fabricate self-propelled Janus nanomotors based on hollow mesoporous silica nanoparticles (HMSNPs), which are powered by biocatalytic reactions of three different enzymes: catalase, urease, and glucose oxidase (GOx). The active motion is characterized by a mean-square displacement (MSD) analysis of optical video recordings and confirmed by dynamic light scattering (DLS) measurements. We found that the apparent diffusion coefficient was enhanced by up to 83%. In addition, using optical tweezers, we directly measured a holding force of 64 ± 16 fN, which was necessary to counteract the effective self-propulsion force generated by a single nanomotor. The successful demonstration of biocompatible enzyme-powered active nanomotors using biologically benign fuels has a great potential for future biomedical applications. © 2015 American Chemical Society.
Ma X.,Max Planck Institute for Intelligent Systems (Stuttgart) |
Hahn K.,Max Planck Institute for Intelligent Systems (Stuttgart) |
Sanchez S.,Max Planck Institute for Intelligent Systems (Stuttgart) |
Sanchez S.,Catalan Institution for Research and Advanced Studies |
Sanchez S.,Institute Of Bioenginyeria Of Catalonia Ibec
Journal of the American Chemical Society | Year: 2015
We report on the synergy between catalytic propulsion and mesoporous silica nanoparticles (MSNPs) for the design of Janus nanomotors as active cargo delivery systems with sizes <100 nm (40, 65, and 90 nm). The Janus asymmetry of the nanomotors is given by electron beam (e-beam) deposition of a very thin platinum (2 nm) layer on MSNPs. The chemically powered Janus nanomotors present active diffusion at low H2O2 fuel concentration (i.e., <3 wt %). Their apparent diffusion coefficient is enhanced up to 100% compared to their Brownian motion. Due to their mesoporous architecture and small dimensions, they can load cargo molecules in large quantity and serve as active nanocarriers for directed cargo delivery on a chip. © 2015 American Chemical Society.