Search

[Abastract]: In the last decade, solution-gated graphene field effect transistors (GFETs) showed their versatility in the development of a miniaturized multiplexed platform for electrophysiological recordings and sensing. Due to their working mechanism, the surface functionalisation and immobilisation of receptors are pivotal to ensure the proper functioning of devices. Herein, we present a controlled covalent functionalisation strategy based on molecular design and electrochemical triggering, which provide a monolayer-like functionalisation of micro-GFET arrays retaining the electronic properties of graphenes. The functionalisation layer as a receptor was then employed as the linker for serotonin aptamer conjugation. The micro-GFET arrays display sensitivity toward the target analyte in the micromolar range in a physiological buffer (PBS 10 mM). The sensor allows the in-flow real-time monitoring of serotonin transient concentrations with fast and reversible responses.

Tomato (Solanum lycopersicum) is consumed worldwide as it isrich in vitamins and mineral salts. QfosfiK®is a biostimulant that increases yieldand improves fruit quality in different crops. The objective of the research was toevaluate the effect of foliar application of potassium phosphite on the growth andyield of tomato cultivars Paipai and Cid. The experiment was conducted undergreenhouse conditions at the Faculty of Agricultural Sciences, during 2019 on avertisol soil, in a randomized block design with 10 treatments and 4 replications. Thetreatments applied arose from the factorial arrangement of the two tomato cultivarsand five concentrations of potassium phosphite (0, 1.2, 1.5, 1.5, 1.8 and 2.1 L ha−1)prorated at transplanting, vegetative stage and beginning of the reproductive stage.Leaf number, leaf area index, net assimilation rate, berry yield and morphologicalcomponents: number of clusters and fruit were evaluated. The cultivar Cid had thebest yield due to the highest number of leaves, leaf area index, net assimilation rateand number of bunches plant−1. Regarding the doses, when 1.2 L ha−1was added,yield was optimized. The cultivar×dose interaction revealed that the highest fruityield was achieved by Cid (3.18 kg plant−1) when 1.2 L ha−1of product was added,while Paipai with 1.5 L ha−1produced 2.74 kg plant−1., El tomate (Solanum lycopersicum) se consume en él mundo, porquees rico en vitaminas y sales minerales. El QfosfiK®es un bioestimulante queincrementa el rendimiento y mejora la calidad de fruto en diferentes cultivos. Elobjetivo de la investigación fue evaluar el efecto de la aplicación foliar de fosfitode potasio sobre el crecimiento y rendimiento de los cultivares de tomate Paipaiy Cid. El experimento se realizó en condiciones de invernadero en la Facultad deCiencias Agrícolas, durante 2019 sobre un suelo vertisol, en un diseño de bloquesal azar con 10 tratamientos y 4 repeticiones. Los tratamientos aplicados surgierondel arreglo factorial de los dos cultivares de tomate y cinco concentraciones defosfito de potasio (0, 1,2, 1,5, 1,8 y 2,1 L ha−1) prorrateados en el trasplante, estadovegetativo e inicio de la etapa reproductiva. Se evaluó el número de hojas, el índicede área foliar, la tasa de asimilación neta, el rendimiento de baya y los componentesmorfológicos: número de racimos y frutos. El cultivar Cid tuvo el mejor rendimientodebido al mayor número de hojas, índice de área foliar, tasa de asimilación netay número de racimos planta−1. Respecto a las dosis, cuando se adicionó 1.2 Lha−1se optimizó la producción. La interacción cultivar×dosis reveló que la mayorcantidad de fruto la logró Cid (3.18 kg planta−1) cuando se añadieron 1.2 L ha−1deproducto, mientras qué, Paipai con 1.5 L ha−1produjo 2.74 kg planta−1.

Graphene solution-gated field-effect transistors (gSGFETs) offer high potential for chemical and biochemical sensing applications. Among the current trends to improve this technology, the functionalization processes are gaining relevance for its crucial impact on biosensing performance. Previous efforts are focused on simplifying the attachment procedure from standard multi-step to single-step strategies, but they still suffer from overreaction, and impurity issues and are limited to a particular ligand. Herein, a novel strategy for single-step immobilization of chemically modified aptamers with fluorenylmethyl and acridine moieties, based on a straightforward synthetic route to overcome the aforementioned limitations is presented. This approach is benchmarked versus a standard multi-step strategy using thrombin as detection model. In order to assess the reliability of the functionalization strategies 48-gSGFETs arrays are employed to acquire large datasets with multiple replicas. Graphene surface characterization demonstrates robust and higher efficiency in the chemical coupling of the aptamers with the single-step strategy, while the electrical response evaluation validates the sensing capability, allowing to implement different alternatives for data analysis and reduce the sensing variability. In this work, a new tool capable of overcome the functionalization challenges of graphene surfaces is provided, paving the way toward the standardization of gSGFETs for biosensing purposes.

In the last decade, solution-gated graphene field effect transistors (GFETs) showed their versatility in the development of a miniaturized multiplexed platform for electrophysiological recordings and sensing. Due to their working mechanism, the surface functionalisation and immobilisation of receptors are pivotal to ensure the proper functioning of devices. Herein, we present a controlled covalent functionalisation strategy based on molecular design and electrochemical triggering, which provide a monolayer-like functionalisation of micro-GFET arrays retaining the electronic properties of graphenes. The functionalisation layer as a receptor was then employed as the linker for serotonin aptamer conjugation. The micro-GFET arrays display sensitivity toward the target analyte in the micromolar range in a physiological buffer (PBS 10 mM). The sensor allows the in-flow real-time monitoring of serotonin transient concentrations with fast and reversible responses.

Organs-on-a-chip (OoC) are cell culture platforms that replicate key functional units of tissues in vitro. Barrier integrity and permeability evaluation are of utmost importance when studying barrier-forming tissues. Impedance spectroscopy is a powerful tool and is widely used to monitor barrier permeability and integrity in real-time. However, data comparison across devices is misleading due to the generation of a non-homogenous field across the tissue barrier, making impedance data normalization very challenging. In this work, we address this issue by integrating PEDOT:PSS electrodes for barrier function monitoring with impedance spectroscopy. The semitransparent PEDOT:PSS electrodes cover the entire cell culture membrane providing a homogenous electric field across the entire membrane making the cell culture area equally accountable to the measured impedance. To the best of our knowledge, PEDOT:PSS has never been used solely to monitor the impedance of cellular barriers while enabling optical inspection in the OoC. The performance of the device is demonstrated by lining the device with intestinal cells where we monitored barrier formation under flow conditions, as well as barrier disruption and recovery under exposure to a permeability enhancer. The barrier tightness and integrity, and the intercellular cleft have been evaluated by analyzing the full impedance spectrum. Furthermore, the device is autoclavable paving the way toward more sustainable OoC options.

Portal hypertension (PH) is a frequent and severe clinical syndrome associated with chronic liver disease. Considering the mechanobiological effects of hydrostatic pressure and shear stress on endothelial cells, we hypothesised that PH might influence the phenotype of liver sinusoidal endothelial cells (LSECs) during disease progression. The aim of this study was to investigate the effects of increased hydrodynamic pressure on LSECs and to identify endothelial-derived biomarkers of PH.

Mapping the entire frequency bandwidth of brain electrophysiological signals is of paramount importance for understanding physiological and pathological states. The ability to record simultaneously DC-shifts, infraslow oscillations (<0.1 Hz), typical local field potentials (0.1–80 Hz) and higher frequencies (80–600 Hz) using the same recording site would particularly benefit preclinical epilepsy research and could provide clinical biomarkers for improved seizure onset zone delineation. However, commonly used metal microelectrode technology suffers from instabilities that hamper the high fidelity of DC-coupled recordings, which are needed to access signals of very low frequency. In this study we used flexible graphene depth neural probes (gDNPs), consisting of a linear array of graphene microtransistors, to concurrently record DC-shifts and high-frequency neuronal activity in awake rodents. We show here that gDNPs can reliably record and map with high spatial resolution seizures, pre-ictal DC-shifts and seizure-associated spreading depolarizations together with higher frequencies through the cortical laminae to the hippocampus in a mouse model of chemically induced seizures. Moreover, we demonstrate the functionality of chronically implanted devices over 10 weeks by recording with high fidelity spontaneous spike-wave discharges and associated infraslow oscillations in a rat model of absence epilepsy. Altogether, our work highlights the suitability of this technology for in vivo electrophysiology research, and in particular epilepsy research, by allowing stable and chronic DC-coupled recordings.

The invention relates to a material with opto-mechanical behaviour characterized in that it comprises a cured elastomeric material layer with a corrugated surface, forming wrinkles in the form of ridges and valleys, and a plurality of metallic, dielectric or dielectric-metal coated nanostructures, embedded in the elastomeric material, that generate a Fabry-Perot elastic cavity enhanced by plasmons and or dielectric resonances, and modulated by the wrinkled surface; and a process to obtain it and its uses. Therefore, the present invention can be placed in the area of materials comprising plasmonic metamaterials and their applications.

[EN] The device limits the leakage current in an electronic system for recording electrophysiological signals, where the transducer element is an active device, the device comprising an active transducer (1), intended to contact a human tissue, connected to a transimpedance amplifier (2), and a first resistor (6) connected parallel to the transimpedance amplifier (2), an alternate voltage source (7) and a direct voltage source (8), both connected to the active transducer (1), a first capacitor (3) connected between the alternate voltage source (7) and the active transducer (1), a second resistor (4) connected between the direct voltage source (8) and the active transducer (1), parallel with the first capacitor (3) and the alternate voltage source (7), and a second capacitor (5), connected between the active transducer (1) and the transimpedance amplifier (2)., [FR] L'invention concerne un dispositif qui limite le courant de fuite dans un système électronique pour enregistrer des signaux électrophysiologiques, l'élément transducteur étant un dispositif actif, le dispositif comprenant un transducteur actif (1), destiné à entrer en contact avec un tissu humain, connecté à un amplificateur de transimpedance (2), et une première résistance (6) connectée en parallèle à l'amplificateur de transimpedance (2), une source de tension alternative (7) et une source de tension continue (8), toutes deux connectées au transducteur actif (1), un premier condensateur (3) connecté entre la source de tension alternative (7) et le transducteur actif (1), une deuxième résistance (4) connectée entre la source de tension continue (8) et le transducteur actif (1), parallèle au premier condensateur (3) et à la source de tension alternative (7), et un second condensateur (5), connecté entre le transducteur actif (1) et l'amplificateur de transimpédance (2).