Imidazole-based ionogel as room temperature benzene and formaldehyde sensor

A room temperature benzene and formaldehyde gas sensor system with an ionogel as sensing material is presented. The sensing layer is fabricated employing poly(N-isopropylacrylamide) polymerized in the presence of 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid onto gold interdigitated electrodes. When the ionogel is exposed to increasing formaldehyde concentrations employing N2as a carrier gas, a more stable response is observed in comparison to the bare ionic liquid, but no difference insensitivity occurs. On the other hand, when air is used as carrier gas the sensitivity of the system towards formaldehyde is decreased by one order of magnitude. At room temperature, the proposed sensor exhibited in air higher sensitivities to benzene, at concentrations ranging between 4 and 20 ppm resulting, in a limit of detection of 47 ppb, which is below the standard permitted concentrations. The selectivity of the IL towards HCHO and C6H6is demonstrated by the absence of response when another IL is employed. Humidity from the ambient air slightly affects the resistance of the system proving the protective role of the polymeric matrix. Furthermore, the gas sensor system showed fast response/recovery times considering the thickness of the material, suggesting that ionogel materials can be used as novel and highly efficient volatile organic compounds sensors operating at room temperature.This work was supported by the Ministry of Economy and Competitiveness (MINECO) of Spain under the TEMIN-++AIR programs. N.G.-G. was supported by a PhD fellowship from the University of Navarra. F. B.-L. acknowledges the funding support from Gobierno de España, Ministerio de Economía y Competitividad, with Grant No. BIO2016-80417-P, and Gobierno Vasco Dpto. Educación for the consolidation of the research groups (IT1271-19)

Graphene memristors based on humidity-mediated reduction of graphene oxide

Memristors have emerged as promising devices for neuromorphic applications, particularly as synaptic weight. Graphene oxide, a partially oxidised and electrically insulating form of graphene, has been employed in metal/insulator/metal devices, where resistance switching based on the filamentary growth of the contacting metals has been demonstrated. Here we demonstrate an alternative highly reproducible resistance switching mechanism based on solid-state reduction of GO thin-films mediated by adsorbed water. It is shown that distinguishable and highly stable resistance states can be controllably realised in graphene oxide metal/insulator/metal devices. We have unravelled the growth mechanism and determined the growth kinetic of reduced graphene oxide, which enables a deterministic way to tune the resistance in GO devices. The demonstration of highly reproducible memristors based on graphene oxide crossbar devices is very promising for the realisation of low-cost and environmentally benign solution-processable neuromorphic synaptic weight

Graphene memristors based on humidity-mediated reduction of graphene oxide

Memristors have emerged as promising devices for neuromorphic applications, particularly as synaptic weight. Graphene oxide, a partially oxidised and electrically insulating form of graphene, has been employed in metal/insulator/metal devices, where resistance switching based on the filamentary growth of the contacting metals has been demonstrated. Here we demonstrate an alternative highly reproducible resistance switching mechanism based on solid-state reduction of GO thin-films mediated by adsorbed water. It is shown that distinguishable and highly stable resistance states can be controllably realised in graphene oxide metal/insulator/metal devices. We have unravelled the growth mechanism and determined the growth kinetic of reduced graphene oxide, which enables a deterministic way to tune the resistance in GO devices. The demonstration of highly reproducible memristors based on graphene oxide crossbar devices is very promising for the realisation of low-cost and environmentally benign solution-processable neuromorphic synaptic weight

Understanding the behavior of stimuli-response ionogels for microfluidic applications

Part of special issue: Proceedings of the 30th anniversary Eurosensors Conference – Eurosensors 2016, 4-7. Sepember 2016, Budapest, HungaryElectrochemical Impedance Spectroscopy (EIS) studies of two different ionogels (IOs) are performed using gold interdigitated electrodes (Au-IDEs). Poly(N isopropylacrylamide) (pNIPAAM) is polymerized in the presence of two ionic liquids (ILs), ethyl- 3-methylimidazolium ethyl sulfate [C2mIm][EtSO2] (1) or trihexyltetradecyl-phosphonium dicyanamide [P6,6,6,14][DCA] (2). The Nyquist diagrams of the IOs reflect significant differences due to their polarity and porosity dissimilarities. This fact is supported with the study of the diffusion of water through the polymer matrix, which is faster for IO-1, the most porous IO. Moreover, the ability of IO-1 and IO-2 to conduct current is measured and the sheet resistance of IO-2 is two orders of magnitude higher than IO-1. Finally, the swelling/drying properties of the IOs are monitored exposing them to several vacuum and rehydration cycles. The Nyquist plot of IO-1 shows faster diffusion and recovery of the original properties. Both hydrophilicity and porosity are in the basis of these results.This work was supported by the Basque Government under the Etortek Program (Grant No. IE14–391). N.G-G. was supported by a PhD fellowship from the University of Navarra

Manipulation of Fluid Flow Direction in Microfluidic Paper-Based Analytical Devices with an Ionogel Negative Passive Pump

Microfluidic paper-based analytical devices (microPADs) are a relatively new group of analytical tools thatrepresent an innovative low-cost platform technology for fluid handling and analysis. Nonetheless, microPADs lack in the effective handling and controlling of fluids, which leads to a main drawback for their reproducibility in large volumes during manufacturing, their transition from the laboratory into the marketand thus accessibility by end-users. Herein we investigate the applicability of ionogel materials basedon a poly(N-isopropylacrylamide) gel with the 1-ethyl 3-methylimidazolium ethyl sulfate ionic liquidas fluid flow manipulator in microPADs using the ionogel as a negative passive pump to control the flowdirection in the device. A big challenge undertook by this contribution is the integration of the ionogel materials into the microPADs. Finally, the characterisation and the performance of the ionogel as a negative passive pump is demonstrated.The project was carried out with the support of the Ramón y Cajal programme (Ministerio de Economía y Competitividad). FBL thanks to the European Union’s Seventh Framework Programme(FP7) for Research, Technological Development and Demonstration under grant agreement no. 604241 and the Gobierno Vasco, Dpto. Industria, Innovación, Comercio y Turismo under ELKARTEKKK-2015/00088. FBL and TA personally acknowledge Marian M.de Pancorbo for letting them to use her laboratory facilities at UPV/EHU. MCMM acknowledges the Basque Government under theEtortek Program (Grant No. IE14-391) and Dr Seifert for the use ofhis laboratory facilities. NG-G work was supported by a PhD fellowship from the University of Navarra. Authors also acknowledge Adhesive Research for the donation of the PSA samples

Current Status and Future Perspective on Lithium Metal Anode Production Methods

Lithium metal batteries (LMBs) are one of the most promising energy storage technologies that would overcome the limitations of current Li-ion batteries, based on their low density (0.534 g cm−3), low reduction potential (−3.04 V vs Standard Hydrogen Electrode) as well as their high theoretical capacities (3860 mAh g−1 and 2061 mAh cm−3). The overall cell mass and volume would be reduced while both gravimetric and volumetric energy densities would be greatly improved. Their electrochemical performance, however, is hampered by the low efficiency at high current densities and continuous degradation, which are related, among other factors, to the properties of the lithium metal anode (LMA). Hence, the production and processing of LMAs is crucial to obtain the desired properties that would enable LMBs. Here, the conventional method used for the production of LMAs, which is the combination of extraction, electrowinning, extrusion, and rolling processes, is reviewed. Then, the advances in the different alternative methods that can be used to produce and improve the properties of LMAs are described, which are divided into vapor phase, liquid phase, and electrodeposition. Within this last method, the anode-less concept, for which different approaches to the development of advanced current collectors are illustrated, is included.I.R.L. acknowledges the support of the Ministerio de Ciencia, Innovación y Universidades (No. PID2019-107468RB-C21) and Gobierno Vasco/Eusko Jaurlaritza (No. IT1546-22). This project has received funding from the Basque Government within the ELKARTEK 2021 call (project CICe2021) under the application number KK-2021/00064

Quantum dot/cyclodextrin supramolecular systems based on efficient molecular recognition and their use for sensing

A supramolecular system based on ketoprofen functionalised CdSe/ZnS nanoparticles and pyrene-modified β-CD was prepared and successfully used for molecular sensing of different analytes. In addition, a strategy for the individual recovery of all the components of the sensing assay is reported

Stereodifferentiation in the formation and decay of the encounter complex in bimolecular electron transfer with photoactivated acceptors

Experimental evidence has been obtained for the involvement of encounter complexes between both enantiomers of a π,π* triplet excited ketone and a chiral phenol or indole. Determination of the pre-equilibrium constants (KEC) and the intrinsic decay rate constants (kd) indicates a significant stereodifferentiation in both steps of the quenching process.Perez Prieto, Julia, [email protected] ; Galian, Raquel Eugenia, [email protected] ; Morant Miñana, Maria Carmen, [email protected]

Triplet exciplexes as energy transfer photosensitisers

Experimental evidence is provided for the occurrence of triplet–triplet energy transfer from benzoylthiophene–indole exciplexes to naphthalenes with a remarkable stereodifferentiation; chiral recognition is also observed in the decay of the generated naphthalene triplets.Perez Prieto, Julia, [email protected] ; Galian, Raquel Eugenia, [email protected] ; Morant Miñana, Maria Carmen, [email protected]

¿Puedo diagnosticar la hipoglucemia en hurones domésticos (Mustela putorius furo) con el uso de glucómetros portátiles?

Aims. The diagnosis of hypoglycemia in ferrets (Mustela putorius furo) is based on the detection of a blood  glucose level below 60-70 mg / dl. A blood glucose concentration below these levels is very suggestive of  pancreatic beta cell tumor (insulinoma), which comprises of approximately 25% of all neoplasms diagnosed  in this species. This study aims to check if the low blood glucose values obtained through the use of portable  glucometers are reliable as a method of diagnosing hypoglycemia in this species. Material and methods. In this study, 31 samples of ferrets blood of different ages and sexes are analyzed,  using three types of portable glucometers, comparing these results with the measurements obtained by a  liquid biochemistry analyzer using the glucose oxidase method, considered as one of the standard  measurement methods. Results. One of the three glucometers used in this study underestimates blood glucose values in this species, while another overestimates them, which is a systematic error (predictable) of the equipment that could be  solved by calibrating them for this species. The other glucometer is more consistent with the reference  values, but has a high random error (unpredictable), that is more difficult to correct. Therefore none of the  three teams would be adequate to make a reliable diagnosis of hypoglycemia in ferrets. Conclusions. These results indicate that blood glucose concentrations in ferrets should be confirmed with a  validated laboratory analyzer to reliably diagnose hypoglycemia, and blood glucose meters used only to monitor the disease.  Objetivo. El diagnóstico de la hipoglucemia en hurones (Mustela putorius furo) se basa en la detección de un nivel de glucosa en la sangre inferior a 60- 70 mg / dl. Una concentración de glucosa en sangre por debajo de estos niveles es muy sugestiva de tumor de células beta pancreáticas (insulinoma), que comprende  aproximadamente el 25% de todas las neoplasias diagnosticadas en esta especie. En este estudio se  pretende comprobar si los bajos valores de glucosa en sangre obtenidos mediante el uso de glucómetros  portátiles son fiables como método de diagnóstico de hipoglucemia en esta especie. Material y métodos. En este estudio se analizan 31 muestras de sangre de hurones de distinta edad y sexo,  mediante el uso de tres tipos de glucómetros portátiles, comparando dichos resultados con las medidas  obtenidas mediante un analizador de bioquímica líquida que usa el método de la glucosa oxidasa,  considerado como uno de los métodos estándar de medida. Resultados. Uno de los tres glucómetros utilizado en este estudio subestima los valores de glucosa en sangre en esta especie, mientras que otro los sobreestima, lo que supone un error sistemático (predecible)  de los equipos que se podría solucionar calibrándolos para esta especie. El otro glucómetro que presenta  mayor concordancia con los valores de referencia presenta un error aleatorio elevado (impredecible) más  difícil de corregir. Por tanto ninguno de los tres equipos sería adecuado para realizar un diagnóstico fiable de hipoglucemia en hurones. Conclusiones. Estos resultados indican que las concentraciones de glucosa en sangre en hurones deben confirmarse con un analizador de laboratorio validado para realizar el diagnóstico de hipoglucemia de forma  fiable, y los glucómetros usarse sólo para hacer un seguimiento de la enfermedad.