Reusable Colorimetric Biosensors on Sustainable Silk-Based Platforms.

In biosensor development, silk fibroin is advantageous for providing transparent, flexible, chemically/mechanically stable, biocompatible, and sustainable substrates, where the biorecognition element remains functional for long time periods. These properties are employed here in the production of point-of-care biosensors for resource-limited regions, which are able to display glucose levels without the need for external instrumentation. These biosensors are produced by photopatterning silk films doped with the enzymes glucose oxidase and peroxidase and photoelectrochromic molecules from the dithienylethene family acting as colorimetric mediators of the enzymatic reaction. The photopatterning results from the photoisomerization of dithienylethene molecules in the silk film from its initial uncolored opened form to its pink closed one. The photoisomerization is dose-dependent, and colored patterns with increasing color intensities are obtained by increasing either the irradiation time or the light intensity. In the presence of glucose, the enzymatic cascade reaction is activated, and peroxidase selectively returns closed dithienylethene molecules to their initial uncolored state. Color disappearance in the silk film is proportional to glucose concentration and used to distinguish between hypoglycemic (below 4 mM), normoglycemic (4-6 mM), and hyperglycemic levels (above 6 mM) by visual inspection. After the measurement, the biosensor can be regenerated by irradiation with UV light, enabling up to five measurement cycles. The coupling of peroxidase activity to other oxidoreductases opens the possibility to produce long-life reusable smart biosensors for other analytes such as lactate, cholesterol, or ethanol.

Electrochromogenic Detection of Live Bacteria Using Soluble and Insoluble Prussian Blue.

Microbial detection is crucial for the control and prevention of infectious diseases, being one of the leading causes of mortality worldwide. Among the techniques developed for bacterial detection, those based on metabolic indicators are progressively gaining interest due to their simplicity, adaptability, and, most importantly, their capacity to differentiate between live and dead bacteria. Prussian blue (PB) may act as a metabolic indicator, being reduced by bacterial metabolism, producing a visible color change from blue to colorless. This molecule can be present in two main forms, namely, the soluble and the insoluble, having different properties and structures. In the current work, the bacterial-sensing capacity of soluble and insoluble PB will be tested and compared both in suspensions as PB-NPs and after deposition on transparent indium tin oxide-poly(ethylene terephthalate) (ITO-PET) electrodes. In the presence of live bacteria, PB-NPs are metabolized and completely reduced to the Prussian white state in less than 10 h for soluble and insoluble forms. However, when electrodeposited on ITO-PET substrates, less than 1 h of incubation with bacteria is required for both forms, although the soluble one presents faster metabolic reduction kinetics. This study paves the way to the use of Prussian blue as a metabolic indicator for the early detection of bacterial infection in fields like microbial diagnostics, surface sterilization, food and beverage contamination, and environmental pollution, among others.

Solid Multiresponsive Materials Based on Nitrospiropyran-Doped Ionogels.

The application of molecular switches for the fabrication of multistimuli-responsive chromic materials and devices still remains a challenge because of the restrictions imposed by the supporting solid matrices where these compounds must be incorporated: they often critically affect the chromic response as well as limit the type and nature of external stimuli that can be applied. In this work, we propose the use of ionogels to overcome these constraints, as they provide a soft, fluidic, transparent, thermally stable, and ionic-conductive environment where molecular switches preserve their solution-like properties and can be exposed to a number of different stimuli. By exploiting this strategy, we herein pioneer the preparation of nitrospiropyran-based materials using a single solid platform that exhibit optimal photo-, halo-, thermo-, and electrochromic switching behaviors.

Reversibly Switchable Fluorescent Molecular Systems Based on Metallacarborane-Perylenediimide Conjugates.

Icosahedral metallacarboranes are θ-shaped anionic molecules in which two icosahedra share one vertex that is a metal center. The most remarkable of these compounds is the anionic cobalt-based metallacarborane [Co(C2 B9 H11 )2 ]- , whose oxidation-reduction processes occur via an outer sphere electron process. This, along with its low density negative charge, makes [Co(C2 B9 H11 )2 ]- very appealing to participate in electron-transfer processes. In this work, [Co(C2 B9 H11 )2 ]- is tethered to a perylenediimide dye to produce the first examples of switchable luminescent molecules and materials based on metallacarboranes. In particular, the electronic communication of [Co(C2 B9 H11 )2 ]- with the appended chromophore unit in these compounds can be regulated upon application of redox stimuli, which allows the reversible modulation of the emitted fluorescence. As such, they behave as electrochemically-controlled fluorescent molecular switches in solution, which surpass the performance of previous systems based on conjugates of perylendiimides with ferrocene. Remarkably, they can form gels by treatment with appropriate mixtures of organic solvents, which result from the self-assembly of the cobaltabisdicarbollide-perylendiimide conjugates into 1D nanostructures. The interplay between dye π-stacking and metallacarborane electronic and steric interactions ultimately governs the supramolecular arrangement in these materials, which for one of the compounds prepared allows preserving the luminescent behavior in the gel state.

Switchless Multiplexing of Graphene Active Sensor Arrays for Brain Mapping.

Sensor arrays used to detect electrophysiological signals from the brain are paramount in neuroscience. However, the number of sensors that can be interfaced with macroscopic data acquisition systems currently limits their bandwidth. This bottleneck originates in the fact that, typically, sensors are addressed individually, requiring a connection for each of them. Herein, we present the concept of frequency-division multiplexing (FDM) of neural signals by graphene sensors. We demonstrate the high performance of graphene transistors as mixers to perform amplitude modulation (AM) of neural signals in situ, which is used to transmit multiple signals through a shared metal line. This technology eliminates the need for switches, remarkably simplifying the technical complexity of state-of-the-art multiplexed neural probes. Besides, the scalability of FDM graphene neural probes has been thoroughly evaluated and their sensitivity demonstrated in vivo. Using this technology, we envision a new generation of high-count conformal neural probes for high bandwidth brain machine interfaces.

Photoelectro-Enzymatic Glucose Reusable Biosensor by Using Dithienylethene Mediators.

In the development of colorimetric biosensors, the use of electrochromic mediators has been accepted and widely used during decades. The main drawback of these types of enzymatic substrates is the difficult recovery of the initial redox state of the molecule, which can be done electrochemically or by antioxidants addition, complicating the initially simple structure of the biosensor. those strategies are rarely followed Actually, being the disposable biosensor configuration the most extended for this detection mechanisms. Alternatively, we propose the first reported use of a diacid dithienylethene 1,2-bis(5-carboxy-2-methylthien-3-yl)cyclopentene (DTE) photoelectrochromic compound as a substrate of the horseradish peroxidase (HRP). The photoisomerization between the open (DTEo) and closed (DTEc) forms of the molecule and the respective shift in the redox potential allowed the light-induced enzymatic detection of glucose in the glucose oxidase [(GOx)]-HRP cascade system. This fast and easy control over the enzymatic substrate availability by light pulses permits a gradually consumption and the light-regeneration of the biosensor for a number of cycles. We consider the presented results transcendent in the development of reusable and light-controlled photonic biosensing systems.

Sustainable and efficient electrosynthesis of naproxen using carbon dioxide and ionic liquids.

The use of CO2 as a C1 carbon source for synthesis is raising increasing attention both as a strategy to bring value to carbon dioxide capture technologies and a sustainable approach towards chemicals and energy. The presented results focus on the application of electrochemical methods to incorporate CO2 into organic compounds using ionic liquids as electrolytes, which provides a green alternative to the formation of C-C bonds. In this sense, the current manuscript shows that Naproxen (6-Methoxy-α-methyl-2-naphthaleneacetic acid) can be synthetizing in high yield (89%) and conversion rates (90%) through an electrocarboxylation process using CO2 and ionic liquids. The role of the cathode and solvent, which can potentially enhance the synthesis, is also discussed. The "green" route described in the current work would open a new sustainable strategy for the electrochemical production of pharmaceutical compounds.

Electrochromic Self-Electrostabilized Polypyrrole Films Doped with Surfactant and Azo Dye.

Two azo dyes, acid red 1 (AR1) and acid red 18 (AR18), were used alone or in combination with sodium dodecyl sulfate (SDS) for the electropolymerization of a pyrrole monomer. Polypyrrole (PPy) showed higher redox capacity when SDS and AR18 were used simultaneously as dopant agents (PPy/AR18-SDS) than when the conducting polymer was produced in the presence of SDS, AR18, AR1, or an AR1/SDS mixture. Moreover, PPy/AR18-SDS is a self-stabilizing material that exhibits increasing electrochemical activity with the number of oxidation-reduction cycles. A mechanism supported by scanning electron microscopy and X-ray diffraction structural observations was proposed to explain the synergy between the SDS surfactant and the AR18 dye. On the other hand, the Bordeaux red color of PPy/AR18-SDS, which exhibits an optical band gap of 1.9 eV, rapidly changed to orange-yellow and blue colors when films were reduced and oxidized, respectively, by applying linear or step potential ramps. Overall, the results indicate that the synergistic utilization of AR18 and SDS as dopant agents in the same polymerization reaction is a very successful and advantageous strategy for the preparation of PPy films with cutting-edge electrochemical and electrochromic properties.

Experiencia de los cudadores de crianza ante el acogimiento familiar del niño maltratado / Experience of the foster carers in the family care of the battered child / Experiência dos cuidadores adotivos no cuidado familiar da criança espancada

La presente te4sis versó acerca del sistema de protección del niño maltratado conocido como acogimiento infantil. Esta investigación se realizó en dos familias que tienen en protección a un menor lactante. El objetivo fue describir las experiencias de los cuidadores de crianza ante el acogimiento familiar del niño maltratado. La metodología empleada fue cualitativa fenomenológica descriptiva; las técnicas para obtención dela información fueron entrevistas semi-estructuradas, de profundidad, observación participante y notas de campo. El medio para recolectar la información fue con audio-grabadora digital. El procedimiento para procesar, clasificar y analizar la información se desarrolló como lo proponen Miles y Huberman. Los resultados hallados con el análisis estructural del conjunto de datos obtenidos se organizaron en forma de unidades temáticas llamadas categorías y sub-categorías, de esta forma me permitió evidenciar que entre los hallazgos de las experiencias que tienen los cuidadores al acoger familiarmente a un menor maltratado lo aceptan ante la extrema urgencia y que las experiencias de cuidado de crianza ante el acogimiento, las familias acogedoras conllevan un proceso temporal, así mismo estas narraciones van r4espondiendo a la pregunta de investigación. Conclusiones: Los resultados de la investigación señalan que las familias implicadas requieren apoyos de distintas clases, por lo tanto el trabajo para la disciplina de enfermería es muy casto para desarrollar acciones y estrategias de salud que mejoren las condiciones tanto de los cuidadores como para el cuidado de crianza que otorgan; la implementación de Programas Educativos que atiendan la orientación, formación, consejería, acompañamiento y seguimiento de las familias que acogen a un menor. Por su parte, los organismos que delegan la tutela en la acogida del menor como son la Institución de salud y autoridades jurídicas implicadas, requiere de sus participaciones en gran medida de distinta índole, así mismo en la implementación de políticas públicas de salud con miras a mejorar las condiciones de la población aquí implicada.

This te4sis dealt with the system of protection of abused children known as foster care. This research was conducted in two families that have a child under protection. The objective was to describe the experiences of the foster caregivers before the family care of the abused child. The methodology used was descriptive phenomenological qualitative; the techniques for obtaining information were semi-structured interviews, depth, participant observation and field notes. The means to collect the information was with digital audio-recorder. The procedure to process, classify and analyze the information was developed as proposed by Miles and Huberman. The results found with the structural analysis of the set of data obtained were organized in the form of thematic units called categories and sub-categories, in this way it allowed me to show that among the findings of the experiences that caregivers have when welcoming a mistreated child. they accept it in the face of extreme urgency and that the experiences of foster care in the care, welcoming families involve a temporary process, likewise these narrations are rspondiendo to the research question. Conclusions: The results of the research indicate that the families involved require support from different classes, therefore the work for the nursing discipline is very chaste to develop actions and health strategies that improve the conditions of both caregivers and care of parenting that they grant; the implementation of Educational Programs that address the orientation, training, counseling, accompaniment and monitoring of families that host a child. On the other hand, the organizations that delegate guardianship in the reception of the minor, such as the health institution and legal authorities involved, require their participation to a large extent of a different nature, as well as in the implementation of public health policies with a view to improve the conditions of the population involved here.

Essa teia tratou do sistema de proteção de crianças vítimas de abuso conhecido como assistência social. Esta pesquisa foi realizada em duas famílias que têm uma criança sob proteção. O objetivo foi descrever as experiências dos cuidadores adotivos diante do cuidado familiar da criança abusada. A metodologia utilizada foi descritiva fenomenológica qualitativa; as técnicas para obtenção de informações foram entrevistas semiestruturadas, profundidade, observação participante e notas de campo. Os meios para coletar as informações eram com gravador de áudio digital. O procedimento para processar, classificar e analisar as informações foi desenvolvido conforme proposto por Miles e Huberman. Os resultados encontrados com a análise estrutural do conjunto de dados organizados como unidades temáticas chamados categorias e sub-categorias, assim me permitiu mostrar que, entre as conclusões das experiências com cuidadores para familiarmente acomodar menos agredidas eles aceitam o rosto de extrema urgência e que as experiências de assistência social para promover o cuidado, famílias de acolhimento levar um processo temporal, também estas histórias são r4espondiendo à questão da pesquisa. Conclusões: Os resultados da pesquisa indicam que as famílias envolvidas requerem suporte de vários tipos, portanto, trabalhar para a disciplina de enfermagem é muito casto para desenvolver ações e estratégias de saúde que irão melhorar as condições de ambos os cuidadores e cuidados de parentalidade que eles concedem; a implementação de programas educacionais que atendam a orientação, treinamento, aconselhamento, apoio e acompanhamento das famílias que hospedam um menor. Por sua parte, as agências de delegar a custódia em acolher a criança como são a instituição de saúde e as autoridades legais envolvidos, requer suas participações natureza muito diferente, também na implementação de políticas públicas de saúde, com vista a melhorar as condições da população envolvida aqui.