On the Interaction between 1D Materials and Living Cells

One-dimensional (1D) materials allow for cutting-edge applications in biology, such as single-cell bioelectronics investigations, stimulation of the cellular membrane or the cytosol, cellular capture, tissue regeneration, antibacterial action, traction force investigation, and cellular lysis among others. The extraordinary development of this research field in the last ten years has been promoted by the possibility to engineer new classes of biointerfaces that integrate 1D materials as tools to trigger reconfigurable stimuli/probes at the sub-cellular resolution, mimicking the in vivo protein fibres organization of the extracellular matrix. After a brief overview of the theoretical models relevant for a quantitative description of the 1D material/cell interface, this work offers an unprecedented review of 1D nano- and microscale materials (inorganic, organic, biomolecular) explored so far in this vibrant research field, highlighting their emerging biological applications. The correlation between each 1D material chemistry and the resulting biological response is investigated, allowing to emphasize the advantages and the issues that each class presents. Finally, current challenges and future perspectives are discussed

Improved Photocatalytic Activity of Polysiloxane TiO2 Composites by Thermally Induced Nanoparticle Bulk Clustering and Dye Adsorption

Fine control of nanoparticle clustering within polymeric matrices can be tuned to enhance the physicochemical properties of the resulting composites, which are governed by the interplay of nanoparticle surface segregation and bulk clustering. To this aim, out-of-equilibrium strategies can be leveraged to program the multiscale organization of such systems. Here, we present experimental results indicating that bulk assembly of highly photoactive clusters of titanium dioxide nanoparticles within an in situ synthesized polysiloxane matrix can be thermally tuned. Remarkably, the controlled nanoparticle clustering results in improved degradation photocatalytic performances of the material under 1 sun toward methylene blue. The resulting coatings, in particular the 35 wt % TiO2-loaded composites, show a photocatalytic degradation of about 80%, which was comparable to the equivalent amount of bare TiO2 and two-fold higher with respect to the corresponding composites not subjected to thermal treatment. These findings highlight the role of thermally induced bulk clustering in enhancing photoactive nanoparticle/polymer composite properties

Push-Pull copolymers in thin film for electronic application

In this work, push-pull copolymers have been synthesized by electrochemical and chemical methods in order to fabricate new devices on flexible substrates, for electronic applications in several areas as electrochromism, solar cells and sensors. Electrochemical synthesis was employed to synthesize copolymers composed of acceptor (A) N,N -bis(2-octyldodecyl)-2,6-bis(5-(thioph-2-yl)thiophen-2-yl)naphthalene-1,4,5,8-bis(dicarboximide) (s-NDI2ODT4) and donor (D) ethylenedioxythiophene (EDOT) units on (indium tin oxide/polyethylene terephtalate) ITO/PET substrates, allowing for the fabrication of electrochromic devices, featuring an optical contrast of 29%. In the same way, it was possible to fabricate novel electrochromic devices by combining NDI2ODT4 with the novel system bis-thiophene fulleropyrrolidine (bis-Th2P-C60). Moreover, it was also possible to demonstrate that P(NDI2ODT4), P(bis-Th2P-C60), co(NDI2ODT4-bis-Th2P-C60) are good electron acceptor in planar heterojunction(PHJ)-based Organic Solar Cells (OSCs) with poly(3-hexylthiophene-2,5-diyl) (P3HT). Electrochromic devices and OSCs based on bis-Th2P-C60 combined with P(NDI2ODT4), do not show good results. This can be explained by the fact that bis-Th2P-C60 imposes a distortion of the main polymeric chain. In addition, the combination of fulleropyrrolidine (A) and thiophene (D) moieties in copolymers has shown to improve the morphology in thin film bulk heterojunctions (BHJs). In particular, the small percentages of a novel tetra-thiophene fulleropyrrolidine (Th4P-C60) copolymer acted as segregation modulators in BHJs based on P3HT mixed with Phenyl-C61-butyric acid methyl ester (PCBM) allowing to improve the state-of-the-art power conversion efficiency of plastic P3HT/PCBM OSCs up to 4.46 %. Finally, preliminary results are shown on the application of Th4P-C60 based systems electrochemically co-deposited with hemin molecules for the recognition of H2O2 in plastic electrochemical sensors. This gives interesting perspectives for the application of properly designed D-A copolymers and/or co-deposited systems for the recognition of those drugs developing H2O2 during their metabolism

Improved performance in flexible organic solar cells by using copolymeric phase-separation modulators

One of the main problems related to the low performance of the organic solar cells (OSCs), concerns the low mobility of the materials constituting the heterojunction. Indeed, the poor charge transport in the active layer is the principal cause of a competition between separation and recombination of the photogenerated carriers. In this regard, a major obstacle to enhance OSCs efficiency is developing strategies to optimize the exciton dissociation and, consequently, the charge collection at the electrodes. Donor and acceptor systems must be well mixed on the length scale of 5 – 20 nm (exciton diffusion length) to meet the criteria for efficient exciton dissociation. In addition, the network structure should involve continuous donor-acceptor pathways for efficient carrier transport. The most common practice to achieve this goal is by thermal or solvent annealing of active layer.[1] However, this approach often leads to an unwanted phase segregation with formation of large domains where only a small fraction of excitons could diffuse to the donor-acceptor interface.[2] In this work, we show how this challenge is achievable by incorporating phase-separation modulators into bulk heterojunction (BHJ). In particular, three copolymers based on polythiophene and C60 units have been designed, easily synthesized, characterized, and employed as additive in P3HT:PCBM devices. The effect of the thienyl spacer length between C60 monomers on optoelectronic properties, morphology, and structure of heterojunction has been examined using several techniques (NMR, FTIR, XPS, XRD and AFM). We observed that small quantities of these systems can play a critical role in tuning the device morphology by improving the phase separation in thin film heterojunction.[3] In particular, these copolymers act as phase separation modulators by controlling the growth of donor/acceptor domains in the heterojunction, during the thermal annealing process. Indeed, by employing copolymers containing oligothiophenic chains with size of about 8 nm, a large number of domains with a size comparable to the length scale of exciton diffusion are generated, resulting in the highest power conversion efficiency (PCE) (4.46 %) and short current density (JSC) (16.15 mA cm-2) values reported so far for P3HT:PCBM solar cells on plastic substrates. Moreover, the results obtained in preliminary investigations on the other devices containing different fullerene acceptors seem to show the effectiveness and the generality of our approach. Finally, bending tests showed that OSCs with copolymers maintain higher level of performance than reference devices, thus giving new perspectives to applications of flexible photovoltaics

Low angle bending detection semi-transparent piezoresistive sensor

We designed, fabricated, and validated a piezoresistive bending sensor, a fundamental component of wearable electronic devices for monitoring human motion. The most diffused opaque carbon-based resistance flex sensors suffer from low detection for small bending angles. The sensor we here present is based on a semi-transparent active material (fulleropyrrolidine bisadducts polymer) and has the remarkable advantage of good electrical properties for low bending angles. The fabrication steps are effective since a pre-patterned ITO/PET surface is functionalized by chronoamperometric deposition, and the silver electrical contacts are inkjet printed. We propose a fitting function of the measured thin film resistance curve vs. the bending angle, showing promising properties as a complimentary bending sensor to the most diffused flex sensors. The results pave the way to new applications and more performant wearables

Informe final del proyecto: Isótopos estables y paleoecología del Cuaternario continental de Uruguay

El Cuaternario se ha caracterizado por constantes fluctuaciones climáticas, alternando entre glaciaciones y períodos cálidos (interglaciares). Las unidades cuaternarias continentales de Uruguay consideradas en este proyecto (Formaciones Sopas y Dolores) contienen dentro de su registro fósil moluscos y xenartros (ambos con representantes en la fauna actual),además de una extensa fauna de otros vertebrados, plantas, icnofósiles y microfósiles. El estudio de los ensambles de moluscos fósiles continentales (terrestres y dulceacuícolas) tienen una amplia aplicación como indicadores paleoclimáticos y paleoecológicos, permitiendo realizar reconstrucciones paleoambientales muy precisas. Además, los moluscos dulceacuícolas incorporan carbonato de calcio (CaCO3) en equilibrio con el ambiente, el análisis de isótopos estables en moluscos fósiles permite reconstruir la temperatura al momento de la vida del organismo. Algo similar ocurre con los mamíferos, pero en este caso, es la incorporación de carbonatos a través de la dieta lo que permite reconstruir además de la preferencia alimenticia, el ambiente asociado a los organismos, a partir de la identificación de plantas de tipo C3 (mayoría de plantas) y C4 (aquellas que habitan ambientes preferentemente abiertos). Entonces, el objetivo general de este proyecto es establecer la variación de parámetros climáticos y ecológicos a lo largo del Cuaternario continental de Uruguay a partir de las asociaciones de fósiles, usando para ello sus características ecológicas y el análisis de isótopos estables, comparando de estos últimos, los resultados de moluscos y xenartros entre sí, y asimismo estableciendo una relación de cuál de los dos proxies es más adecuado para la reconstrucción paleoambiental, o si ambos resultados son complementarios, cosa que a la fecha no se ha realizado. Sus conclusiones brindarán datos acerca de cómo puede ser afectada la fauna actual en caso de cambios climáticos futuros.Agencia Nacional de Investigación e Innovació

Informe final del proyecto: Isótopos estables y paleoecología del Cuaternario continental de Uruguay

El Cuaternario se ha caracterizado por constantes fluctuaciones climáticas, alternando entre glaciaciones y períodos cálidos (interglaciares). Las unidades cuaternarias continentales de Uruguay consideradas en este proyecto (Formaciones Sopas y Dolores) contienen dentro de su registro fósil moluscos y xenartros (ambos con representantes en la fauna actual),además de una extensa fauna de otros vertebrados, plantas, icnofósiles y microfósiles. El estudio de los ensambles de moluscos fósiles continentales (terrestres y dulceacuícolas) tienen una amplia aplicación como indicadores paleoclimáticos y paleoecológicos, permitiendo realizar reconstrucciones paleoambientales muy precisas. Además, los moluscos dulceacuícolas incorporan carbonato de calcio (CaCO3) en equilibrio con el ambiente, el análisis de isótopos estables en moluscos fósiles permite reconstruir la temperatura al momento de la vida del organismo. Algo similar ocurre con los mamíferos, pero en este caso, es la incorporación de carbonatos a través de la dieta lo que permite reconstruir además de la preferencia alimenticia, el ambiente asociado a los organismos, a partir de la identificación de plantas de tipo C3 (mayoría de plantas) y C4 (aquellas que habitan ambientes preferentemente abiertos). Entonces, el objetivo general de este proyecto es establecer la variación de parámetros climáticos y ecológicos a lo largo del Cuaternario continental de Uruguay a partir de las asociaciones de fósiles, usando para ello sus características ecológicas y el análisis de isótopos estables, comparando de estos últimos, los resultados de moluscos y xenartros entre sí, y asimismo estableciendo una relación de cuál de los dos proxies es más adecuado para la reconstrucción paleoambiental, o si ambos resultados son complementarios, cosa que a la fecha no se ha realizado. Sus conclusiones brindarán datos acerca de cómo puede ser afectada la fauna actual en caso de cambios climáticos futuros.Agencia Nacional de Investigación e Innovació

Symmetric naphthalenediimidequaterthiophenes for electropolymerized electrochromic thin films

A new symmetric naphthalenediimidequaterthiophene (s-NDI2ODT4) was synthesized and exhibited the capability to electropolymerize alone or with EDOT affording polymers with controlled donor/acceptor monomer ratios. s-NDI2ODT4-EDOT-based copolymers showed low band gaps, wide optical absorption ranges extending to the near IR region, tuned electrical properties, thin-film surface morphology and hydrophilicity as well as high coloration efficiency in electrochromic devices