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© 2014, Springer Science+Business Media Dordrecht. Structural properties of bacterial cellulose (BC) depend on the microstructure of the material, which in turn is influenced by the bacterial strain. This paper reports the production of BC thin films from two bacterial strains, gluconacetobacter xylinus (GX) and gluconacetobacter europaeus (GE), and three methods of drying the films; at room temperature, freeze drying and supercritical drying. The porosity, transparency, water absorption capacity (WAC) and mechanical properties of the obtained films are further investigated. We conclude that materials with different properties can be fabricated by selecting the bacterial strain or the drying method. Supercritical drying of films of GE achieved mechanically robust and extremely light films, 0.05 g/mL, with up to 96 % of porosity, and with a WAC up 110 times their dried weight. We determined that materials resulting from GE strain are not much affected by the drying method. On the other hand, GX produced BC films more sensitive to the drying method used. Films are denser, 0.6–0.2 g/mL, with tunable porosity from 60 to 90 % and their maximum WAC is 66 times their dried weight. ; The research leading to these results has received funding from the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program (FP7/2007-2013) under REA grant agreement no 303630 and cofounded by the European Social Fund. Authors acknowledge the funding from Spanish Ministry of Economy MAT 2012-35324, from the Generalitat de Catalunya 2014SGR213, COST Action MP1202, Ramon y Cajal grant RYC-2010-06082 (AL), and Chinese Scholarship Council fellowship (MZ). The group of Dr. Alex Peralvarez for their help in the bacterial culture, Dr. Josep PuigMartı´ and the group of Prof. David Amabilino for the use of the optical microscope, Prof. Elies Molins and Toni Pons for the use and training in the use of the freeze drier and Dr. Roberto L. Guzman de Villoria for his advices in the mechanical measurements. ; Peer Reviewed

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely used for biological applications due to their unique properties compared to their bulk counterparts, simplified SPIONs stabilization protocols applicable for a wide spectra of biological media remains a challenging issue. In this work, SPIONs with different surface coatings, tetramethylammonium hydroxide-coated SPIONs (T-SPIONs), and citrate-coated SPIONs (C-SPIONs) were synthesized by a facile, rapid and cost effective microwave-assisted method. C-SPIONs show robust stability in biological media of phosphate buffered saline and Roswell Park Memorial Institute Medium, while destabilize in DMEM. T-SPIONs were found to aggregate rapidly and significantly in all tested media. Then, a modified pH adjusted-BSA adsorption protocol and an addition of excess trisodium citrate dihydrate (Na3Cit) were used to enhance their stability in the media. The BSA adsorption protocol showed great efficiency in stabilizing the dispersed state of both SPIONs in the tested media, while the addition of excess Na3Cit showed limited effect, and it was only applicable for C-SPIONs. The formed BSA layer on SPIONs could be imaged by negative staining TEM, and revealed by Cryo-TEM, FTIR, DLS, and the zeta potential measurements. Results indicated that BSA forms a monolayer of a thickness of about 3 ± 1 nm and BSA interacts with C-SPIONs and T-SPIONs through their coating, rather than by replacing them. This synthetic method and stabilization protocol offer a general methodology to obtain SPIONs with a variety of surfactants, stable in different biological media in few minutes. © 2014 Springer Science+Business Media. ; Acknowledgments The research leading to these results has received funding from the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program (FP7/2007-2013) under REA grant agreement n8 303630 and cofounded by the European Social Fund. Authors acknowledge the funding from Spanish Ministry of Economy MAT 2012-35324, COST Action MP1202 and Ramon y Cajal grant RYC-2010-06082 (AL), China Scholarship Council fellowship (SMY, 201206150053). ; Peer Reviewed

Nanomaterials give rise to unique biological reactivity that needs to be thoroughly investigated. The quest for enhanced magnetic nanomaterials of different shapes, magnetic properties, or surface coatings continues for applications in drug delivery, targeting therapies, biosensing, and magnetic separation. In this context, the use of simple in vivo models, such as Caenorhabditis elegans, to biologically evaluate nanoparticles is currently in increasing demand as it offers low-cost and information-rich experiments. In this work, we evaluated how surface modification (citrate- and protein-coated) of superparamagnetic iron oxide nanoparticles (C-SPIONs and BSA-SPIONs, respectively) induces changes in their toxicological profile and biodistribution using the animal model C. elegans and combining techniques from materials science and biochemistry. The acute toxicity and nanoparticle distribution were assessed in two populations of worms (adults and larvae) treated with both types of SPIONs. After 24 h treatment, nanoparticles were localized in the alimentary system of C. elegans; acute toxicity was stronger in adults and larvae exposed to C-SPIONs rather than BSA-SPIONs. Adult uptake was similar for both SPION types, whereas uptake in larvae was dependent on the surface coating, being higher for BSA-SPIONs. Nanoparticle size was evaluated upon excretion, and a slight size decrease was found. Interestingly, all results indicate the protective effects of the BSA to prevent degradation of the nanoparticles and decrease acute toxicity to the worms, especially at high concentrations. We argue that this relevant information on the chemistry and toxicity of SPIONs in vivo could not be gathered using more classical in vitro approaches such as cell culture assays, thus endorsing the potential of C. elegans to assess nanomaterials at early stages of their synthetic formulations. ; C. elegans N2 and E. coli OP50 were provided by the CGC, which is funded by NIH Office of Research Infrastructure Programs (P40 OD010440). The research leading to these results has received funding from the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program (FP7/2007-2013) under REA grant agreement nº 303630 and cofounded by the European Social Fund. Authors acknowledge the funding from Spanish Ministry of Economy MAT 2012-35324 and FEDER funds, the Generalitat de Catalunya 2014SGR213, the COST Action MP1202, Ramon y Cajal grant RYC-2010-06082 (AL), China Scholarship Council fellowship (SMY, 201206150053), and FPU fellowship FPU12/05549 (LGM). ; Peer Reviewed

Porous carbons are important cathode materials for metal-air batteries, but the most usual methods to prepare these porous structures are complex and of high cost. We have prepared porous carbons from bacterial cellulose (BC) hydrogels by a simple water-alcohol solvent exchange before carbonization. Alcohol treatment facilitates looser and more open structures than untreated BC, resulting in porous carbon structures with high surface area, appropriate for electrochemical applications. Used as cathodes in lithium-oxygen batteries, the carbon derived from 1-butanol treated BC has excellent discharge capacity (5.6 mA h cm−2) and good cycle life. This work presents a sustainable, straightforward and fast way to prepare porous carbon materials from BC. ; This research was supported by the Spanish Government, through the "Severo Ochoa" Programme for Centers of Excellence in R&D (CEX2019-000917-S), the projects MAT2017-91404-EXP and RTI2018-096273-B-I00 and the PhD scholarships of S. R. (BES-2016-077533) with FEDER co-funding. W.W. gratefully acknowledges the support from the China Scholarship Council (CSC No.:201808340076). The authors participate in the SusPlast and FLOWBAT 2021 platforms promoted by the Spanish National Research Council (CSIC) and in the Aerogels COST ACTION (CA 18125). They also acknowledge the Generalitat de Catalunya (2017SGR765 and 2017SGR1687 grants). This work has been performed within the framework of the doctoral program in materials science of UAB (W. W. and S.R–S.) ; Peer reviewed

Actuated structures are becoming relevant in medical fields; however, they call for flexible/soft-base materials that comply with biological tissues and can be synthesized in simple fabrication steps. In this work, we extend the palette of techniques to afford soft, actuable spherical structures taking advantage of the biosynthesis process of bacterial cellulose. Bacterial cellulose spheres (BCS) with localized magnetic nanoparticles (NPs) have been biosynthesized using two different one-pot processes: in agitation and on hydrophobic surface-supported static culture, achieving core-shell or hollow spheres, respectively. Magnetic actuability is conferred by superparamagnetic iron oxide NPs (SPIONs), and their location within the structure was finely tuned with high precision. The size, structure, flexibility and magnetic response of the spheres have been characterized. In addition, the versatility of the methodology allows us to produce actuated spherical structures adding other NPs (Au and Pt) in specific locations, creating Janus structures. The combination of Pt NPs and SPIONs provides moving composite structures driven both by a magnetic field and a H2O2 oxidation reaction. Janus Pt/SPIONs increased by five times the directionality and movement of these structures in comparison to the controls. ; Authors acknowledge financial support from the Spanish Ministry of Science and Innovation through the RTI2018-096273-B-I00 project, the "Severo Ochoa" Programme for the Centres of Excellence in R&D (CEX2019-000917-S), and the PhD scholarship of S.R.-S (BES-2016-077533). The Generalitat de Catalunya project 2017SGR765 is also acknowledged. The authors also express their gratitude to the technical services of ICMAB-CSIC (electron microscopy, magnetometry and Nanoquim facilities) and CRAG (microscopy facilities). The authors participate in the CSIC Interdisciplinary Platform for Sustainable Plastics toward a Circular Economy, SUSPLAST, the EPNOE Association, Ministerio de Ciencia e Innovación, Acciones de dinamización Redes de Investigación RED2018-102469-T and in the Aerogels COST ACTION (CA 18125). ; With funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000917-S). ; Peer reviewed

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. ; We report a novel hybrid T1/T2 dual MRI contrast agent by the encapsulation of SPIONs (T2 contrast agent) into an iron-based coordination polymer with T1-weighted signal. This new hybrid material presents improved relaxometry and low cytotoxicity, which make it suitable for its use as contrast agent for MRI. ; This work was supported by project MAT2012-38318-C03-02 and MAT2012-35324 and BIO2013-44973-R from the Spanish Government and FEDER funds. F.N. thanks the Ministerio de Ciencia e Innovación (MICINN) for a postdoctoral JdC fellowship and A.L. thanks Ramon y Cajal grant RYC-2010-06082. SM.Y. acknowledges the China Scholarship Council fellowship (201206150053). Authors also thank MP1202 and TD1004 Cost Actions. ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295). MR studies were carried out at the joint NMR facility of UAB and CIBER-BBN, Unit 25 of NANBIOSIS, with a 7T horizontal. ; We acknowledge the support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). ; Peer reviewed

Industries, governments and consumers increasingly request sustainable resources and greener routes for the integration of advanced functional nanocomposites in products and devices. Among renewable biopolymers, cellulose deserves special consideration since it is the most abundant one. While inorganic nanoparticles add functional properties to a nanocomposite, a flexible and porous cellulosic support will facilitate the interaction of the nanoparticles with the surroundings, their handling and recycling. A significant challenge is to develop high strength, flexible nanobiocomposites controlling the nanoparticle properties, their volume fraction and their topographic distribution within the scaffold. A new concept is presented here for multifunctional laminates where layers consist of bacterial cellulose fibrils decorated by inorganic nanoparticles. Each layer can provide a specific function using a different nanoparticle. As model systems, we have selected two metals (Au, Ag) and two semiconductors (TiO2 and Fe2O3). Energy-efficient microwave-assisted synthetic routes have been used to in situ nucleate and grow the inorganic nanocrystals on the cellulose fibrils. Then, functionalized bacterial cellulose films can be arranged as laminates in a millefeuille construct simply by layering and drying the wet films at 60 °C. After drying, they perform as a single integrated and thicker film. Structural, functional and mechanical integrity of the laminates have been investigated. Molecular dynamics simulations were used to compute the surface adhesion energy between two cellulose fibrils and the results are discussed in light of the experimental peel-off data for the separation of the layers in the laminate. ; Peer reviewed

19 páginas.- 9 figuras.- referencias ; Tomato varieties resistant to the bacterial wilt pathogen Ralstonia solanacearum have the ability to restrict bacterial movement in the plant. Inducible vascular cell wall reinforcements seem to play a key role in confining R. solanacearum into the xylem vasculature of resistant tomato. However, the type of compounds involved in such vascular physico-chemical barriers remain understudied, while being a key component of resistance. Here we use a combination of histological and live-imaging techniques, together with spectroscopy and gene expression analysis to understand the nature of R. solanacearum-induced formation of vascular coatings in resistant tomato. We describe that resistant tomato specifically responds to infection by assembling a vascular structural barrier formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties, effectively contributing to resistance. ; Research is funded by MCIN/AEI/10.13039/501100011033 (NSC, MV), MCIN/AEI/PID2019-110330GB-C21 (MF, OS), MCIN/AEI/PID2020-118968RBI00 (JR), through the 'Severo Ochoa Programme for Centres of Excellence in R&D' (SEV-2015-0533, CEX2019-000917 and CEX2019-000902-S funded by MCIN/AEI/ 10.13039/501100011033), and by the Spanish National Research Council (CISC) pie-201620E081 (JR, AG) and the Generalitat de Catalunya (2017SGR765 grant). AK is the recipient of a Netaji Subhas – Indian Council of Agricultural Research International Fellowship. SS acknowledges financial support from DOC-FAM, European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 754397. This work was also supported by the CERCA Program/Generalitat de Catalunya. ; Peer reviewed

The aim of our study was to assess if the sodium salt of cobaltabis(dicarbollide) and its di-iodinated derivative (Na[o-COSAN] and Na[8,8'-I2-o-COSAN]) could be promising agents for dual anti-cancer treatment (chemotherapy + BNCT) for GBM. ; This work was supported by the Spanish Ministerio de Economía y Competitividad (PID2019-106832RB-I00, RTI2018-096273-B-I00), the Generalitat de Catalunya (2017SGR1720, 2017SGR765) and the 'Severo Ochoa' Program for Centers of Excellence in R&D (SEV-2015-0496), S. Geninatti Crich received funding from AIRC (Associazione Italiana per la Ricerca sul Cancro) under IG 2019—ID. 23267 project and by Fundação para a Ciência e Tecnologia (FCT) Portugal for projects UID/MULTI/04349/2019 and PTDC/BTM-TEC/29256/2017 and for the PhD scholarship DFA/BD/ 07119/2020 to C.I.G. Pinto. A.L. and A.M.-J. participate in the networks of EPNOE, Red Nanocare RED2018-102469-T, and CSIC Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy, SUSPLAST). Jewel A.M. Xavier acknowledges the DOC-FAM program under the Marie Sklodowska-Curie grant agreement nº 754397. Miquel Nuez-Martinez, Jewel A.M. Xavier, and Amanda Muñoz-Juan (Ph.D. scholarship FPU18/05190) are enrolled in the Ph.D. program of the UAB. ; With funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000917-S). ; Peer reviewed