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Guarrotxena N.,CSIC - Institute of Polymer Science and Technology | Bazan G.C.,University of California at Santa Barbara
Advanced Materials

Simultaneous detection of multiple proteins on a single spot can be efficiently achieved by using multiplexed surface-enhanced Raman spectroscopy (SERS)-encoded nanoparticle 'antitags' consisting of poly(ethylene glycol) (PEG)-protected silver dimers (and higher aggregates) and antibody-tagging entities. The effective SERS-based multivariate deconvolution approach guarantees an accurate and successful distinguishable identification of single and multiple proteins in complex samples. Their potential application in multiplexed SERS bioimaging technology can be easily envisaged. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Diez-Pascual A.M.,CSIC - Institute of Polymer Science and Technology | Diez-Vicente A.L.,Airbus
ACS Applied Materials and Interfaces

Novel poly(ether ether ketone) (PEEK) based nanocomposites have been fabricated via melt-blending by addition of a carboxylated polymer derivative covalently grafted onto the surface of hydroxyl-terminated ZnO nanoparticles. Their morphology, thermal, mechanical, tribological, and antibacterial properties have been analyzed and compared with those of composites reinforced with pristine ZnO. The Fourier transform infrared (FT-IR) spectra corroborate the success of the grafting reaction, showing the appearance of signals related to ester linkages. Microscopic observations demonstrate that the polymer grafting improves the nanoparticle dispersion within the matrix. A progressive rise in thermal stability and flame retardant ability is found with increasing ZnO concentration, with an exceptional increment in the maximum degradation rate temperature of 70 C at 5.0 wt % loading. The crystallization and melting temperature of PEEK decrease upon incorporation of the grafted nanofillers, attributed to the restrictions on polymer chain mobility and crystal growth imposed by the strong ZnO-matrix interactions. Nanocomposites with polymer-grafted nanoparticles exhibit higher stiffness, strength, ductility, toughness and glass transition temperature whilst lower coefficient of friction and wear rate than the neat polymer and composites with bare ZnO. Further, they show superior antibacterial activity against both the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus bacteria. The antimicrobial effect increases upon raising nanoparticle content, and is stronger on E. coli. The approach used in this work is a simple, scalable, and efficient method to improve the performance of PEEK/ZnO nanocomposites for use in biomedical applications such as trauma, orthopedics, and spinal implants. © 2014 American Chemical Society. Source

Diez-Pascual A.M.,CSIC - Institute of Polymer Science and Technology | Diez-Vicente A.L.,Airbus
ACS Applied Materials and Interfaces

Biodegradable nanocomposites were prepared by adding ZnO nanoparticles to bacterial polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) via solution casting technique. The morphology, thermal, mechanical, antibacterial, barrier, and migration properties of the nanocomposites were analyzed. The nanoparticles were uniformly dispersed within PHBV without the aid of coupling agents, and acted effectively as nucleating agents, raising the crystallization temperature and the level of crystallinity of the matrix while decreasing its crystallite size. A gradual rise in thermal stability was found with increasing ZnO loading, since the nanofillers hinder the diffusion of volatiles generated during the decomposition process. The nanocomposites displayed superior stiffness, strength, toughness, and glass transition temperature, whereas they displayed reduced water uptake and oxygen and water vapor permeability compared to the neat biopolymer, related to the strong matrix-nanofiller interfacial adhesion attained via hydrogen bonding interactions. At an optimal concentration of 4.0 wt % ZnO, the tensile strength and Young's and storage moduli showed a maximum that coincided with the highest crystallinity and the best barrier properties. PHBV/ZnO films showed antibacterial activity against human pathogen bacteria, and the effect on Escherichia coli was stronger than on Staphylococcus aureus. The overall migration levels of the nanocomposites in both nonpolar and polar simulants dropped upon increasing nanoparticle content, and were well below the limits required by the current normative for food packaging materials. These sustainable nanomaterials with antimicrobial function are very promising to be used as containers for beverage and food products as well as for disposable applications like cutlery or overwrap films. © 2014 American Chemical Society. Source

Salavagione H.J.,CSIC - Institute of Polymer Science and Technology
Journal of Materials Chemistry A

A decade after scientists from Manchester University isolated a single graphene sheet, the development of a method for mass-scale production of graphene of a similar quality to that obtained, and the implementation of a modular chemical route to incorporate graphene into multicomponent/ multifunctional materials are still fundamental challenges. The methods for graphene production and the synthetic procedures for its modification are limited to a handful of established methodologies, each with important limitations. In this manuscript a non-conventional electrochemical method for the preparation of high-quality graphene, and a recently reported general chemical approach for graphene functionalization through thiol-ene click reactions are highlighted. © the Partner Organisations 2014. Source

Leon R.,University of Cambridge | Garcia A.G.,Autonomous University of Madrid | Garcia A.G.,Hospital Universitario Of La Princesa | Marco-Contelles J.,CSIC - Institute of Polymer Science and Technology
Medicinal Research Reviews

With 27 million cases worldwide documented in 2006, Alzheimer's disease (AD) constitutes an overwhelming health, social, economic, and political problem to nations. Unless a new medicine capable to delay disease progression is found, the number of cases will reach 107 million in 2050. So far, the therapeutic paradigm one-compound-one-target has failed. This could be due to the multiple pathogenic mechanisms involved in AD including amyloid β (Aβ) aggregation to form plaques, τ hyperphosphorylation to disrupt microtubule to form neurofibrillary tangles, calcium imbalance, enhanced oxidative stress, impaired mitochondrial function, apoptotic neuronal death, and deterioration of synaptic transmission, particularly at cholinergic neurons. Approximately 100 compounds are presently been investigated directed to single targets, namely inhibitors of β and γ secretase, vaccines or antibodies that clear Aβ, metal chelators to inhibit Aβ aggregation, blockers of glycogen synthase kinase 3β, enhancers of mitochondrial function, antioxidants, modulators of calcium-permeable channels such as voltage-dependent calcium channels, N-methyl-D-aspartate receptors for glutamate, or enhancers of cholinergic neurotransmission such as inhibitors of acetylcholinesterase or butyrylcholinesterase. In view of this complex pathogenic mechanisms, and the successful treatment of chronic diseases such as HIV or cancer, with multiple drugs having complementary mechanisms of action, the concern is growing that AD could better be treated with a single compound targeting two or more of the pathogenic mechanisms leading to neuronal death. This review summarizes the current therapeutic strategies based on the paradigm one-compound-various targets to treat AD. A treatment that delays disease onset and/or progression by 5 years could halve the number of people requiring institutionalization and/or dying from AD. © 2011 Wiley Periodicals, Inc. Source

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