Surface modulation of single-walled carbon nanotubes for selective bacterial cell agglutination.

BACKGROUND: Bacterial resistance to antibiotics is one of the biggest challenges facing medicine today. Anti-adhesive therapy, using inhibitors of bacterial adhesion to epithelial cells, one of the first stages of infection, is a promising approximation in this area. The size, shape, number of sugar and their placement are variables that have to be taken into account in order to develop multivalent systems able to inhibit the bacterial adhesion based on sugar-lectin interaction. MATERIALS AND METHODS: In the present work we report a modular approach for the synthesis of water-soluble 1D-carbon nanotube-sugar nanoconstructs, with the necessary flexibility to allow an efficient sugar-lectin interaction. The method is based on the reaction of aryl diazonium salts generated in situ from aniline-substituted mannose and lactose derivatives with single wall carbon nanotubes (SWCNTs) sidewalls. RESULTS: Two hybrid nanosystems, I-II, exposing mannose or lactose and having a tetraethylene glycol spacer between the sugar and the nanotube sidewall were rapidly assembled and adequately characterized. The sweet nano-objects were then tested for their ability to agglutinate and selectively inhibit the growth of uropathogenic Escherichia coli. These studies have shown that nanosystem I, exposing mannose on the nanotube surface is able to agglutinate and to inhibit the bacterial growth unlike nano-objects II exposing lactose. CONCLUSION: The results reported constitute a proof of principle in using mannose-coated 1D-carbon nanotubes as antiadhesive drugs that compete for FimH binding and prevent the uropathogenic bacteria from adhering to the urothelial surface.

Light-controlled morphologies of self-assembled triarylamine-fullerene conjugates.

A family of triarylamine-fullerene conjugates has been synthesized and shown to self-assemble upon light stimulation in chlorinated solvents. This light-induced process primarily involves excitation of triarylamine derivatives, which then oxidize and stack with their neutral counterparts to form charge transfer complexes in the form of p-conducting channels, while fullerenes are consequently enforced in coaxial n-conducting columnar arrangements. These supramolecular heterojunctions can be organized over very long distances in micrometric fibers when a controlled amount of photons is provided from a white light source to initiate the process. Surprisingly, when sunlight or UV light is used instead, the nanostructuration leads to monodisperse spherical objects due to the nature of the nucleation-growth process involved in the stacks formation. This control over the supramolecular morphology of organic self-assemblies using the nature of light is of general interest for the design of functional responsive materials.

pH and light-controlled self-assembly of bistable [c2] daisy chain rotaxanes.

A logic gate based on a bistable [c2] daisy chain rotaxane decorated with lateral triarylamine units is described, giving rise to an INHIBIT logic function using proton concentration and light as inputs, and producing dual color change and supramolecular self-assembly as outputs.

Supramolecular self-assembly and radical kinetics in conducting self-replicating nanowires.

By using a combination of experimental and theoretical tools, we elucidate unique physical characteristics of supramolecular triarylamine nanowires (STANWs), their packed structure, as well as the entire kinetics of the associated radical-controlled supramolecular polymerization process. AFM, small-angle X-ray scattering, and all-atomic computer modeling reveal the two-columnar "snowflake" internal structure of the fibers involving the π-stacking of triarylamines with alternating handedness. The polymerization process and the kinetics of triarylammonium radicals formation and decay are studied by UV-vis spectroscopy, nuclear magnetic resonance and electronic paramagnetic resonance. We fully describe these experimental data with theoretical models demonstrating that the supramolecular self-assembly starts by the production of radicals that are required for nucleation of double-columnar fibrils followed by their growth in double-strand filaments. We also elucidate nontrivial kinetics of this self-assembly process revealing sigmoid time dependency and complex self-replicating behavior. The hierarchical approach and other ideas proposed here provide a general tool to study kinetics in a large number of self-assembling fibrillar systems.

Heteroleptic copper(I) complexes prepared from phenanthroline and bis-phosphine ligands.

Preparation of [Cu(NN)(PP)](+) derivatives has been systematically investigated starting from two libraries of phenanthroline (NN) derivatives and bis-phosphine (PP) ligands, namely, (A) 1,10-phenanthroline (phen), neocuproine (2,9-dimethyl-1,10-phenanthroline, dmp), bathophenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 2,9-diphenethyl-1,10-phenanthroline (dpep), and 2,9-diphenyl-1,10-phenanthroline (dpp); (B) bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)benzene (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppFc), and bis[(2-diphenylphosphino)phenyl] ether (POP). Whatever the bis-phosphine ligand, stable heteroleptic [Cu(NN)(PP)](+) complexes are obtained from the 2,9-unsubstituted-1,10-phenanthroline ligands (phen and Bphen). By contrast, heteroleptic complexes obtained from dmp and dpep are stable in the solid state, but a dynamic ligand exchange reaction is systematically observed in solution, and the homoleptic/heteroleptic ratio is highly dependent on the bis-phosphine ligand. Detailed analysis revealed that the dynamic equilibrium resulting from ligand exchange reactions is mainly influenced by the relative thermodynamic stability of the different possible complexes. Finally, in the case of dpp, only homoleptic complexes were obtained whatever the bis-phosphine ligand. Obviously, steric effects resulting from the presence of the bulky phenyl rings on the dpp ligand destabilize the heteroleptic [Cu(NN)(PP)](+) complexes. In addition to the remarkable thermodynamic stability of [Cu(dpp)2]BF4, this negative steric effect drives the dynamic complexation scenario toward almost exclusive formation of homoleptic [Cu(NN)2](+) and [Cu(PP)2](+) complexes. This work provides the definitive rationalization of the stability of [Cu(NN)(PP)](+) complexes, marking the way for future developments in this field.

Glyconanosomes: disk-shaped nanomaterials for the water solubilization and delivery of hydrophobic molecules.

Herein, we describe the first report on a new class of disk-shaped and quite monodisperse water-soluble nanomaterials that we named glyconanosomes (GNS). GNSs were obtained by sliding out the cylindrical structures formed upon self-organization and photopolymerization of glycolipid 1 on single-walled carbon nanotube (SWCNT) sidewalls. GNSs present a sheltered hydrophobic inner cavity formed by the carbonated tails, surrounded by PEG and lactose moieties. The amphiphilic character of GNSs allows the water solubility of insoluble hydrophobic cargos such as a perylene-bisimide derivative, [60]fullerene, or the anti-carcinogenic drug camptothecin (CPT). GNS/C60 inclusion complexes are able to establish specific interactions between peanut agglutinin (PNA) lectin and the lactose moiety surrounding the complexes, while CPT solubilized by GNS shows higher cytotoxicity toward MCF7-type breast cancer cells than CPT alone. Thus, GNS represents an attractive extension of nanoparticle-based drug delivery systems.

Advances in supramolecular electronics - from randomly self-assembled nanostructures to addressable self-organized interconnects.

Supramolecular organic electronics rests on the use of bottom-up chemical self-assembly processes in order to design conducting components on the 5-100 nm scale. The challenges in this field are both the construction of 1D-nanostructures displaying optimized transport properties and their precise connections to electrodes. The present Research News highlights important advances in such materials regarding their electrical performances, from semiconductors to organic metals, but also regarding their processability. In particular, by externally controlling light-responsive supramolecular polymerization processes, and by using appropriate methods of casting with an applied electric field, it becomes possible to pre-determine the accurate positioning of organic interconnects within patterned nano-circuitry. These strategies using external stimuli to obtain addressability, thus hold promising alternatives to other conducting materials such as carbon nanotubes for further technological applications in nanosciences.

A stable and strongly luminescent dinuclear Cu(I) helical complex prepared from 2-diphenylphosphino-6-methylpyridine.

Treatment of 2-diphenylphosphino-6-methylpyridine (dpPyMe) with Cu(CH(3)CN)(4)BF(4) afforded the stable dinuclear Cu(I) complex [Cu(2)(µ-dpPyMe)(3)(CH(3)CN)](BF(4))(2). This compound is a weak emitter in solution, however a remarkably high emission quantum yield (46%) has been found in a rigid matrix at room temperature.

Synthesis and photophysical properties of fullerene-phthalocyanine-porphyrin triads and pentads.

The synthesis and photophysical properties of several fullerene-phthalocyanine-porphyrin triads (1-3) and pentads (4-6) are described. The three photoactive moieties were covalently connected in an one-step synthesis through 1,3-dipolar cycloaddition to C(60) of the corresponding azomethine ylides generated in situ by condensation reaction of a substituted N-porphyrinylmethylglycine derivative and an appropriated formyl phthalocyanine or a diformyl phthalocyanine derivative, respectively. ZnP-C(60)-ZnPc (3), (ZnP)(2)-ZnPc-(C(60))(2) (6), and (H(2)P)(2)-ZnPc-(C(60))(2) (5) give rise upon excitation of their ZnP or H(2)P components to a sequence of energy and charge-transfer reactions with, however, fundamentally different outcomes. With (ZnP)(2)-ZnPc-(C(60))(2) (6) the major pathway is an highly exothermic charge transfer to afford (ZnP)(ZnP(.+))-ZnPc-(C(60)(.-))(C(60)). The lower singlet excited state energy of H(2)P (i.e., ca. 0.2 eV) and likewise its more anodic oxidation (i.e., ca. 0.2 V) renders the direct charge transfer in (H(2)P)(2)-ZnPc-(C(60))(2) (5) not competitive. Instead, a transduction of singlet excited state energy prevails to form the ZnPc singlet excited state. This triggers then an intramolecular charge transfer reaction to form exclusively (H(2)P)(2)-ZnPc(.+)-(C(60)(.-))(C(60)). A similar sequence is found for ZnP-C(60)-ZnPc (3).

Charge separation in a covalently-linked phthalocyanine-oligo(p-phenylenevinylene)-C60 system. Influence of the solvent polarity.

A photo- and redoxactive system ZnPc-oPPV-C(60)2, in which the photoexcited state electron donor - zinc phthalocyanine - and the ground state electron acceptor - C(60) - are connected by a oligo(p-phenylenevinylene) (oPPV) spacer, has been synthesized in a multi-step synthesis by means of two consecutive Wadsworth-Horner-Emmons and a dipolar 1,3-cycloaddition reactions as key steps. The simpler system ZnPc-C(60)1 has also been prepared as a reference model for photophysical studies. In this regards, the photophysical investigations by means of fluorescence, flash photolysis, and transient-absorption spectroscopy have manifested a clear dependence between charge transfer kinetics and spatial arrangement. In both systems, intramolecular charge separation evolves from the photoexcited ZnPc and yields the ZnPc(·+)/C(60)(·-) radical ion pairs. Interestingly, the ZnPc(·+)/C(60)(·-) radical ion pair lifetimes and quantum yields are strongly impacted by the solvent polarity and the distance. To this end, maximum radical ion pair lifetimes of 2900 and 5530 ps were found in anisol for 1 and 2, respectively.

Synthesis, photophysical and electrochemical characterization of phthalocyanine-based poly(p-phenylenevinylene) oligomers.

The synthesis of two poly(p-phenylenevinylene) oligomers (oPPV) laterally substituted by phthalocyanines (Pc) is described. The preparation of Pc-based oligomers and was accomplished by means of Knoevenagel and Wadsworth-Horner-Emmons reactions, respectively. Diformylphthalocyanine was employed as a monomer in these reactions, thus providing functionalised conjugated oligomers upon reaction with the corresponding co-monomers, and . Photophysical and electrochemical experiments have been carried out with both oligomeric derivatives, revealing excited state interactions such as transduction of singlet excited state energy.

Structure-function relationships in unsymmetrical zinc phthalocyanines for dye-sensitized solar cells.

A series of unsymmetrical zinc phthalocyanines bearing an anchoring carboxylic function linked to the phthalocyanine ring through different spacers were designed for dye-sensitised solar cells (DSSC). The modification of the spacer group allows not only a variable distance between the dye and the nanocrystalline TiO(2), but also a distinct orientation of the phthalocyanine on the semiconductor surface. The photovoltaic data show that the nature of the spacer group plays a significant role in the electron injection from the photo-excited dye into the nanocrystalline TiO(2) semiconductor, the recombination rates and the efficiency of the cells. The incident monochromatic photon-to-current conversion efficiency (IPCE) for phthalocyanines bearing an insulating spacer is as low as 9%, whereas for those with a conducting spacer an outstanding IPCE 80% was obtained.

Strength enhancement of nanostructured organogels through inclusion of phthalocyanine-containing complementary organogelator structures and in situ cross-linking by click chemistry.

Stable photoactive organogels were successfully prepared by a two-step sequence involving: 1) formation of thermoreversible organogels by use of a combination of low-molecular-weight organogelators (LMOGs) and ZnII-phthalocyanine (ZnII-Pc) moieties containing complementary organogelator structures, and 2) strength enhancement of the gels by in situ cross-linking with the aid of CuI-catalysed azide-alkyne [3+2] cycloadditions (CuAACs). The optimum click reaction was carried out between a flexible C6 aliphatic diazide and a suitable dialkyne (molar ratio 1:1) added in a low proportion relative to the organogelator system [LMOG+ZnIIPc]. The dialkyne unit was incorporated into a molecule resembling the LMOGs structure in such a way that it could also participate in the self-assembly of [LMOG+ZnIIPc]. The significant compatibility of the multicomponent photoactive organogels towards this strengthening through CuAACs allowed their sol-to-gel transition temperatures (Tgel) to be enhanced by up to 15 degrees C. The Tgel values estimated by the "inverse flow method" were in good agreement with the values obtained by differential scanning calorimetry (DSC). Rheological measurements confirmed the viscoelastic, rigid, and brittle natures of all Pc-containing gels. Transmission and scanning electron microscopy (TEM, SEM) and atomic force microscopy (AFM) revealed the fibrilar nature of the gels and the morphological changes upon cross-linking by CuAAC. Emission of a red luminescence from the dry nanoscale fibrous structure-due to the self-assembly of the Pc-containing compounds in the organogel fibres-was directly observed by confocal laser scanning microscopy (CLSM). The optical properties were studied by UV/Vis and fluorescence spectroscopy. Fluorescence, Fourier-transform infrared (FTIR) and circular dichroism (CD) measurements were also carried out to complete the physicochemical characterization of selected gels. As a proof of concept, two different organogelators (cholesterol- and diamide-based LMOGs) were successfully used to validate the general strategy.

Effect of coadsorbent on the photovoltaic performance of zinc pthalocyanine-sensitized solar cells.

The effect of chenodeoxycholic acid as a coadsorbent on TiO 2 nanocrystalline solar cells incorporating phthalocyanine sensitizers was studied under various conditions. Adding chenodeoxycholic acid onto TiO 2 nanoparticles not only reduces the adsorption of phthalocyanine sensitizers but also prevents sensitizer aggregation, leading to different photovoltaic performance. The inspection of IPCE and absorption spectra showed that the load of phthalocyanine sensitizers is strongly dependent on the molar concentration of chenodeoxycholic acid coadsorbent. The open circuit voltage of the solar cells with chenodeoxycholic acid coadsorbent increases due to the enhanced electron lifetime in TiO 2 nanoparticles coupled with the band edge shift of TiO 2 to negative potentials.

[Training in cardiopulmonary reanimation with early defibrillation to nurses from the 7th area of Madrid]. / Formación en reanimación cardiopulmonar básica con desfibrilación precoz a enfermeros/as del área 7 de Madrid.

UNLABELLED: Ventricular fibrillation and ventricular tachicardia without pulse are the most frequent causes of suddenly death, therefore, it was considered that training hospitals and healthcentre nurses in identifying arritms and using properly the defibrilators was necessary. It was made by practical-theoric courses. The main aim of this study has been to know does the nurses value these type of courses and its repercussion on their level of knowledge. This is a descriptive study. The course consisted of 2 parts, one theoric and other practical. The valuation was made with a practical exam (A, B o C, being C a fail) and the other was written. To obtain the certificate of the course, you need to get at least 70% in the written part, and an A or a B in the practical exam. An exam was set at the beginning of the course and other at the end of it, in order to see the improvement. To value the course, we passed one anonimous poll, for this, it was used one scale from 1-5. we have gone 8 courses with 226 pupils, and the 74.3% of them, have passed. The level of knowledges has considerably increased p < 0.0001 the level of satisfaction was 4.7 0.5, of the teachers was of 4.6 0.5 and theirs enthusiasm on the course was 4.7 0.6. For them, theirs level of theorical and practical knowledges were 2.7 0.7 and 2.5 0.7 respectively. CONCLUSIONS: 1) Nurses have had a great interest in this course. 2) After the course, the level of knowledge was increased. 3) The califications of the pupils on the teachers and the course has been high. 4) The training of nursery in RCP and early defibrillation is absolutely essential as it is shawn in their low level of theorical and practical knowledge.

Formación en reanimacióncardiopulmonar básica condesfibrilación precoz aenfermeros/as del área 7de Madrid / Training in cardiopulmonary reanimation with early defibrillation to nurses from the 7th area of Madrid

La fibrilación ventricular y la taquicardia ventricular sin pulso son la causa más frecuente de muerte súbita, por ello se consideró necesario formar a la enfermería de hospitalización y ambulatorios, en la identificación de estas arritmias y en la utilización del desfibrilador, mediante cursos teórico-prácticos. El objetivo ha sido conocer cómo valora la enfermería este tipo de cursos y su repercusión en el nivel de conocimientos. Estudio descriptivo. El curso constó de 2 partes, una teórica y otra práctica. La evaluación se realizó mediante examen práctico (A, B o C, siendo C suspenso) y escrito. Para obtener la certificación del curso, debían obtener una puntuación superior o igual al 70 por ciento en el examen escrito y "A o B" en el práctico. Para valorar la probable mejoría en el nivel de conocimientos, se realizó un examen al inicio del curso, que fue comparado con el posterior. La evaluación del curso y profesorado se realizó mediante encuesta anónima, se utilizó una escala de valoración del 1 al 5. Se han impartido 8 cursos con un total de 226 alumnos, han obtenido certificado de capacitación el 74,3 por ciento. El aumento en el nivel de conocimientos ha sido estadísticamente significativo p > 0,0001. El nivel de satisfacción obtuvo una media de 4,7 ñ 0,5, el profesorado 4,6 ñ 0,5 y su interés por el curso fue 4,7 ñ 0,6. Según ellos, su nivel de conocimientos teóricos y prácticos fue 2,7 ñ 0,7 y 2,5 ñ 0,7 respectivamente. Como conclusión podemos decir: 1) El interés de la enfermería en este curso es alto; 2) Existe un aumento de conocimientos tras la realización del curso; 3) La valoración que el alumno hace tanto del curso como del profesorado es alto; 4) La formación de la enfermería en RCP y desfibrilación precoz es imprescindible a la vista de los escasos conocimientos teóricos y prácticos que tienen (AU)