The cuticle of mussel byssal threads is a robust natural coating that combines high extensibility with high stiffness and hardness. In this study, fluorescence microscopy and elemental analysis were exploited to show that the 3,4-dihydroxyphenyl-L-alanine (dopa) residues of mussel foot protein-1 colocalize with Fe and Ca distributions in the cuticle of Mytilus galloprovincialis mussel byssal threads. Chelated removal of Fe and Ca from the cuticle of intact threads resulted in a 50% reduction in cuticle hardness, and thin sections subjected to the same treatment showed a disruption of cuticle integrity. Dopa-metal complexes may provide significant interactions for the integrity of composite cuticles deformed under tension.

In situ sol‐gel polymerization is demonstrated for fabricating transparent poly(methyl methacrylate) (PMMA)‐ZnO quantum dot (QD)‐ hybrid materials in bulk dimension. The transparent PMMA‐ZnO QD hybrid materials exhibit enhanced UV‐shielding effects in the entire UV range, even at concentrations as low as 0.02 wt %.

Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials.

Bismuth telluride (Bi 2 Te 3 ) is the best-known commercially used thermoelectric material in the bulk form for cooling and power generation applications at ambient temperature. However, its dimensionless figure-of-merit-ZT around 1 limits the large-scale industrial applications. Recent studies indicate that nanostructuring can enhance ZT while keeping the material form of bulk by employing an advanced synthetic process accompanied with novel consolidation techniques. Here, we report on bulk nanostructured (NS) undoped Bi 2 Te 3 prepared via a promising chemical synthetic route. Spark plasma sintering has been employed for compaction and sintering of Bi 2 Te 3 nanopowders, resulting in very high densification (>97%) while preserving the nanostructure. The average grain size of the final compacts was obtained as 90 AE 5 nm as calculated from electron micrographs. Evaluation of transport properties showed enhanced Seebeck coefficient (À120 mV K À1 ) and electrical conductivity compared to the literature state-of-the-art (30% enhanced power factor), especially in the low temperature range. An improved ZT for NS bulk undoped Bi 2 Te 3 is achieved with a peak value of $1.1 at 340 K.

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a b s t r a c t l-lysine coated iron oxide (LCIO) nanoparticles were synthesized by a co-precipitation method in the presence of amino acid. XRD analysis confirmed the presence of cubic magnetite phase with an average crystallite size of 8 ± 4 nm. Particle size estimated from TEM, by log-normal fitting, is ∼114 nm. The difference between the crystallite size from XRD and particle size from TEM indicates polycrystalline nature of synthesized particles. FT-IR show that the binding of l-lysine on the surface of iron oxide through carboxyl groups is via unidentate linkage. The presence of l-lysine on iron oxide is also confirmed by zeta potential measurements on LCIO nanoparticles, revealing a partial coverage of iron oxide with l-lysine. In order to obtain chemically stable, well-dispersed and uniform sized nanoparticles, amino acids are suitable because they play a very important role in the body. Conductivity measurements were performed to investigate the influence of the coating on the conduction characteristics of iron oxide and results show the existence of a hopping conduction mechanism. Magnetic transition is observed at ∼70 • C for uncoated iron oxide and LCIO samples. Frequency (1 Hz to 3 MHz) and temperature (290-420 K) dependant AC conductivity measurements have resulted in AC activation energies between 0.048 and 0.041 eV for uncoated and 0.050-0.044 eV for LCIO nanoparticles. Temperature-dependant DC resistivity measurements of iron oxide and LCIO at high temperatures resulted in the DC activation energies of 0.22 and 0.43 eV respectively. The higher activation energy value for LCIO is the result of coating by insulating l-lysine layer.

Core–shell magnetic nanostructures (MNS) such as Fe3O4–SiOx, are being explored for their potential applications in biomedicine, such as a T2 (dark) contrast enhancement agent in magnetic resonance imaging (MRI). Herein, we present the effect of silica shell thickness on its r2 relaxivity in MRI as it relates to other physical parameters. In this effort initially, monodispersed Fe3O4 MNS (nominally 9 nm size) were synthesized in organic phase via a simple chemical decomposition method. To study effect of shell thickness of silica of Fe3O4–SiOx core shell on r2 relaxivity, the reverse micro-emulsion process was used to form silica coating of 5, 10 and 13 nm of silica shell around the MNS, while polyhedral oligomeric silsesquioxane was used to form very thin layer on the surface of MNS; synthesized nanostructures were characterized by transmission electron microscopy (TEM) and high resolution TEM (HRTEM), superconducting quantum interference device magnetometry and MRI. Our observation suggests that, with increase in thickness of silica shell in Fe3O4–SiOx core–shell nanostructure, r2 relaxivity decreases. The decrease in relaxivity could be attributed to increased distance between water molecules and magnetic core followed by change in the difference in Larmor frequencies (Dx) of water molecules. These results provide a rational basis for optimization of SiOx-coated MNS for biomedical applications.