b-Chitinous scaffolds isolated from the skeleton of marine cephalopod Sepia officinalis were used as a template for the in vitro formation of ZnO under conditions (70 C) which are extreme for biological materials. Novel b-chitin/ZnO film-like composites were prepared for the first time by hydrothermal synthesis, and were thoroughly characterized using numerous analytical methods including Raman spectroscopy, HR-TEM and XRD. We demonstrate the growth of hexagonal ZnO nanocrystals on the b-chitin substrate. Our chitin/ZnO composites presented in this work show antibacterial properties against Gram positive bacteria and can be employed for development of inorganic-organic wound dressing materials.

This work presents an extreme biomimetics route for the creation of nanostructured biocomposites utilizing a chitinous template of poriferan origin. The specific thermal stability of the nanostructured chitinous template allowed for the formation under hydrothermal conditions of a novel germanium oxide− chitin composite with a defined nanoscale structure. Using a variety of analytical techniques (FTIR, Raman, energy dispersive X-ray (EDX), near-edge X-ray absorption fine structure (NEXAFS), and photoluminescence (PL) spectroscopy, EDS-mapping, selected area for the electron diffraction pattern (SAEDP), and transmission electron microscopy (TEM)), we showed that this bioorganic scaffold induces the growth of GeO 2 nanocrystals with a narrow (150-300 nm) size distribution and predominantly hexagonal phase, demonstrating the chitin template's control over the crystal morphology. The formed GeO 2 -chitin composite showed several specific physical properties, such as a striking enhancement in photoluminescence exceeding values previously reported in GeO 2 -based biomaterials. These data demonstrate the potential of extreme biomimetics for developing new-generation nanostructured materials.

Fabrication of biomimetic materials and scaffolds is usually a micro- or even nanoscale process; however, most testing and all manufacturing require larger-scale synthesis of nanoscale features. Here, we propose the utilization of naturally prefabricated three-dimensional (3D) spongin scaffolds that preserve molecular detail across centimeter-scale samples. The fine-scale structure of this collagenous resource is stable at temperatures of up to 1200°C and can produce up to 4 × 10–cm–large 3D microfibrous and nanoporous turbostratic graphite. Our findings highlight the fact that this turbostratic graphite is exceptional at preserving the nanostructural features typical for triple-helix collagen. The resulting carbon sponge resembles the shape and unique microarchitecture of the original spongin scaffold. Copper electroplating of the obtained composite leads to a hybrid material with excellent catalytic performance with respect to the reduction of p-nitrophenol in both freshwater and marine environments.

Diatoms are considered unicellular eukaryotic organisms exclusively depositing biogenic silica. Heretofore there has been no report of calcifi cation by these algae. Here it is shown that calcium carbonate within the stalks of Didymosphenia geminata , a nuisance species that has prolifi cally colonized streams and rivers globally, is biogenic in origin and occurs as a network of calcite nanofi bers. The nanofi brous framework in the mineralized polysaccharide matrix imparts mechanical support to the stalks, providing stability in variable fl ow conditions. The results demonstrate that D. geminata possesses cellular and periplasmic carbonic-anhydrases that contribute to carbon fi xation and biomineralization, respectively. The activity of external carbonic-anhydrase was more than 50% of the total activity, which points to its role in anchoring this bioeroding diatom on hard surfaces. The fi rst evidence of multiphase biomineralization by diatoms that deposit both biogenic silica and crystalline biogenic calcite which are imparting distinct functional advantage to the organism is provided.

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Chitin of poriferan origin is a unique and thermostable biological material. It also represents an example of a renewable materials source due to the high regeneration ability of Aplysina sponges under marine ranching conditions. Chitinous scaffolds isolated from the skeleton of the marine sponge Aplysina aerophoba were used as a template for the in vitro formation of Fe 2 O 3 under conditions (pH $ 1.5, 90 C) which are extreme for biological materials. Novel chitin-Fe 2 O 3 three dimensional composites, which have been prepared for the first time using hydrothermal synthesis, were thoroughly characterized using numerous analytical methods including Raman spectroscopy, XPS, XRD, electron diffraction and HR-TEM. We demonstrate the growth of uniform Fe 2 O 3 nanocrystals into the nanostructured chitin substrate and propose a possible mechanism of chitin-hematite interactions. Moreover, we show that composites made of sponge chitin-Fe 2 O 3 hybrid materials with active carbon can be successfully used as electrode materials for electrochemical capacitors.

The fabrication and characterization of an Au-free Ti/Al/TiN (20/100/100 nm) contact stack to unintentionally doped n-GaN with TiN serving as the diffusion barrier is presented. Sputter deposition and lift-off in combination with post deposition annealing at 850 °C are used for contact formation. After annealing, contact shows ohmic behavior to n-GaN and a specific contact resistivity of 1.60 × 10−3 Ω cm2. To understand the contact formation on the microscopic scale, the contact was characterized by current–voltage measurements, linear transmission line method, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results show the formation of Ti-N bonds at the GaN/Ti interface in the as-deposited stack. Annealing leads to diffusion of Ti, Al, Ga, and N, and the remaining metallic Ti is fully consumed by the formation of the intermetallic tetragonal Al3Ti phase. Native oxide from the GaN surface is trapped during annealing and accumulated in the Al interlayer. The TiN capping layer, however, was chemically stable during annealing. It prevented oxidation of the Ti/Al contact bilayer successfully and thus proved to be a well suitable diffusion barrier with ideal compatibility to the Ti/Al contact metallization.

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