SummaryMicrobial biosynthesis of metal nanoparticles as needed in catalysis has shown its theoretical ability as an extremely environmentally friendly production method in the last few years, even though the separation of the nanoparticles is challenging. Biosynthesis, summing up biosorption and bioreduction of diluted metal ions to zero valent metals, is especially ecofriendly, when the bioreactor itself is harmless and needs no further harmful reagents. The cyanobacterium Anabaena cylindrica (SAG 1403.2) is able to form crystalline Au0-nanoparticles from Au3+ ions and does not release toxic anatoxin-a. X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and laser-induced breakdown spectroscopy (LIBS) are applied to monitor the time-dependent development of gold nanoparticles for up to 40 hours. Some vegetative cells (VC) are filled with nanoparticles within minutes, while the extracellular polymeric substances (EPS) of vegetative cells and the heterocyst polysaccharide layer (HEP) are the regions, where the first nanoparticles are detected on most other cells. The uptake of gold starts immediately after incubation and within four hours the average size remains constant around 10 nm. Analyzing the TEM images with an image processing program reveals a wide distribution for the diameter of the nanoparticles at all times and in all regions of the cyanobacteria. Finally, the nanoparticle concentration in vegetative cells of Anabaena cylindrica is about 50% higher than in heterocysts (HC). These nanoparticles are found to be located along the thylakoid membranes.

Efficient biosorption and intracellular accumulation of selected rare earth elements from aqueous solutions by cyanobacteria type Anabaena.

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Amorphous hydrogenated carbon (a-C:H) films are applied 500 nm thick on Si(100) via plasma-enhanced chemical vapor deposition (PECVD) using ethyne. Present plasma conditions enrich the sp 2 -content especially toward the outermost a-C:H layers, which in turn are used to attach a photoactive Ru-polypyridyl complex to the surface. An azo-bridged dinuclear Ru-polypyridyl complex is optimized in synthesis and the final mononuclear fragment attached on a-C:H photochemically under UV-irradiation with concomitant N 2 release. The Ru-polypyridyl complex is characterized by MS, NMR, IR, UV/vis, fluorescence spectroscopy, and time-dependent density functional theory (DFT) calculations. Crystallographic data for the intermediate 4-nitro-2-(pyridin-2-yl)pyridine 1-oxide as essential precursor are established. Morphological characteristics of the a-C:H @ Si and final Ru(complex) @ a-C:H @ Si combinations are determined by atomic force microscopy (AFM) revealing individual grain-like structures. The presence of Ru on the a-C:H @ Si surface is initially verified qualitatively by laser-induced breakdown spectroscopy (LIBS) and by inductively coupled plasma-sector field mass spectrometry (ICP-SF-MS) after chemical digestion. With laser ablation-ICP-MS mapping, full Ru coverage is proven, also revealing inhomogeneities in terms of "Ru hot spots". The current investigation proves the successful attachment of a Ru-complex on a-C:H and indicates a starting point for the development of further material combinations for feasible sunlight to energy conversions. Surface FunctionalizationThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.