Publications by authors named "F Niemeyer"

Article Synopsis
  • Ultrasmall silver nanoparticles (2 nm) were created using sodium borohydride and stabilized with the ligand glutathione, leading to both silver nanoparticles and fluorescing silver nanoclusters.
  • Over time, the nanoclusters degrade while glutathione is released from the particles, contributing to the formation of silver sulfide and resulting in major changes to the particle composition.
  • Analyses showed that these transformations, which significantly influence the nanomaterials' toxicity and properties, are not detectable by common imaging techniques, indicating that fresh nanoparticles are more toxic than aged ones due to the presence of silver clusters.
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Inorganic polyphosphate, a linear polymer of orthophosphate residues linked by phosphoanhydride bonds, occurs in all three domains of life and plays a diverse and prominent role in metabolism and cellular regulation. While the polyphosphate metabolism and its physiological significance have been well studied in bacteria and eukaryotes including human, there are only few studies in archaea available so far. In Crenarchaeota including members of , the presence of polyphosphate and degradation via exopolyphosphatase has been reported and there is some evidence for a functional role in metal ion chelation, biofilm formation, adhesion and motility, however, the nature of the crenarchaeal polyphosphate kinase is still unknown.

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Ultrasmall nanoparticles (diameter 2 nm) of silver, platinum, and bimetallic nanoparticles (molar ratio of Ag:Pt 0:100; 20:80; 50:50; 70:30; 100:0), stabilized by the thiolated ligand glutathione, were prepared and characterized by transmission electron microscopy, differential centrifugal sedimentation, X-ray photoelectron spectroscopy, small-angle X-ray scattering, X-ray powder diffraction, and NMR spectroscopy in aqueous dispersion. Gold nanoparticles of the same size were prepared as control. The particles were fluorescently labeled by conjugation of the dye AlexaFluor-647 via copper-catalyzed azide-alkyne cycloaddition after converting amine groups of glutathione into azide groups.

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In this contribution we report on a novel approach towards luminescent light-responsive ligands. To this end, cyanostilbene- guanidiniocarbonyl-pyrrole hybrids were designed and investigated. Merging of a luminophore with a supramolecular bioactive ligand bears numerous advantages by overcoming the typical drawbacks of drug-labelling, influencing the overall performance of the active species by attachment of a large luminophore.

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Article Synopsis
  • The study explores the factors influencing fracture healing and uses simulation-based workflows to predict potential non-unions in patients.
  • It introduces a new patient-specific simulation tool that integrates clinical data to assess fracture healing, applying it to two cases of non-union post-fracture fixation.
  • The results showcased the simulation's effectiveness in predicting non-unions but highlighted a discrepancy in healing rates that necessitates further validation for improved accuracy, especially for biologically complex cases.
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