The layer-by-layer growth of a surface-attached metal-organic framework (SURMOF), [Cu2(F4bdc)2(dabco)] (F4bdc = tetrafluorobenzene-1,4-dicarboxylate and dabco = 1,4-diazabicyclo-[2.2.2]octane), on carboxylate- and pyridine-terminated surfaces has been investigated by various surface characterization techniques. Particular attention was paid to the dependency of the crystal orientation and morphology on surface functionality, deposition temperature, and first layer order. For the fully oriented deposition of SURMOFs, not only a suitable surface chemistry but also the appropriate temperature has to be chosen. In the case of carboxylate-terminated surfaces, the expected [100] oriented [Cu2(F4bdc)2(dabco)] SURMOF can be achieved at low temperatures (5 °C). In contrast, the predicted [001] oriented SURMOF on pyridine-terminated surface was obtained only at high deposition temperatures (60 °C). Interestingly, we found that rearrangement processes in the very first layer determine the final orientation (distribution) of the growing crystals. These effects could be explained by a surprisingly hampered substitution at the apical position of the Cu2-paddle wheel units, which requires significant thermal activation, as supported by quantum-chemical calculations.
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http://dx.doi.org/10.1021/jacs.5b03948 | DOI Listing |
Microorganisms
December 2024
Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
is a major cause of chronic respiratory infections in patients with cystic fibrosis (CF), with biofilm formation contributing to its persistence and antibiotic resistance. This study aimed to gain insights into the mechanistic action of succinic acid as a ciprofloxacin adjuvant against clinically relevant CF isolates, including small colony variants and mucoid strains, and a ciprofloxacin-resistant strain grown within CF dense mucus. Time-kill assays in artificial CF mucus, along with planktonic and surface-attached biofilm experiments, were used to assess the activity of succinic acid alone and in combination with sublethal ciprofloxacin concentrations.
View Article and Find Full Text PDFMicrob Pathog
February 2025
University of Kragujevac, Faculty of Science, Department of Biology and Ecology, Radoja Domanovića 12, 34000, Kragujevac, Serbia. Electronic address:
Biofilm is a surface-attached community of bacterial cells implicated in the pathogenesis of chronic infections and is highly resistant to antibiotics. New alternatives for controlling bacterial infections have been proposed focusing on the therapeutic properties of medicinal plants. Achillea millefollium (Yarrow) is a widespread plant species that is widely used in traditional medicine, especially for wound healing.
View Article and Find Full Text PDFMicrobiol Spectr
January 2025
Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium.
Unlabelled: There is growing evidence that bacteria encountered in prosthetic joint infections (PJIs) form surface-attached biofilms on prostheses, as well as biofilm aggregates embedded in synovial fluid and tissues. However, models allowing the investigation of these biofilms and the assessment of their antimicrobial susceptibility in physiologically relevant conditions are currently lacking. To address this, we developed a synthetic synovial fluid (SSF2) model and validated this model by investigating growth, aggregate formation, and antimicrobial susceptibility using multiple PJI isolates belonging to various microorganisms.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2024
Department of Molecular Biology, Princeton University, Princeton, NJ 08544.
Surface-attached cells can sense and respond to shear flow, but planktonic (free-swimming) cells are typically assumed to be oblivious to any flow that carries them. Here, we find that planktonic bacteria can transcriptionally respond to flow, inducing expression changes that are beneficial in flow. Specifically, we use microfluidic experiments and quantitative modeling to show that in the presence of flow, planktonic induce shear rate-dependent genes that promote growth in low-oxygen environments.
View Article and Find Full Text PDFNPJ Biofilms Microbiomes
September 2024
School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.
Suspended bacterial aggregates play a central role in ocean biogeochemistry, industrial processes and probably many clinical infections - yet the factors that trigger aggregation remain poorly understood, as does the relationship between suspended aggregates and surface-attached biofilms. Here we show that very low doses of cell-wall targeting antibiotic, far below the minimal inhibitory concentration, can trigger aggregation of Escherichia coli cells. This occurs when a few cells lyse, releasing extracellular DNA - thus, cell-to-cell variability in antibiotic response leads to population-level aggregation.
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