scholarly journals Synthesis, Characterization, and In Situ Antifungal and Cytotoxicity Evaluation of Ascorbic Acid-Capped Copper Nanoparticles

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Ernesto Beltrán-Partida ◽  
Benjamín Valdez-Salas ◽  
Ernesto Valdez-Salas ◽  
Guillermo Pérez-Cortéz ◽  
Nicola Nedev
Keyword(s):  
Ascorbic Acid ◽  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Dark Field ◽  
Industrial Applications ◽  
Dark Field Microscopy ◽  
Antifungal Potential ◽  
Massive Accumulation

The design route, synthesis, and characterization of spherical copper nanoparticles with antifungal potential are reported in the present work. Copper nanoparticles were synthesized by a novel, inexpensive, and eco-friendly chemical reduction method using ascorbic acid as a reductant and stabilizer under reflux conditions. The characterization results showed the formation of homogeneous, dispersed, and stable spherical ascorbic acid-capped copper nanoparticles (CuNPs) with a diameter of 250 nm. The CuNPs exhibited sustained antifungal activity againstCandida albicans(C. albicans) after 24 h and even 48 h of incubation. Using enhanced dark-field microscopy, we presented the in situ interaction between CuNPs andC. albicans. Here, part of the interaction of CuNPs among theC. albicans, studied without the use of any chemical and/or physical fixing method, is discussed. The results indicate that part of the antifungal mechanism involves a promoted adhesion of CuNPs onto the cell wall and a massive accumulation of CuNPs into the fungal cells, concluding in cellular leakage. The cytotoxicity (viability) evaluations indicated that our CuNPs were more biocompatible after comparison to the Cu precursor and triclosan (a commercial antifungal drug). The synthesized CuNPs will open up a new road for their possible use as a potent antimicrobial agent for clinical and industrial applications.

Internalization of hyaluronan by chondrocytes occurs via receptor-mediated endocytosis

1993 ◽  
Vol 106 (1) ◽  
pp. 365-375 ◽  
Author(s):  
Q. Hua ◽  
C.B. Knudson ◽  
W. Knudson
Keyword(s):  
Cell Surface ◽  
Articular Chondrocytes ◽  
Dark Field ◽  
Cartilage Tissue ◽  
Receptor Mediated Endocytosis ◽  
Dark Field Microscopy ◽  
Bovine Articular Chondrocytes ◽  
Hyaluronan Receptors ◽  
Hyaluronan Receptor

Several studies have suggested that chondrocytes must have the capacity to internalize and degrade extracellular hyaluronan. In the present study we show direct evidence that hyaluronan is, in fact, endocytosed by chondrocytes and that the endocytosis is mediated via cell surface CD44/hyaluronan receptors. Cultures of bovine articular chondrocytes as well as rat chondrosarcoma chondrocytes were incubated with either fluorescein- or 3H-labeled hyaluronan. Intense binding and accumulation of labeled hyaluronan was visualized by fluorescence microscopy or bright-field/dark-field microscopy following autoradiography. Cell surface hyaluronan was removed with either trypsin or Streptomyces hyaluronidase in order to distinguish and quantify intracellular endocytosed hyaluronan. Labeled hyaluronan was visualized within small discrete intracellular vesicles distributed throughout the cytoplasm. Binding and endocytosis of fluorescein- or 3H-labeled hyaluronan was totally blocked by the addition of excess unlabeled hyaluronan or hyaluronan hexasaccharides, competitive inhibitors of hyaluronan/hyaluronan receptor interactions. Binding and endocytosis was also blocked by the addition of anti-CD44 monoclonal antibodies. Characterization of endocytosed 3H-labeled hyaluronan demonstrated that a significant portion of the hyaluronan was degraded by both the bovine articular and rat chondrosarcoma chondrocytes. Interestingly, a higher proportion of bound hyaluronan was internalized by the bovine chondrocytes. Therefore, hyaluronan receptor-mediated endocytosis and degradation of hyaluronan may provide a critical link to the maintenance and homeostasis of cartilage tissue.

Engineering and Characterization of Resonant Optical Antennas

2010 ◽  
Vol 1248 ◽  
Author(s):  
Matthias D. Wissert ◽  
Andreas W. Schell ◽  
Konstantin S. Ilin ◽  
M. Siegel ◽  
U. Lemmer ◽  
...  
Keyword(s):  
Electron Beam Lithography ◽  
Dark Field ◽  
Optical Antennas ◽  
Dipole Antennas ◽  
Split Ring ◽  
Dark Field Microscopy ◽  
Scattering Spectra ◽  
Coupled Structures ◽  
Spectral Redshift

AbstractResonant optical dipole antennas, consisting either of two arms coupled by a small gap or of a single, uncoupled arm only, are fabricated by the application of electron beam lithography and gold evaporation. Using dark-field microscopy, scattering spectra of structures with varied antenna arm length and varied gap size are obtained. The results show not only a spectral redshift for coupled structures compared to single arm structures, but also that the far-field scattering intensity is significantly higher for two arm structures with gap. In addition to the dipole structures, first fabrication results on quadrupole antennas and split-ring antennas are presented, offering novel pathways for an enhancement of the optical response function.

scholarly journals Molecular Epidemiology of Oral Treponemes Associated with Periodontal Disease

1998 ◽  
Vol 36 (5) ◽  
pp. 1399-1403 ◽  
Author(s):  
Annette Moter ◽  
Carina Hoenig ◽  
Bong-Kyu Choi ◽  
Birgit Riep ◽  
Ulf B. Göbel
Keyword(s):  
In Situ Hybridization ◽  
Alveolar Bone ◽  
Blot Hybridization ◽  
Dark Field ◽  
Causative Role ◽  
Oligonucleotide Probes ◽  
Dot Blot ◽  
Dark Field Microscopy ◽  
Healthy Control

Periodontitis, a disease responsible for tooth loss worldwide, is characterized by chronic inflammation of the periodontium, eventually leading to destruction of periodontal ligaments and supporting alveolar bone. Spirochetes, identified by dark-field microscopy as being the most predominant bacteria in advanced lesions, are thought to play a causative role. Various spirochetal morphotypes were observed, but most of these morphotypes are as yet uncultivable. To assess the role of these organisms we designed oligonucleotide probes for the identification of both cultivable and so far uncultivable spirochetes in periodontitis patients. Subgingival plaque specimens taken from diseased sites (n = 200) and healthy control sites (n = 44) from 53 patients with rapidly progressive periodontitis (RPP) were submitted to direct in situ hybridization or dot blot hybridization after prior amplification with eubacterial primers. Spirochetes were found in all patients, but their distributions varied considerably. Parallel use of oligonucleotide probes specific for cultivable or so far uncultivable treponemes suggested the presence of novel yet unknown organisms at a high frequency. These uncultivable treponemes were visualized by fluorescence in situ hybridization, and their morphologies, sizes, and numbers could be estimated. All RPP patients included in this study harbored oral treponemes that represent either novel species, e.g.,Treponema maltophilum, or uncultivable phylotypes. Therefore, it is necessary to include these organisms in etiologic considerations and to strengthen efforts to cultivate these as yet uncultivable treponemes.

scholarly journals Synthesis of Copper Nanoparticles Stabilized with Organic Ligands and Their Antimicrobial Properties

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2846
Author(s):  
Noemi Jardón-Maximino ◽  
Marissa Pérez-Alvarez ◽  
Gregorio Cadenas-Pliego ◽  
Luis E. Lugo-Uribe ◽  
Christian Cabello-Alvarado ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Synthesis Method ◽  
Antimicrobial Properties ◽  
Stabilizing Agents ◽  
Copper Sulfate Pentahydrate ◽  
The Stability ◽  
High Yields ◽  
Zeta Potential Analysis

In this work, we report the synthesis of copper nanoparticles (Cu NPs), employing the chemical reduction method in an aqueous medium. We used copper sulfate pentahydrate (CuSO4·5H2O) as a metallic precursor; polyethylenimine (PEI), allylamine (AAM), and 4-aminobutyric acid (AABT) as stabilizing agents; and hydrated hydrazine as a reducing agent. The characterization of the obtained nanoparticles consisted of X-ray, TEM, FTIR, and TGA analyses. Through these techniques, it was possible to detect the presence of the used stabilizing agents on the surface of the NPs. Finally, a zeta potential analysis was performed to differentiate the stability of the nanoparticles with a different type of stabilizing agent, from which it was determined that the most stable nanoparticles were the Cu NPs synthesized in the presence of the PEI/AAM mixture. The antimicrobial activity of Cu/PEI/AABT toward P. aeruginosa and S. aureus bacteria was high, inhibiting both bacteria with low contact times and copper concentrations of 50–200 ppm. The synthesis method allowed us to obtain Cu NPs free of oxides, stable to oxidation, and with high yields. The newly functionalized Cu NPs are potential candidates for antimicrobial applications.

scholarly journals In-situ STEM study on the morphological evolution of copper-based nanoparticles during high-temperature redox reactions

Nanoscale ◽  
2021 ◽  
Author(s):  
Sharmin Afroz Sharna ◽  
Mounib Bahri ◽  
Corinne Bouillet ◽  
Virgile Rouchon ◽  
Arnold Lambert ◽  
...  
Keyword(s):  
High Temperature ◽  
Copper Nanoparticles ◽  
Redox Reactions ◽  
Morphological Evolution ◽  
Industrial Applications ◽  
Fundamental Understanding

Despite the broad relevance of copper nanoparticles in industrial applications, the fundamental understanding of oxidation and reduction of copper at the nanoscale is still a matter of debate and remains...

Characterization of cotton fabric nanocomposites with in situ generated copper nanoparticles for antimicrobial applications

2018 ◽  
Vol 48 (7) ◽  
pp. 574-581 ◽  
Author(s):  
Sivaranjana Paramasivan ◽  
Nagarajan E.R. ◽  
Rajini Nagarajan ◽  
Varada Rajulu Anumakonda ◽  
Hariram N.
Keyword(s):  
Cotton Fabric ◽  
Copper Nanoparticles
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