scholarly journals Red-Emitting Hybrid Based on Eu3+-dbm Complex Anchored on Silica Nanoparticles Surface by Carboxylic Acid for Biomarker Application

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5494
Author(s):  
João A. O. Santos ◽  
Alessandra M. G. Mutti ◽  
Airton G. Bispo-Jr ◽  
Ana M. Pires ◽  
Sergio A. M. Lima
Keyword(s):  
Carboxylic Acid ◽  
Aqueous Suspension ◽  
Aqueous Media ◽  
Particle Morphology ◽  
Hybrid Structure ◽  
Hierarchical Organization ◽  
Stable Suspension ◽  
Carboxylate Groups ◽  
Red Luminescence ◽  
Average Size

Luminescent organic-inorganic hybrids containing lanthanides (Ln3+) have been prominent for applications such as luminescent bio-probes in biological assays. In this sense, a luminescent hybrid based on dense silica (SiO2) nanospheres decorated with Eu3+ β–diketonate complexes using dibenzoylmethane (Hdbm) as a luminescent antenna was developed by using a hierarchical organization in four steps: (i) anchoring of 3-aminopropyltriethoxysilane (APTES) organosilane on the SiO2 surface, (ii) formation of a carboxylic acid ligand, (iii) coordination of Eu3+ to the carboxylate groups and (iv) coordination of dbm− to Eu3+. The hybrid structure was elucidated through the correlation of thermogravimetry, silicon nuclear magnetic resonance and photoluminescence. Results indicate that the carboxylic acid-Eu3+-dbm hybrid was formed on the surface of the particles with no detectable changes on their size or shape after all the four steps (average size of 32 ± 7 nm). A surface charge of −27.8 mV was achieved for the hybrid, assuring a stable suspension in aqueous media. The Eu3+ complex provides intense red luminescence, characteristic of Eu3+5D0→7FJ electronic transitions, with an intrinsic emission quantum yield of 38%, even in an aqueous suspension. Therefore, the correlation of luminescence, structure, particle morphology and fluorescence microscopy images make the hybrid promising for application in bioimaging.

scholarly journals Microscopic Image Segmentation and Morphological Characterization of Novel Chitosan/Silica Nanoparticle/Nisin Films Using Antimicrobial Technique for Blueberry Preservation

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 303
Author(s):  
Rokayya Sami ◽  
Schahrazad Soltane ◽  
Mahmoud Helal
Keyword(s):  
Ph Value ◽  
Silica Nanoparticle ◽  
Morphological Characterization ◽  
Aerobic Bacteria ◽  
Nano Materials ◽  
Elongation At Break ◽  
Stable Suspension ◽  
Average Size ◽  
Material Ductility

In the current work, the characterization of novel chitosan/silica nanoparticle/nisin films with the addition of nisin as an antimicrobial technique for blueberry preservation during storage is investigated. Chitosan/Silica Nanoparticle/N (CH-SN-N) films presented a stable suspension as the surface loads (45.9 mV) and the distribution was considered broad (0.62). The result shows that the pH value was increased gradually with the addition of nisin to 4.12, while the turbidity was the highest at 0.39. The content of the insoluble matter and contact angle were the highest for the Chitosan/Silica Nanoparticle (CH-SN) film at 5.68%. The use of nano-materials in chitosan films decreased the material ductility, reduced the tensile strength and elongation-at-break of the membrane. The coated blueberries with Chitosan/Silica Nanoparticle/N films reported the lowest microbial contamination counts at 2.82 log CFU/g followed by Chitosan/Silica Nanoparticle at 3.73 and 3.58 log CFU/g for the aerobic bacteria, molds, and yeasts population, respectively. It was observed that (CH) film extracted 94 regions with an average size of 449.10, at the same time (CH-SN) film extracted 169 regions with an average size of 130.53. The (CH-SN-N) film presented the best result at 5.19%. It could be observed that the size of the total region of the fruit for the (CH) case was the smallest (1663 pixels), which implied that the fruit lost moisture content. As a conclusion, (CH-SN-N) film is recommended for blueberry preservation to prolong the shelf-life during storage.

Diameter-Selective Solubilization of Carbon Nanotubes by Lipid Micelles

2008 ◽  
Vol 8 (1) ◽  
pp. 420-423 ◽  
Author(s):  
Dimitrios Tasis ◽  
Konstantinos Papagelis ◽  
Dionysios Douroumis ◽  
James R. Smith ◽  
Nikolaos Bouropoulos ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanostructures ◽  
Aqueous Suspension ◽  
Aqueous Media ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
One Step ◽  
The One ◽  
Walled Carbon Nanotubes

The one-step dispersion of HiPco single-walled carbon nanotubes in aqueous media with the use of a synthetic lyso-phosphatidylcholine was studied. Solubilization occurs through wrapping of lipid molecules around the circumference of the tubes, yielding lipid monolayers on the graphitic sidewalls as evidenced by atomic force microscopy imaging and dynamic light scattering measurements. Raman spectroscopy showed that the dispersion and centrifugation process leads to an effective enrichment of the stable aqueous suspension in carbon nanostructures with smaller diameters.

scholarly journals Europium-Doped Ceria Nanocrystals as Nanozyme Fluorescent Probes for Biosensing

2021 ◽  
Vol 5 (1) ◽  
pp. 53
Author(s):  
Ali Othman ◽  
Akhtar Hayat ◽  
Silvana Andreescu
Keyword(s):  
Fluorescent Dyes ◽  
Aqueous Media ◽  
Doped Ceria ◽  
New Wave ◽  
Lactate Oxidase ◽  
Fluorescence Sensing ◽  
Combined Use ◽  
Direct Fluorescence ◽  
Average Size

Molecular nanoprobes with intrinsic enzyme-like activity represent a new wave of technology for rapid and sensitive detection of molecular targets. This work reports synthesis and characterization of novel and well-dispersed europium-doped ceria nanocrystals (EuCe NCs) with self-integrated catalytic and fluorescence sensing functions. The NCs have an average size of ∼5 nm and exhibit bright and stable fluorescence for more than 6 months in aqueous media. Their dual cooperative function as both a catalyst and fluorescent probe was explored to develop a universally applicable fluorescence-based biosensing method to monitor enzyme reactions and quantitatively measure clinically relevant molecules. Sensing capabilities are demonstrated for detection of H2O2, glucose/glucose oxidase, lactate/lactate oxidase, phosphatase activity, and the catecholamine neurotransmitter, dopamine. Results indicate that EuCe NCs not only provide high enzyme-mimetic activity, but also impart direct fluorescence sensing ability enabling all-in-one recognition, catalytic amplification, and the detection of biomolecular targets. The EuCe nanozyme offers a stable alternative to the more complex systems based on the combined use of natural enzymes and fluorescent dyes. The high stability and fluorescence detection capabilities demonstrate that EuCe NCs have the potential to be used as a generic platform in chemical and biological sensing and bioimaging applications.

Dry Transfer Inoculation of Low-Moisture Spices Containing Antimicrobial Compounds

2017 ◽  
Vol 80 (2) ◽  
pp. 338-344 ◽  
Author(s):  
Ian M. Hildebrandt ◽  
Chuxuan Hu ◽  
Elizabeth M. Grasso-Kelley ◽  
Peiran Ye ◽  
Nathan M. Anderson ◽  
...  
Keyword(s):  
Aqueous Suspension ◽  
Aqueous Media ◽  
Food Product ◽  
Black Pepper ◽  
Antimicrobial Compounds ◽  
High Concentration ◽  
Silica Beads ◽  
Ginger Powder ◽  
Inoculation Procedure ◽  
Transfer Method

ABSTRACT Inoculation of a food product for use in subsequent validation studies typically makes use of a high concentration cocktail of microorganisms suspended in aqueous media. However, this inoculation method may prove difficult particularly when the food product is a low-moisture food containing antimicrobial compounds, such as some dried spices. In this study, a dry transfer method for inoculation of clove powder, oregano leaves, ginger powder, and ground black pepper with a five-serovar cocktail of Salmonella was developed and compared with a traditional aqueous inoculation procedure. Spices were inoculated at three levels, 10, 8, and 6 log CFU/g, by using both an aqueous suspension of Salmonella and a dry transfer of Salmonella from previously inoculated silica beads. At the highest inoculation level, the dry transfer method resulted in a significantly higher microbial load (P < 0.05) for ground cloves and oregano, but not for ginger and ground black pepper. At the intermediate inoculation level, differences were apparent only for ginger and black pepper. Inoculation levels of 6 log CFU/g resulted in recoveries below detection limits for both methods of inoculation. Additional examination on the survival of Salmonella on silica beads after inoculation and in clove powder after dry transfer from silica beads showed linear rates of decline, with a rate of −0.011 log CFU/g/day for beads and −0.015 log CFU/g/day for clove powder. The results suggest that dry transfer of Salmonella via inoculated silica beads is a viable alternative when traditional aqueous inoculation is not feasible.

Production of In, Au, and Pt nanoparticles by discharge plasmas in water for assessment of their bio-compatibility and toxicity

MRS Advances ◽  
2016 ◽  
Vol 1 (18) ◽  
pp. 1301-1306
Author(s):  
Takaaki Amano ◽  
Thapanut Sarinont ◽  
Kazunori Koga ◽  
Miyuki Hirata ◽  
Akiyo Tanaka ◽  
...  
Keyword(s):  
Platinum Nanoparticles ◽  
Aqueous Suspension ◽  
Pt Nanoparticles ◽  
Indium Content ◽  
Intratracheal Administration ◽  
Discharge Plasmas ◽  
Preliminary Examination ◽  
Indium Nanoparticles ◽  
Average Size ◽  
Bio Compatibility

ABSTRACTNanoparticles have great potential for biomedical applications such as early detection, accurate diagnosis, and personalized treatment of cancer. Assessment of bio-compatibility and toxicity of nanoparticles body is an emerging topic for these applications. To study kinetics of nanoparticles in body, we synthesized indium, gold and platinum nanoparticles in aqueous suspension using pulsed electrical discharge plasmas in water. The average size of synthesized primary nanoparticles for indium, gold, and platinum are 6.2 nm, 6.7 nm, and 5.4 nm, whereas the average size of secondary nanoparticles for indium, gold, and platinum are 315 nm, 72.3 nm, and 151 nm, respectively. Synthesized indium nanoparticles are transported from subcutaneous to serum and brain. The indium content in serum for the synthesized nanoparticles is much higher than that for the In2O3 nanoparticles of 150 nm in primary size. For gold and platinum nanoparticles, preliminary examination of intratracheal administration revealed that administration of synthesized nanoparticles with 10 mg/kg BW (body weight) may cause bleedings and/or emphysema in lung.

scholarly journals Synthesis and self-assembly of zinc oxide nanoparticles with septahedral morphology

2008 ◽  
Vol 23 (2) ◽  
pp. 529-535 ◽  
Author(s):  
Nelson S. Bell ◽  
David R. Tallant ◽  
Rebecca Raymond ◽  
Timothy J. Boyle
Keyword(s):  
Carboxylic Acid ◽  
Self Assembly ◽  
Ostwald Ripening ◽  
High Specificity ◽  
Living Cells ◽  
Particle Assembly ◽  
Carboxylate Groups ◽  
Biological Labeling ◽  
Habit Planes ◽  
Surface Facets

The formation of 10-nm ZnO nanopyramids using a simple synthetic route has been isolated from the reaction of Zn(OAc)2·2H2O in 1,4-butanediol followed by ripening at 90 °C. This was accomplished by establishing control over the Ostwald ripening process through the use of a carboxylic acid specific adsorbate. Using a variety of analytical methods, it is proposed that the carboxylate groups in the acetate precursor stabilize the {101} habit planes, creating septahedral shapes or nanopyramids. Particle assembly into crystallographically oriented dimers was observed with high specificity, and the association mechanism is suggested to relate to the crystal polarity and the variation in specific adsorption of the carboxylic acid to the surface facets. These materials are a candidate for biological labeling applications in living cells.

Anhydrous Chromium(III) Carboxylates: Reactions of CrO3 with Carboxylic Acid Anhydrides

1983 ◽  
Vol 38 (1) ◽  
pp. 42-44 ◽  
Author(s):  
Ramesh Kapoor ◽  
Ramneek Sharma
Keyword(s):  
Magnetic Susceptibility ◽  
Carboxylic Acid ◽  
Nmr Spectra ◽  
Octahedral Geometry ◽  
H Nmr ◽  
Chromium Vi ◽  
Carboxylate Groups ◽  
Different Types ◽  
Pure Chromium ◽  
Acid Anhydrides

Abstract Chromium(VI) oxide reacts with excess of carboxylic acid anhydrides [(RCO)2O where R = CH3, C2H5, n-C3H7 and CHCl2] to give pure chromium(III) carboxylates. Their IR and 1H NMR spectra suggest the presence of two different types of carboxylate groups. Magnetic susceptibility and absorption spectra favour an octahedral geometry around Cr.

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