scholarly journals АССМОТРЕНИЕ ВЛИЯНИЯ САМОАГРЕГИРОВАНИЯ В НАНОРАЗМЕРНЫХ КЛАСТЕРАХ CDS

2021 ◽  
Vol 78 (3) ◽  
pp. 51-60
Author(s):  
A.M. Assilbekova ◽  
◽  
A.A. Aldongarov ◽  
I.S. Irgibaeva ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Dipole Moment ◽  
Cadmium Sulfide ◽  
Density Functional ◽  
Electronic Absorption Spectra ◽  
Semiconductor Nanocrystals ◽  
Emission Spectra ◽  
Cds Nanoparticles ◽  
Trap States ◽  
Narrow Emission

Quantum dots, such as cadmium sulfide (CdS), are semiconductor nanocrystals that possess unique optical properties, including wide­range excitation, size­tunable narrow emission spectra and high pho­tostability. The size and composition of quantum dots can be varied to obtain the desired emission prop­erties and make them suitable for various optical and biomedical applications. In this article, the effect of self­aggregation on the electronic absorption spectra and on the dipole moment in CdS nanoparticles is considered using computer modeling methods based on the density functional tight­binding (DFTB). The object of the study is four CdS structures and two models of an aggregated dimer for each cluster. The construction of dimers of cadmium sulfide clusters showed that a higher level of passivation can be achieved in comparison with the initial monomers. In this case, the construction of dimers should occur along the direction of the dipole moment of the monomer in order to minimize it. Therefore, it can be assumed that the dipole moment plays a key role in the formation of trap states in nanosized clusters of cadmium sulfide, and the problem of passivation is reduced to minimizing the dipole moment.

scholarly journals CdSe Quantum Dots in Human Models Derived from ALS Patients: Characterization, Nuclear Penetration Studies and Multiplexing

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 671
Author(s):  
Carlota Tosat-Bitrián ◽  
Alicia Avis-Bodas ◽  
Gracia Porras ◽  
Daniel Borrego-Hernández ◽  
Alberto García-Redondo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Mechanisms ◽  
Emission Spectra ◽  
Molecular Profiling ◽  
Proper Function ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Narrow Emission

CdSe quantum dots (QDs) are valuable tools for deciphering molecular mechanisms in cells. Their conjugation with antibodies offers a unique staining source with optimal characteristics, including increased photostability and narrow emission spectra, allowing for improved multiplexing capabilities using a single excitation source. In combination with pathology models derived from patients, they have great potential to contribute to quantitative molecular profiling and promote personalized medicine. However, the commercial availability of diverse CdSe QDs is still limited and characterization techniques must be performed to these materials or the conjugates developed in the lab to assure a proper function and reproducibility. Furthermore, while there is significant data of QDs experiments in cell lines, the literature with primary human cells is scarce, and QD behavior in these systems may be different. Rigorous characterization data of commercially available QDs and their conjugates with biomolecules of interest is needed in order to establish their potential for target labelling and expand their use among research labs. Here we compare the characterization and labelling performance of different QD conjugates in SH-SY5Y cell line, fibroblasts and immortalized lymphocytes derived from amyotrophic lateral sclerosis patients.

scholarly journals D-Glucosamine Conjugation Accelerates the Labeling Efficiency of Quantum Dots in Osteoblastic Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Kazunari Igawa ◽  
Ming-Fang Xie ◽  
Hideki Ohba ◽  
Shizuka Yamada ◽  
Yoshihiko Hayashi
Keyword(s):  
Quantum Dots ◽  
Emission Spectra ◽  
Osteoblastic Cells ◽  
Core Size ◽  
Fluorescent Staining ◽  
Broad Absorption ◽  
Dramatic Decrease ◽  
High Fluorescence Intensity ◽  
High Fluorescence ◽  
Narrow Emission

Quantum dots (QDs) are useful imaging tools in the medical and biological fields due to their optical properties, such as a high fluorescence intensity, remarkable resistance to photobleaching, broad absorption spectra, and narrow emission spectra. This is the first study to investigate the uptake of carboxylated QDs conjugated with D-glucosamine (core size: approximately 3 nm, final modified size: 20–30 nm) into cultured osteoblastic cells. The QDs attached to the cell surface and were transported into the cytoplasm within approximately three hours of culture, whose process was clearly demonstrated using specific fluorescent staining of the cell membrane. Although the intranuclear distribution was not observed, a dramatic decrease in the transfer of quantum dots into the cytoplasm was recognized after approximately seven days of culture. Other interesting phenomena include the escape of the quantum dots from lysosomes in the cytoplasm, as confirmed by the merging of both QD fluorescence and specific fluorescent staining of lysosomes in the cytoplasm. These findings suggest that D-glucosamine conjugation enhances proton absorption in acid organelles and promotes the lysosomal escape of QDs.

SYNTHESIS OF NANOCRYSTALLINE CdS QUANTUM DOTS VIA PARAFFIN LIQUID AS SOLVENT AND OLEIC ACID AS THE REACTING MEDIA

2012 ◽  
Vol 11 (06) ◽  
pp. 1240038 ◽  
Author(s):  
WENJIANG LI ◽  
MINGRUI WANG ◽  
FEI XIE ◽  
SHA ZHU ◽  
YUE ZHAO
Keyword(s):  
Quantum Dots ◽  
Oleic Acid ◽  
Semiconductor Nanocrystals ◽  
Emission Spectra ◽  
Medical Diagnostics ◽  
X Ray Diffraction ◽  
Hrtem Observation ◽  
Average Grain Size ◽  
Cds Qds ◽  
Paraffin Liquid

Fluorescent semiconductor nanocrystals have been widely used as fluorescent materials in chemical sensors, biotechnology, medical diagnostics, biological imaging and many other fields. Compared to the conventional organic fluorophores, the inorganic quantum dots (QDs) have many advantages, including broad absorption spectra, narrow emission spectra, good photostability and long fluorescent lifetime after excitation. Here, the high quality CdS QDs were synthesized directly from sulfur and CdO using the paraffin liquid as solvent and the oleic acid as the reacting media. The synthesized CdS QDs with a zinc blende (cubic) crystal structure were proved by X-ray diffraction. HRTEM observation revealed that the CdS QDs were uniform and the average grain size was about 4 nm. The optical properties of the CdS QDs were characterized by using photoluminescence (PL) spectrophotometer and Ultraviolet-visible (UV-Vis) absorption spectrophotometer. The formation mechanism of CdS QDs in the paraffin liquid and oleic acid system was proposed.

scholarly journals Anticancer and Antibacterial Activity of Cadmium Sulfide Nanoparticles by Aspergillus niger

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Mohammed S. Alsaggaf ◽  
Ashraf F. Elbaz ◽  
Sherin El Badawy- ◽  
Shaaban H. Moussa
Keyword(s):  
Antimicrobial Activity ◽  
Aspergillus Niger ◽  
Cadmium Sulfide ◽  
Emission Spectra ◽  
Spherical Particles ◽  
Cds Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli ◽  
Cadmium Sulfide Nanoparticles

Cadmium-tolerant (6 mM) Aspergillus niger (RCMB 002002) biomass was challenged with aqueous cadmium chloride (1 mM) followed by sodium sulfide (9 mM) at 37°C for 96 h under shaking conditions (200 rpm), resulting in the formation of highly stable polydispersed cadmium sulfide nanoparticles (CdSNPs). Scanning electron microscopy revealed the presence of spherical particles measuring approximately 5 nm. A light scattering detector (LSD) showed that 100% of the CSNPs measure from 2.7 to 7.5 nm. Structural analyses by both powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the presence of cubic CdS nanoparticles (CdSNPs) capped with fungal proteins. These CdSNPs showed emission spectra with a broad fluorescence peak at 420 nm and UV absorption onset at 430 nm that shifted to 445 nm after three months of incubation. The CdSNPs showed antimicrobial activity against E. coli, Pseudomonas vulgaris, Staphylococcus aureus, and Bacillus subtilis, and no antimicrobial activity was detected against Candida albicans. The biosynthesized CdSNPs have cytotoxic activity, with 50% inhibitory concentrations (IC50) of 190 μg mL-1 against MCF7, 246 μg mL-1 against PC3, and 149 μg mL-1 against A549 cell lines.

Imaging Takes a Quantum Leap

Physiology ◽  
2004 ◽  
Vol 19 (6) ◽  
pp. 322-325 ◽  
Author(s):  
Diane S. Lidke ◽  
Donna J. Arndt-Jovin
Keyword(s):  
Quantum Dots ◽  
Surface Chemistry ◽  
Fluorescence Imaging ◽  
Emission Spectra ◽  
Quantum Leap ◽  
In Vivo Fluorescence Imaging ◽  
Biomolecular Conjugation ◽  
Narrow Emission

Semiconducting nanocrystals, or quantum dots (QDs), have emerged as a new tool in physiological imaging, combining high brilliance, photostability, broad excitation but very narrow emission spectra, and surface chemistry compatible with biomolecular conjugation. In this review, we demonstrate the power of QDs in diverse applications, including long-term in vivo fluorescence imaging.

Communication: Photoinduced Carbon Dioxide Binding with Surface-Functionalized Silicon Quantum Dots

2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
Cristián Gabriel Sánchez ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Carbon Dioxide ◽  
Quantum Dots ◽  
Atmospheric Carbon Dioxide ◽  
Density Functional ◽  
Tight Binding ◽  
Carbon Dioxide Concentration ◽  
Research Area ◽  
Silicon Quantum Dots ◽  
Dependent Model ◽  
Photoinduced Charge

<div> <div> <div> <p>Nowadays, the search of efficient methods able to reduce the high atmospheric carbon dioxide concentration has turned into a very dynamic research area. Several environmental problems have been closely associated with the high atmospheric level of this greenhouse gas. Here, a novel system based on the use of surface-functionalized silicon quantum dots (sf -SiQDs) is theoretically proposed as a versatile device to bind carbon dioxide. Within this approach, carbon dioxide trapping is modulated by a photoinduced charge redistribution between the capping molecule and the silicon quantum dots (SiQDs). Chemical and electronic properties of the proposed SiQDs have been studied with Density Functional Theory (DFT) and Density Functional Tight-Binding (DFTB) approach along with a Time-Dependent model based on the DFTB (TD-DFTB) framework. To the best of our knowledge, this is the first report that proposes and explores the potential application of a versatile and friendly device based on the use of sf -SiQDs for photochemically activated carbon dioxide fixation. </p> </div> </div> </div>

scholarly journals Photoluminescent Coordination Polymers Based on Group 12 Metals and 1H-Indazole-6-Carboxylic Acid

Inorganics ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 20
Author(s):  
Antonio A. García-Valdivia ◽  
Estitxu Echenique-Errandonea ◽  
Gloria B. Ramírez-Rodríguez ◽  
José M. Delgado-López ◽  
Belén Fernández ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Coordination Polymers ◽  
Density Functional ◽  
Free Ligand ◽  
Emission Spectra ◽  
Point Of View ◽  
Theoretical Point ◽  
Fourier Transformed Infrared Spectroscopy ◽  
3D Network ◽  
The Stability

Two new coordination polymers (CPs) based on Zn(II) and Cd(II) and 1H-indazole-6-carboxylic acid (H2L) of general formulae [Zn(L)(H2O)]n (1) and [Cd2(HL)4]n (2) have been synthesized and fully characterized by elemental analyses, Fourier transformed infrared spectroscopy and single crystal X-ray diffraction. The results indicate that compound 1 possesses double chains in its structure whereas 2 exhibits a 3D network. The intermolecular interactions, including hydrogen bonds, C–H···π and π···π stacking interactions, stabilize both crystal structures. Photoluminescence (PL) properties have shown that compounds 1 and 2 present similar emission spectra compared to the free-ligand. The emission spectra are also studied from the theoretical point of view by means of time-dependent density-functional theory (TD-DFT) calculations to confirm that ligand-centred π-π* electronic transitions govern emission of compound 1 and 2. Finally, the PL properties are also studied in aqueous solution to explore the stability and emission capacity of the compounds.

scholarly journals Transparent Ion-Exchange Membrane Exhibiting Intense Emission under a Specific pH Condition Based on Polypyridyl Ruthenium(II) Complex with Two Imidazophenanthroline Groups

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 400
Author(s):  
Hajime Kamebuchi ◽  
Satoshi Tamaki ◽  
Atsushi Okazawa ◽  
Norimichi Kojima
Keyword(s):  
Ion Exchange ◽  
Emission Intensity ◽  
Density Functional ◽  
Emission Spectra ◽  
Density Functional Theory Calculations ◽  
Ion Exchange Membrane ◽  
Quantum Yields ◽  
Relative Emission Intensity ◽  
Nafion Film ◽  
Exchange Membrane

The development and the photophysical behavior of a transparent ion-exchange membrane based on a pH-sensitive polypyridyl ruthenium(II) complex, [(bpy)2RuII(H2bpib)RuII(bpy)2](ClO4)4 (bpy = 2,2′-bipyridine, H2bpib = 1,4-bis([1,10]phenanthroline[5,6-d]-imidazol-2-yl)benzene), are experimentally and theoretically reported. The emission spectra of [(bpy)2RuII(H2bpib)RuII(bpy)2]@Nafion film were observed between pH 2 and pH 11 and showed the highest relative emission intensity at pH 5 (λmaxem = 594.4 nm). The relative emission intensity of the film significantly decreased down to 75% at pH 2 and 11 compared to that of pH 5. The quantum yields (Φ) and lifetimes (τ) showed similar correlations with respect to pH, Φ = 0.13 and τ = 1237 ns at pH 5, and Φ = 0.087 and τ = 1014 ns and Φ = 0.069 and τ = 954 ns at pH 2 and pH 11, respectively. These photophysical data are overall considerably superior to those of the solution, with the radiative- (kr) and non-radiative rate constants (knr) at pH 5 estimated to be kr = 1.06 × 105 s−1 and knr = 7.03 × 105 s−1. Density functional theory calculations suggested the contribution of ligand-to-ligand- and intraligand charge transfer to the imidazolium moiety in Ru-H3bpib species, implying that the positive charge on the H3bpib ligand works as a quencher. The Ru-Hbpib species seems to enhance non-radiative deactivation by reducing the energy of the upper-lying metal-centered excited state. These would be responsible for the pH-dependent “off-on-off” emission behavior.

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