scholarly journals Fluorescence modulation of cadmium sulfide quantum dots by azobenzene photochromic switches

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150692 ◽  
Author(s):  
Hina Javed ◽  
Kalsoom Fatima ◽  
Zareen Akhter ◽  
Muhammad Arif Nadeem ◽  
Muhammad Siddiq ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Mercaptoacetic Acid ◽  
X Ray Diffraction ◽  
Photochromic Compounds ◽  
Lowest Unoccupied Molecular Orbital ◽  
Modified Surface ◽  
Fluorescence Modulation ◽  
Cds Qds ◽  
Surface Modified

We have investigated the attachment of azobenzene photochromic switches on the modified surface of cadmium sulfide (CdS) quantum dots (QDs). The modification of CdS QDs is done by varying the concentration of the capping agent (mercaptoacetic acid) and NH 3 in order to control the size of the QDs. The X-ray diffraction studies revealed that the crystallite size of CdS QDs ranged from 6 to 10 nm. The azobenzene photochromic derivatives bis(4-hydroxybenzene-1-azo)4,4′(1,1′ diphenylmethane) (I) and 4,4′-diazenyldibenzoic acid (II) were synthesized and attached with surface-modified CdS QDs to make fluorophore–photochrome CdS-(I) and CdS-(II) dyad assemblies. Upon UV irradiation, the photochromic compounds (I) and (II) undergo a reversible trans – cis isomerization. The photo-induced trans – cis transformation helps to transfer photo-excited electrons from the conduction band of the CdS QDs to the lowest unoccupied molecular orbital of cis isomer of photochromic compounds (I) and (II). As a result, the fluorescence of CdS-(I) and CdS-(II) dyads is suppressed approximately five times compared to bare CdS QDs. The fluorescence modulation in such systems could help to design luminescent probes for bioimaging applications.

scholarly journals Surface Modified Chitosan with Cadmium Sulfide Quantum Dots as Luminescent Probe for Detection of Silver Ions

2021 ◽  
Vol 33 (5) ◽  
pp. 1025-1030
Author(s):  
Chella Santhosh ◽  
R.S. Ernest Ravindran
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Silver Ions ◽  
Aqueous Solubility ◽  
X Ray Diffraction ◽  
Modified Chitosan ◽  
Transmission Electron ◽  
Cds Qds ◽  
Surface Modified ◽  
Chitosan Composite

In present work, the surface modified cadmium sulfide quantum dots (CdS QDs) was synthesized with chitosan for the detection of silver ions. Chitosan was employed as matrix medium to fabricate CdS QDs, resulting in the formation of novel QDs/chitosan composite. The CdS quantum dots surface coated with chitosan were analyzed using UV-vis spectrophotometer, X-ray diffraction and transmission electron microscope. The chitosan + CdS QDs exhibited high aqueous solubility with better steadiness. By using chitosan + CdS, the silver ions were not only detected but also reduced to nanosize due to the reducing property of chitosan. The mechanism of fluorescence quenching of chitosan + CdS by Ag+ was investigated using photoluminescence spectroscopy.

In situ functionalization of self-assembled dendrimer nanofibers with cadmium sulfide quantum dots through simple ionic-substitution

2016 ◽  
Vol 40 (7) ◽  
pp. 6325-6331 ◽  
Author(s):  
V. Astachov ◽  
M. Garzoni ◽  
A. Danani ◽  
K.-L. Choy ◽  
G. M. Pavan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Simple Approach ◽  
Ionic Substitution ◽  
Cds Qds ◽  
Self Assembled ◽  
Poly Propylene ◽  
In Situ Functionalization

Cadmium sulfide quantum dots (CdS-QDs) can be generated along poly(propylene imine) (PPI) dendrimer-based self-assembled nanofibers through a simple approach based on ionic substitution.

Biochemical and behavioural responses of the marine polychaete Hediste diversicolor to cadmium sulfide quantum dots (CdS QDs): Waterborne and dietary exposure

Chemosphere ◽  
2014 ◽  
Vol 100 ◽  
pp. 63-70 ◽  
Author(s):  
Pierre-Emmanuel Buffet ◽  
Laurence Poirier ◽  
Aurore Zalouk-Vergnoux ◽  
Christelle Lopes ◽  
Jean-Claude Amiard ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Dietary Exposure ◽  
Hediste Diversicolor ◽  
Behavioural Responses ◽  
Marine Polychaete ◽  
Cds Qds

Aged Fingermarks Detection with CdS/PAMAM Nanocomposites

2011 ◽  
Vol 282-283 ◽  
pp. 466-469 ◽  
Author(s):  
Yu Juan Jin ◽  
Yun Jun Luo ◽  
Guo Zhi Xu ◽  
Biao Yang
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Pamam Dendrimers ◽  
Adhesive Tape ◽  
Yellow Luminescence ◽  
Ultraviolet Excitation ◽  
Nano Scale ◽  
Powder Suspension ◽  
Cds Qds

CdS(Cadmium sulfide)/PAMAM(polyamidoamine) Nanocomposites were in-situ prepared taking PAMAM dendrimers as stabilization in water. The prepared solution containing photoluminescent semiconductor CdS QDs(Quantum dots) was utilized for detection of aged fingermarks on adhesive tape strips. The fingermarks were aged for 1 d, 7 d and 30 d in nature light respectively. The results show that the latent aged fingermarks treated with CdS/PAMAM nanocomposites emit yellow luminescence under ultraviolet excitation of 365 nm in the dark. Aged fingermarks were detected successfully with better resolving rate comparing with existing nano-scale commercial TiO2powder suspension.

scholarly journals Comparative Analysis of Proteins Regulated during Cadmium Sulfide Quantum Dots Response in Arabidopsis thaliana Wild Type and Tolerant Mutants

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 615
Author(s):  
Valentina Gallo ◽  
Andrea Zappettini ◽  
Marco Villani ◽  
Nelson Marmiroli ◽  
Marta Marmiroli
Keyword(s):  
Quantum Dots ◽  
Arabidopsis Thaliana ◽  
Comparative Analysis ◽  
Cadmium Sulfide ◽  
Chlorophyll Biosynthesis ◽  
Response To Treatment ◽  
Transcriptional Elongation ◽  
Wild Type ◽  
Abiotic Stress Response ◽  
Cds Qds

In previous work, two independent Arabidopsis thaliana Ac/Ds transposon insertional mutant lines, atnp01 and atnp02, were identified that showed a higher level of tolerance than the wild type (wt) line to cadmium sulfide quantum dots (CdS QDs). The tolerance response was characterized at physiological, genetic and transcriptomic levels. In this work, a comparative analysis was performed on protein extracts from plantlets of the two mutants and of wt, each treated with 80 mg L−1 CdS QDs. A comparative protein analysis was performed by 2D-PAGE, and proteins were characterized by MALDI-TOF/TOF mass spectrometry. Of 250 proteins identified from all three lines, 98 showed significant changes in relative abundance between control and CdS QD-treated plantlets. The wt, atnp01, and atnp02 control-treated pairs respectively showed 61, 31, and 31 proteins with differential expression. The two mutants had a different response to treatment in terms of type and quantity of up- and downregulated proteins. This difference became more striking when compared to wt. A network analysis of the proteins differentially expressed in atnp01 and atnp02 included several of those encoded by putative genes accommodating the transposons, which were responsible for regulation of some proteins identified in this study. These included nifu-like protein 3 (Nfu3), involved in chloroplast assembly, elongator complex 3 (Elo3), involved in transcriptional elongation, magnesium-chelate subunit-2 (Chli2), involved in chlorophyll biosynthesis, and protein phosphatase 2C (PP2C) which mediates abiotic stress response.

The Synthesis of the Folate Acid Quantum Dots and Its Endocytosis in the Hepatoma Cells Mediated by the Folate Receptor

2019 ◽  
Vol 9 (6) ◽  
pp. 770-777
Author(s):  
Xiao-Li Zhu ◽  
Jing-Cheng Tang ◽  
Bing-Jiu Xu
Keyword(s):  
Quantum Dots ◽  
Folic Acid ◽  
Hepg2 Cells ◽  
Folate Receptor ◽  
Synthetic Medium ◽  
Water Soluble ◽  
Mercaptoacetic Acid ◽  
Green Method ◽  
Cds Qds ◽  
Hepg2 Cell Lines

Objectives: To synthesize folate acid conjugated quantum dots (QDs) by a simple and green method and explore endocytosis of the QD-folic acid conjugates (FA-QDs) into hepG2 cells. Methods: CdS QDs were prepared using stearic acid as synthetic medium, and were conjugated with mercaptoacetic acid (MAA) to be water-soluble. Then folic acid moiety was coupled to the surface of the QDs using EDC (1-ethyl-3-(3-dimethylamino propyl)carbodiimide) as a coupling agent. The CdS QDs and FA-QDs were characterized by X-ray spectroscopy (XRD), transmission electron microscopy (TEM), spectro fluorimetry and infrared spectroscopy. Endocytosis of the FA-QDs into hepG2 cells was observed by confocal microscopy and TEM. Results: TEM shows that the CdS QDs and FA-QDs were spherical in shape and had a diameter of 10 nm. Fluorescence spectrum of the QDs also shows their narrow size distribution. Confocal microscopic and TEM results show that FA-QDs were successfully internalized into the hepG2 cells. In addition, confocal results show that when the cells were first be saturated with excess free FA, the endocytosis of the FA-QDs became less, and CdS QDs that were not conjugated with FA were not able to be internalized into the hepG2 cells. Conclusions: The FA-QDs can be synthesized by a simple and green method and be used to successfully target tumor cells: hepG2 cell lines, which was probably mediated by the FA receptor.

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.

Cadmium sulfide quantum dots anchored on reduced graphene oxide for the electrochemical detection of metronidazole

2021 ◽  
Vol 45 (6) ◽  
pp. 3022-3033
Author(s):  
Praveen Kumar Gopi ◽  
Ganesh Kesavan ◽  
Shen-Ming Chen ◽  
Chandan Hunsur Ravikumar
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Cadmium Sulfide ◽  
Reduced Graphene Oxide ◽  
Electrochemical Detection ◽  
Reduced Graphene ◽  
Metal Organic ◽  
Cds Qds

In this research, the metal–organic-based synthesis of cadmium sulfide quantum dots (CdS QDs) was performed.

scholarly journals Corrosion Behavior of Fe/Zr Composite Coating on ZK60 Mg Alloy by Ion Implantation and Deposition

Coatings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 261 ◽  
Author(s):  
Yang Zheng ◽  
Libin Zang ◽  
Yanze Bi ◽  
Yan Li ◽  
Yong Chen
Keyword(s):  
Ion Implantation ◽  
Composite Coating ◽  
Corrosion Behavior ◽  
X Ray Diffraction ◽  
Surface And Interface ◽  
Atomic Force ◽  
Interface Characteristics ◽  
Zk60 Alloy ◽  
Modified Surface ◽  
Surface Modified

The Fe/Zr composite coating was prepared by duplex Fe/Zr ion implantation and deposition to modify the microstructure and corrosion behavior of Mg-5.5 Zn-0.6 Zr (in wt.%, ZK60) alloy. The surface and interface characteristics were investigated using X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM). The results showed that the Fe/Zr composite coating exhibited a bi-layer microstructure of outer Fe-rich layer and inner Zr-rich layer. Multi-phases of α-Fe, ZrO0.35 and Zr6Fe3O were formed on the modified surface. The electrochemical measurements and immersion tests revealed an improvement of corrosion behavior for the surface-modified sample due to the protective effect of Fe/Zr composite coating.

Sign in / Sign up

Export Citation Format

Share Document