scholarly journals Quantum Dots—Assisted 2D Fluorescence for Pattern Based Sensing of Amino Acids, Oligopeptides and Neurotransmitters

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3655 ◽  
Author(s):  
Marcin Zabadaj ◽  
Patrycja Ciosek-Skibińska
Keyword(s):  
Amino Acids ◽  
Quantum Dots ◽  
Emission Spectra ◽  
Specific Interactions ◽  
High Quantum Yield ◽  
Huge Amount ◽  
Broad Absorption ◽  
Amount Of Information ◽  
Decay Times ◽  
Proof Of Principle

Quantum dots (QDs) are very attractive nanomaterials for analytical chemistry, due to high photostability, large surface area featuring numerous ways of bioconjugation with biomolecules, usually high quantum yield and long decay times. Their broad absorption spectra and narrow, sharp emission spectra of size-tunable fluorescence make them ideal tools for pattern-based sensing. However, almost always they are applied for specific sensing with zero-dimensional (0D) signal reporting (only peak heights or peak shifts are considered), without taking advantage of greater amount of information hidden in 1D signal (emission spectra), or huge amount of information hidden in 2D fluorescence maps (Excitation-Emission Matrixes, EEMs). Therefore, in this work we propose opposite strategy—non-specific interactions of QDs, which are usually avoided and regarded as their disadvantage, were exploited here for 2D fluorescence fingerprinting. Analyte-specific multivariate fluorescence response of QDs is decoded with the use of Partial Least Squares—Discriminant Analysis. Even though only one type of QDs is studied, the proposed pattern-based method enables to obtain satisfactory accuracy for all studied compounds—various neurotransmitters, amino-acids and oligopeptides. This is a proof of principle of the possibility of the identification of various bioanalytes by such fluorescence fingerprinting with the use of QDs.

Photoluminescence and Scintillation Properties of Pb2+ Based Quantum Dots in CsCI Host Crystal

1994 ◽  
Vol 348 ◽  
Author(s):  
M. Nikl ◽  
K. Nitsch ◽  
I. Dafinei ◽  
P. Lecoq ◽  
G.P. Pazzi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Steady State ◽  
Room Temperature ◽  
Emission Spectra ◽  
Emission Peak ◽  
Kinetic Properties ◽  
Host Crystal ◽  
Exponential Behavior ◽  
Decay Times ◽  
Single Exponential

ABSTRACTThe spectral and kinetic properties of photoluminescence of Pb2+ aggregated phase in CsC1 host, together with scintillation characteristics of CsCI:Pb crystals, are reported in the 10 - 300 K temperature range. Absorption, steady-state excitation and emission spectra of Pb2+ phase in CsCI host are similar to those of CsPbCl3 bulk crystal (emission peak at 419 nm at 10 K). The decay of the 421 nm luminescence of the Pb2+ phase in CsCl shows single exponential behavior with extremely short decay time of 40 ps at 421 nm and 10 K,which is considerably shorter than the decay times found in the decay of CsPbCl3 bulk emission (0.45, 2.8 and 12 ns at 418 nm and 10 K). In the scintillation decay of CsCI:Pb, two components with 0.95-1 ns and 2-3 ns decay times were found and no slower component is present at room temperature.

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.

scholarly journals The bright future: Imaging dynamic cellular events with quantum dots

2010 ◽  
Vol 32 (3) ◽  
pp. 12-17 ◽  
Author(s):  
Andrew M. Smith ◽  
Mary M. Wen ◽  
Shuming Nie
Keyword(s):  
Quantum Dots ◽  
Light Emission ◽  
Emission Spectra ◽  
Semiconductor Quantum Dots ◽  
Broad Absorption ◽  
Light Emitting ◽  
Simultaneous Excitation ◽  
New Class ◽  
Cellular Events ◽  
Optical And Electronic Properties

Semiconductor quantum dots (QDs) are tiny light-emitting particles that have emerged as a new class of fluorescent labels for biology and medicine. Compared with traditional fluorescent probes, QDs have unique optical and electronic properties such as size-tuneable light emission, narrow and symmetric emission spectra, and broad absorption spectra that enable the simultaneous excitation of multiple fluorescence colours.

ELECTRON STRUCTURE INVESTIGATIONS OF InGaP/GaAs(100) HETEROSTRUCTURES WITH InP QUANTUM DOTS

2007 ◽  
Vol 06 (03n04) ◽  
pp. 215-219
Author(s):  
E. P. DOMASHEVSKAYA ◽  
V. A. TEREKHOV ◽  
V. M. KASHKAROV ◽  
S. YU. TURISHCHEV ◽  
S. L. MOLODTSOV ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Partial Density ◽  
Edge Structure ◽  
X Ray ◽  
Metal Organic ◽  
Structure Investigations ◽  
First Time ◽  
Inp Quantum Dots

Ultrasoft X-ray emission spectra (USXES) and X-ray absorption near-edge structure (XANES) spectra with the use of synchrotron radiation in the range of P L2,3-edges were obtained for the first time for nanostructures with InP quantum dots grown on GaAs 〈100〉 substrates by vapor-phase epitaxy from metal–organic compounds. These spectra represent local partial density of states in the valence and conduction bands. The additional XANES peak is detected; its intensity depends on the number of monolayers forming quantum dots. Assumptions are made on the band-to-band origin of luminescence spectra in the studied nanostructures.

scholarly journals Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

2018 ◽  
Vol 9 ◽  
pp. 1544-1549 ◽  
Author(s):  
Margarita A Kurochkina ◽  
Elena A Konshina ◽  
Daria Khmelevskaia
Keyword(s):  
Quantum Dots ◽  
Liquid Crystals ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Dielectric Anisotropy ◽  
Vertical Position ◽  
Decay Times ◽  
Pl Intensity

We have experimentally investigated the effect of the reorientation of a nematic liquid crystal (LC) in an electric field on the photoluminescence (PL) of CdSe/ZnS semiconductor quantum dots (QDs). To the LC with positive dielectric anisotropy, 1 wt % QDs with a core diameter of 5 nm was added. We compared the change of PL intensity and decay times of QDs in LC cells with initially planar or vertically orientated molecules, i.e., in active or passive LC matrices. The PL intensity of the QDs increases four-fold in the active LC matrix and only 1.6-fold in the passive LC matrix without reorientation of the LC molecules. With increasing electric field strength, the quenching of QDs luminescence occurred in the active LC matrix, while the PL intensity did not change in the passive LC matrix. The change in the decay time with increasing electric field strength was similar to the behavior of the PL intensity. The observed buildup in the QDs luminescence can be associated with the transfer of energy from LC molecules to QDs. In a confocal microscope, we observed the increase of particle size and the redistribution of particles in the active LC matrix with the change of the electric field strength. At the same time, no significant changes occurred in the passive LC matrix. With the reorientation of LC molecules from the planar in vertical position in the LC active matrix, quenching of QD luminescence and an increase of the ion current took place simultaneously. The obtained results are interesting for controlling the PL intensity of semiconductor QDs in liquid crystals by the application of electric fields.

scholarly journals Luminescence of SiO2-BaF2:Tb3+, Eu3+ Nano-Glass-Ceramics Made from Sol–Gel Method at Low Temperature

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 259
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Tomasz Goryczka ◽  
Ewa Pietrasik ◽  
Wojciech A. Pisarski
Keyword(s):  
Sol Gel ◽  
Three Dimensional ◽  
Glass Ceramics ◽  
Emission Spectra ◽  
Scanning Calorimetry ◽  
Light Emitting ◽  
Co Doping ◽  
Dsc Measurements ◽  
Decay Times

The synthesis and characterization of multicolor light-emitting nanomaterials based on rare earths (RE3+) are of great importance due to their possible use in optoelectronic devices, such as LEDs or displays. In the present work, oxyfluoride glass-ceramics containing BaF2 nanocrystals co-doped with Tb3+, Eu3+ ions were fabricated from amorphous xerogels at 350 °C. The analysis of the thermal behavior of fabricated xerogels was performed using TG/DSC measurements (thermogravimetry (TG), differential scanning calorimetry (DSC)). The crystallization of BaF2 phase at the nanoscale was confirmed by X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM), and the changes in silicate sol–gel host were determined by attenuated total reflectance infrared (ATR-IR) spectroscopy. The luminescent characterization of prepared sol–gel materials was carried out by excitation and emission spectra along with decay analysis from the 5D4 level of Tb3+. As a result, the visible light according to the electronic transitions of Tb3+ (5D4 → 7FJ (J = 6–3)) and Eu3+ (5D0 → 7FJ (J = 0–4)) was recorded. It was also observed that co-doping with Eu3+ caused the shortening in decay times of the 5D4 state from 1.11 ms to 0.88 ms (for xerogels) and from 6.56 ms to 4.06 ms (for glass-ceramics). Thus, based on lifetime values, the Tb3+/Eu3+ energy transfer (ET) efficiencies were estimated to be almost 21% for xerogels and 38% for nano-glass-ceramics. Therefore, such materials could be successfully predisposed for laser technologies, spectral converters, and three-dimensional displays.

scholarly journals Content profiling and translation scenarios

2016 ◽  
Vol 3 (1) ◽  
pp. 18-37 ◽  
Author(s):  
Sheila Castilho ◽  
Sharon O'Brien
Keyword(s):  
Strategic Management ◽  
End Users ◽  
Huge Amount ◽  
Amount Of Information ◽  
Different Content

Today’s companies are overwhelmed with the need to create a huge amount of content, faster, customized, and for numerous media platforms, in order to support their products. Struggling with managing this amount of information, companies have now realised that the strategic management of multilingual enterprise content has become essential. Strategic management involves profiling content, its uses, its end readers and deciding what should be translated, into which languages, using which translation processes and technology. Profiling enterprise content is necessary in order to maximize the quality of the content and its translation at minimum effort and cost by reducing complexity. By targeting the audience, content could be categorized according to the expectation of the end-users, and so, different translation scenarios can be applied to different content types. This article will discuss the challenges of profiling content within the enterprise, as well as translation scenarios focusing on the decisions that push content in one or another direction.

Quantum dot–polymer conjugates for stable luminescent displays

Nanoscale ◽  
2018 ◽  
Vol 10 (28) ◽  
pp. 13368-13374 ◽  
Author(s):  
Sushant Ghimire ◽  
Anjaly Sivadas ◽  
Ken-ichi Yuyama ◽  
Yuta Takano ◽  
Raju Francis ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Quantum Dot ◽  
Semiconductor Quantum Dots ◽  
Broad Absorption ◽  
Polymer Conjugates ◽  
Absorption Of Light

The broad absorption of light in the UV-Vis-NIR region and the size-based tunable photoluminescence color of semiconductor quantum dots make these tiny crystals one of the most attractive antennae in solar cells and phosphors in electrooptical devices.

Beyond Scientometrics

2019 ◽  
pp. 177-181
Keyword(s):  
Bibliometric Indicators ◽  
Huge Amount ◽  
Scientometric Indicators ◽  
Amount Of Information ◽  
Research Outcomes ◽  
Tools And Techniques ◽  
Alternative Metrics

Numerous websites are currently being used by researchers for sharing and disseminating research, some of which are CiteULike, BibSonomy, Connotea, Mendeley, ResearchGate, etc. For measuring this data, scientists create alternative indicators related to traditional indicators like bibliometric indicators, scientometric indicators. The main purpose of these indicators is that with such huge amount of information available, some specific tools and techniques are required to filter and evaluate the research outcomes. These indicators reveal the societal and unknown impact of the work that traditional metrics are unable to do. The most prominent indicators for this purpose include Altmetrics or article metrics or alternative metrics. The detailed discussion is provided in this chapter.

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