Quantum Dots CdSe/ZnS-Loaded Poly(D,L-Lactide-Co-Glycolide) Nanoparticles: Physicochemical Characterization and Application

2006 ◽  
Vol 505-507 ◽  
pp. 667-672 ◽  
Author(s):  
Chih Hui Yang ◽  
Kuo Chin Lin ◽  
Yu Huai Chang ◽  
Yu Cheng Lin
Keyword(s):  
Quantum Dots ◽  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Uv Light ◽  
Physicochemical Characterization ◽  
Plga Nanoparticles ◽  
Optimum Concentration ◽  
Cellular Internalization ◽  
Optimum Concentration Range

This paper described and characterized the quantum dots (QDs) with/without the polymeric PLGA applied in MC3T3E-1 delivery. Neat QDs were treated with various solvents, temperatures, exposure time and concentration to evaluate their stability and efficacy. We found that the intensity degree of fluorescence spectra (QDs) in different solvents follows the order: ether > THF > acetone > chloroform > methanol. Importantly, the QDs become inactive after 8-hr dissolution in the solvents of ether, THF or chloroform. According to this result, acetone and methanol are ideal solvents for QDs. The optimum concentration range of QDs in acetone is 5 to 10 mg/mL. We found that no obvious difference of fluorescence intensity was detected in QDs stored respectively at 4 °C, 24 °C and 44 °C (8-hour). When QDs were exposed to UV light (312 nm) for 2 hr, serious decay of fluorescence intensity was observed. In order to extend the application of QDs in medical areas, we encapsulated them in individual biocompatible poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles for in-vitro imaging of endocytosis in MC3T3E-1 cells. We demonstrated that the polymeric PLGA have the ability to permeate the cells for cellular internalization; the endocytotic activity could be enhanced by the polymeric QDs-encapsulated PLGA.

A Study on UV Filter Chemicals from Annex VII of European Union Directive 76/768/EEC, in the In Vitro 3T3 NRU Phototoxicity Test

1998 ◽  
Vol 26 (5) ◽  
pp. 679-708 ◽  
Author(s):  
Horst Spielmann ◽  
Michael Balls ◽  
Jack Dupuis ◽  
Wolfgang J. W. Pape ◽  
Odile de Silva ◽  
...  
Keyword(s):  
Neutral Red ◽  
Optimum Concentration ◽  
Alternative Methods ◽  
Uv Filter ◽  
Eu Directive ◽  
Optimum Concentration Range ◽  
The Impact ◽  
Positive Results

In 1996, the Scientific Committee on Cosmetology of DGXXIV of the European Commission asked the European Centre for the Validation of Alternative Methods to test eight UV filter chemicals from the 1995 edition of Annex VII of Directive 76/768/EEC in a blind trial in the in vitro 3T3 cell neutral red uptake phototoxicity (3T3 NRU PT) test, which had been scientifically validated between 1992 and 1996. Since all the UV filter chemicals on the positive list of EU Directive 76/768/EEC have been shown not to be phototoxic in vivo in humans under use conditions, only negative effects would be expected in the 3T3 NRU PT test. To balance the number of positive and negative chemicals, ten phototoxic and ten non-phototoxic chemicals were tested under blind conditions in four laboratories. Moreover, to assess the optimum concentration range for testing, information was provided on appropriate solvents and on the solubility of the coded chemicals. In this study, the phototoxic potential of test chemicals was evaluated in a prediction model in which either the Photoirritation Factor (PIF) or the Mean Photo Effect (MPE) were determined. The results obtained with both PIF and MPE were highly reproducible in the four laboratories, and the correlation between in vitro and in vivo data was almost perfect. All the phototoxic test chemicals provided a positive result at concentrations of 1μg/ml, while nine of the ten non-phototoxic chemicals gave clear negative results, even at the highest test concentrations. One of the UV filter chemicals gave positive results in three of the four laboratories only at concentrations greater than 100μg/ml; the other laboratory correctly identified all 20 of the test chemicals. An analysis of the impact that exposure concentrations had on the performance of the test revealed that the optimum concentration range in the 3T3 NRU PT test for determining the phototoxic potential of chemicals is between 0.1μg/ml and 10μg/ml, and that false positive results can be obtained at concentrations greater than 100μg/ml. Therefore, the positive results obtained with some of the UV filter chemicals only at concentrations greater than 100μg/ml do not indicate a phototoxic potential in vivo. When this information was taken into account during calculation of the overall predictivity of the 3T3 NRU PT test in the present study, an almost perfect correlation of in vitro versus in vivo results was obtained (between 95% and 100%), when either PIF or MPE were used to predict the phototoxic potential. The management team and participants therefore conclude that the 3T3 NRU PT test is a valid test for correctly assessing the phototoxic potential of UV filter chemicals, if the defined concentration limits are taken into account.

scholarly journals Establishment of Fluorescence Sensitization Method for Hydroxysafflor Yellow A

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
CAO Haiyan ◽  
QIN Xiude ◽  
LIU Chen ◽  
ZHAO Xinzhe ◽  
MA Yuhui ◽  
...  
Keyword(s):  
Detection Limit ◽  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Pharmacological Effects ◽  
Absorption And Fluorescence Spectra ◽  
Hydroxysafflor Yellow A ◽  
T24 Cells ◽  
Fluorescence Sensitization ◽  
In Cells

As the main active ingredient in Chinese medicine safflower, hydroxysafflor yellow A (HSYA) has multiple pharmacological effects. In the work, the absorption and fluorescence spectra of HSYA under different environmental conditions (such as acidity, temperature, ions, viscosity, and surfactant) were investigated. The fluorescence intensity of HSYA varied greatly with acidity, temperature, viscosity, and surfactant, but was less affected by common cations and anions. Among various surfactants, we found that borax can significantly enhance the HSYA fluorescence intensity, and thus, a borax-HSYA sensitization system for HSYA fluorescence was established. In the optimized sensitization system, the fluorescence intensity of HSYA increased by 20 times and showed a good linearity with HSYA concentrations in the range of 0∼10 μM with a detection limit of 8 nM. The borax-HSYA sensitization system is nontoxic to T24 cells and mice and can be used for the fluorescence imaging of HSYA in cells, thereby providing an effective method for analyzing HSYA in vitro and monitoring its metabolism in cells.

Research on Photochromic Materials with Synthesis and Application of 1-(2-methyl-3-benzothienyl)-2-[2-methyl-(5-ethynyl)trimethylsilane-3-thienyl] Perfluorocyclopentene

2014 ◽  
Vol 1003 ◽  
pp. 35-38
Author(s):  
Le Le Ma ◽  
Hong Yan Xu ◽  
Gang Liu
Keyword(s):  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Uv Light ◽  
Optoelectronic Properties ◽  
Closed Ring ◽  
Open Ring ◽  
Photochromic Materials ◽  
Hexane Solution

A new unsymmetrical photochromic diarylethene compound, 1-(2-methyl-3-benzothienyl)-2-(2-methyl-(5-ethynyl) trimethylsilane-3-thienyl) perfluorocyclopentene (1o) has been synthesized, and its optoelectronic properties, such as photochromism and the fluorescence spectra of diarylethene 1o in hexane solution was investigated. The results showed that this compound exhibited reversible photochromism in solution. The maxima absorption of compound closed-ring isomer 1c are 538 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

Synthesis and Properties of 1,2-Bis[2-Methyl-5-(9,9-Dihexyl-Fluorene)-3-Thienyl]Perfluorocyclopentene

2014 ◽  
Vol 662 ◽  
pp. 103-106
Author(s):  
Le Le Ma ◽  
Gang Liu
Keyword(s):  
Visible Light ◽  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Uv Light ◽  
Optoelectronic Properties ◽  
Acetonitrile Solution ◽  
Closed Ring ◽  
Open Ring

A new symmetrical photochromic diarylethene 1,2-bis [2-methyl-5-(9,9-dihexyl-fluorene)-3-thienyl] perfluorocyclopentene (1o) has been synthesized, and its optoelectronic properties, such as photochromism and the fluorescence spectra of diarylethene 1o in acetonitrile solution was investigated. The maxima absorption of compound closed-ring isomer 1c is 619 nm. The open-ring isomer of the diarylethene 1o exhibited fluorescence at 390 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light,The results showed that this compound exhibited reversible photochromism and fluorescent switching in solution after irradiation with UV light and visible light.

Photochromism, Kinetics and Fluorescence of 1-(2-methyl-3-benzofuranyl)-2-[2-methyl-5-(4-cyanophenyl)-3-thienyl]perfluorocyclopentene

2014 ◽  
Vol 886 ◽  
pp. 175-178
Author(s):  
Dan Dan Xue ◽  
Zhi Yuan Sun ◽  
Shou Zhi Pu
Keyword(s):  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Uv Light ◽  
Photochromic Properties ◽  
Strong Fluorescence ◽  
Open Ring ◽  
Kinetics Of ◽  
Hexane Solution

An unsymmetrical photochromic diarylethene compound, 1-(2-methyl-3-benzofuranyl)-2-[2-methyl-5-(4-cyanophenyl)-3-thienyperfluorocyclopentene was synthesized, and its photochromic properties, kinetics of the photochromic cyclization/cycloreversion and fluorescence were investigated in detail. The compound exhibited good photochromism, changing from colorless to red after irradiation with 297 nm UV light, in which absorption maxima were observed at 530 nm in hexane solution. Simultaneously, cyclization/cycloreversion kinetics of this diarylethene was researched. The open-ring isomer of the diarylethene exhibited relatively strong fluorescence at 377 nm in hexane solution (2 × 10-5 mol L-1), when excited at 327 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. The fluorescence spectra of the diarylethene are depended on the concentration.

scholarly journals Garcinol loaded vitamin E TPGS emulsified PLGA nanoparticles: preparation, physicochemical characterization, in vitro and in vivo studies

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Raghuvir H. Gaonkar ◽  
Soumya Ganguly ◽  
Saikat Dewanjee ◽  
Samarendu Sinha ◽  
Amit Gupta ◽  
...  
Keyword(s):  
Vitamin E ◽  
Physicochemical Characterization ◽  
Plga Nanoparticles ◽  
In Vivo Studies ◽  
Vitamin E Tpgs

scholarly journals The Optimized Quantum Dots Mediated Thermometry Reveals the Efficiency of Myosin Extracted from Muscle Mini Bundles

2021 ◽  
Author(s):  
Meishan Li ◽  
Lucia Coppo ◽  
Bhanu P. Jena ◽  
Lars Larsson
Keyword(s):  
Quantum Dots ◽  
Heat Release ◽  
Fluorescence Intensity ◽  
Time Course ◽  
Enzymatic Reaction ◽  
Minimal Amount ◽  
Lower Efficiency ◽  
Fluorescent Intensity ◽  
Fast Myosin

Abstract Background: The quantum dots (QD) has been investigated as thermometrical sensor in biological microenvironment and applied to measure the muscle efficiency with underlying mechanisms, i.e., a reduction in fluorescent intensity of QD reflects an increase in temperature caused by heat release during ATP hydrolysis, denoting the efficiency of the motor protein myosin. The aim of this study is to optimize the QD mediated thermometry for measuring the efficiency of freshly extracted myosin from muscle mini bundles rather than pre-purified myosin and test this approach in preparations with different myosin isoform.Methods: The protocol of myosin extraction used in the single muscle fiber in vitro motility assay was modified slightly for extracting myosin from the muscle mini bundles. Moreover, the quantitation of extracted myosin was calculated from the total extracted protein since the ratio of myosin to total protein was constant, performing through spectrophotometric measurement of UV absorbance at 280 nm. The change in fluorescence intensity of QD thermometry measurement of myosin ATPase enzymatic reaction was plotted over time, and the slope of the linear negative regression between time course and relatively decreased fluorescence intensity was used to reflect the efficiency of extracted myosin. Results: The optimized QD mediated thermometry is established for evaluating the efficiency of myosin extracted from muscle mini bundles. Moreover, myosin isoform specific differences in the myosin efficiency were observed in comparison between slow myosin and fast myosin, i.e., the low myosin has lower efficiency than fast myosin, evidenced by a higher heat release.Conclusions: The optimized QD mediated thermometric measure of myosin efficiency in muscle mini bundles provides a nanoscale approach to evaluate myosin function based on a minimal amount of muscle, which is essentially required in the muscle research.

Synthesis and Photochromism of 1-(2-methyl-1-benzothiophene)-2-(2-methyl-5-aminomethane-3-thienyl)perfluorocyclopentene

2014 ◽  
Vol 886 ◽  
pp. 168-171 ◽  
Author(s):  
Le Le Ma ◽  
Hong Yan Xu ◽  
Shou Zhi Pu
Keyword(s):  
Fluorescence Intensity ◽  
Fluorescence Spectra ◽  
Uv Light ◽  
Optoelectronic Properties ◽  
Acetonitrile Solution ◽  
Strong Fluorescence ◽  
Closed Ring ◽  
Open Ring

A new unsymmetrical photochromic diarylethene 1-(2-methyl-3-benzothiophene)-2-(2-methyl-5-aminomethane-3-thienyl) perfluorocyclopentene was synthesized and its optoelectronic properties, such as photochromism and the fluorescence spectra of diarylethene1oin acetonitrile solution was investigated. The compound exhibited good photochromism in solution with alternating irradiation by UV/Vis light, and the maxima absorption of its closed-ring isomer1care 530 nm. The open-ring isomer of the diarylethene1oexhibited relatively strong fluorescence at 375 nm. Its fluorescence intensity decreased along with the photochromism from open-ring isomers to closed-ring isomers upon irradiation with 297 nm UV light.

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