Photochemical Events during the Photosensitization of Hypocrellin A on ZnS Quantum Dots

2012 ◽  
Vol 581-582 ◽  
pp. 574-577 ◽  
Author(s):  
Wei Liu ◽  
Xian Lan Chen ◽  
La Shi Yang ◽  
Ju Cheng Zhang ◽  
Ping Yi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Fluorescence Quenching ◽  
Strong Interaction ◽  
Organic Dyes ◽  
Synthesis Method ◽  
Raw Material ◽  
Phase Synthesis ◽  
Hypocrellin A ◽  
Optimum Ph

Hypocrellin A is organic dyes with more superior visible light performance, which has resistant tumor activity and becomes widely accepted. In this paper, acetone is used as solvent to extract, separate and purify the hypocrellin A. With ZnCl2 and Na2S as raw material, ZnS Quantum dots (QDs) were prepared by water-phase synthesis method under the role of the magnetic stirrer. Fluorescence detection results showed that the optimum pH of the ZnS QDs and HA solution close to neutral (6.86). The fluorescence quenching of hypocrellin A is most obvious as the ZnS QDs was added, because of the strong interaction was generated between HA and ZnS QDs, resulting in the fluorescence quenching.

scholarly journals Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3313 ◽  
Author(s):  
Łukasz Janus ◽  
Julia Radwan-Pragłowska ◽  
Marek Piątkowski ◽  
Dariusz Bogdał
Keyword(s):  
Quantum Dots ◽  
Chemical Structure ◽  
Water Solubility ◽  
Organic Dyes ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
The Novel ◽  
Surface Modified ◽  
Synthesis Approach ◽  
Effective Analysis

Recently, fluorescent probes became one of the most efficient tools for biosensing and bioimaging. Special attention is focused on carbon quantum dots (CQDs), which are characterized by the water solubility and lack of cytotoxicity. Moreover, they exhibit higher photostability comparing to traditional organic dyes. Currently, there is a great need for the novel, luminescent nanomaterials with tunable properties enabling fast and effective analysis of the biological samples. In this article, we propose a new, ecofriendly bottom-up synthesis approach for intelligent, surface-modified nanodots preparation using bioproducts as a raw material. Obtained nanomaterials were characterized over their morphology, chemical structure and switchable luminescence. Their possible use as a nanodevice for medicine was investigated. Finally, the products were confirmed to be non-toxic to fibroblasts and capable of cell imaging.

scholarly journals Efficient Photoluminescence of Mn2+-Doped ZnS Quantum Dots Sensitized by Hypocrellin A

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xianlan Chen ◽  
Wei Liu ◽  
Guowei Zhang ◽  
Na Wu ◽  
Ling Shi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Transfer ◽  
Fluorescence Quenching ◽  
Absorption Spectra ◽  
Particle Surface ◽  
Key Factors ◽  
Heterogeneous Electron Transfer ◽  
Hypocrellin A ◽  
Singlet States ◽  
Doping Technique

Mn2+-doped ZnS semiconductor quantum dots reveal remarkably intense photoluminescence with the4T1(4G) f6A1(6S) transition. In this study, following growth doping technique, Mn2+-doped ZnS quantum dots (ZnS:Mn2+QDs) with high-quality optical properties and narrow size distribution were synthesized successfully. The dopant emission has been optimized with various reaction parameters, and it has been found that the percentage of introduced dopant, reaction temperature, and time as well as the pH of a reaction mixture are key factors for controlling the intensity. Photoluminescence emission (PL) measurements of ZnS:Mn2+QDs show Mn2+d-d orange luminescence along with band-edge blue luminescence. Moreover, the electron transfer from singlet states of hypocrellin A (HA) to colloidal ZnS:Mn2+QDs has been examined by absorption spectra and fluorescence quenching. The absorption spectrum gave an evidence of the increases in the extinction coefficient and the red-shift of the absorption maxima in the absorption spectra of HA in the presence of ZnS:Mn2+QDs, demonstrating the occurrence of surface interactions between the sensitizer and the particle surface. Fluorescence quenching by ZnS:Mn2+QDs also suggested that there were a complex association between HA and ZnS:Mn2+QDs, which was necessary for observing the heterogeneous electron-transfer process at the interface of sensitizer-semiconductor.

Preparation ZnS Quantum Dots via Water-Phase Synthesis Method

2013 ◽  
Vol 706-708 ◽  
pp. 230-233
Author(s):  
Wei Liu ◽  
Xian Lan Chen ◽  
Ju Cheng Zhang ◽  
Yun Hui Long ◽  
Ling Shi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ph Value ◽  
Synthesis Method ◽  
Emission Spectra ◽  
Water Phase ◽  
Complexing Agents ◽  
Complex Ions ◽  
Aqueous Synthesis ◽  
Phase Synthesis ◽  
Optimal Reaction

With water as the medium, PVP as stabilizer and ammonia as complexing agents and adjusting pH value of the solution, we report an all-aqueous synthesis of highly photoluminescent and stable ZnS quantum dots (QDs) by water-phase synthesis reaction between ZnCl2 and NaS at different temperatures and times. The optimal reaction conditions of PVP-capped ZnS QDs were obtained through experiment as follows: the concentration ZnCl2 and NaS solution both are 1 mM, (PVP):(ZnCl2) = 0.0167 (v/v), (NH3):(ZnCl2)=1:300 (v/v), the optimal reaction temperature is 40 °C, the optimal reaction time is 30 min. With ammonia as complexing agents, Zn(OH)2 can dissolve in ammonia and form to complex ions ((Zn(NH3)4)2+), which make Zn2+ release slowly to control the nucleus growth rate of ZnS, thus obtain small size of nanoparticles. The fluorescence spectra shows that the emission peaks of ZnS QDs around ~395 nm and ~470 nm on the emission spectra, which are consistent with literatures, so nano-ZnS QDs was synthesized successfully in this paper.

scholarly journals Quantum Dots: Method of Preparation and Biological Application

2019 ◽  
Vol 9 (4-s) ◽  
pp. 670-672 ◽  
Author(s):  
Amol Gomase ◽  
Sagar Sangale ◽  
Akshay Mundhe ◽  
Pravin Gadakh ◽  
Vikrant Nikam
Keyword(s):  
Drug Delivery ◽  
Quantum Dots ◽  
Chemical Synthesis ◽  
Synthesis Method ◽  
Biological Application ◽  
Semiconductor Crystal ◽  
Phase Synthesis ◽  
Light Emitting ◽  
Inorganic Semiconductor ◽  
Conductive Property

Quantum dots are inorganic semiconductor crystal of nanometer size which having distinctive conductive property depend on its size & shape. After administration of quantum dots parentally they identify target and bound them. Also quantum dots having light emitting property depend on size & shape. Quantum dots are prepared by chemical synthesis method include both organic & water phase synthesis & also by top- bottom approach. Tumor cell targeting & detection of pathogen & toxin are the main application of quantum dots & also in targeting drug delivery system. This review provides the overview of method of preparation of quantum dots & its biological application. Keywords: Quantum dot, targeting drug delivery, biological application

Semiconductor Quantum Dots for Multicolor Fluorescence Imaging and Spectroscopy of Single Cancer Cells

2003 ◽  
Vol 773 ◽  
Author(s):  
Xiaohu Gao ◽  
Shuming Nie ◽  
Wallace H. Coulter
Keyword(s):  
Quantum Dots ◽  
Cancer Cells ◽  
Fluorescence Imaging ◽  
Organic Dyes ◽  
Fluorescent Proteins ◽  
Single Cells ◽  
Quantitative Imaging ◽  
Semiconductor Quantum Dots ◽  
Single Cancer ◽  
Imaging And Spectroscopy

AbstractLuminescent quantum dots (QDs) are emerging as a new class of biological labels with unique properties and applications that are not available from traditional organic dyes and fluorescent proteins. Here we report new developments in using semiconductor quantum dots for quantitative imaging and spectroscopy of single cancer cells. We show that both live and fixed cells can be labeled with multicolor QDs, and that single cells can be analyzed by fluorescence imaging and wavelength-resolved spectroscopy. These results raise new possibilities in cancer imaging, molecular profiling, and disease staging.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

Detection of Glucose in Human Serum Based on Silicon Dot Probe

2020 ◽  
Vol 16 (6) ◽  
pp. 744-752
Author(s):  
Kuan Luo ◽  
Xinyu Jiang
Keyword(s):  
Quantum Dots ◽  
Blood Glucose ◽  
Human Serum ◽  
Organic Dyes ◽  
Limit Of Detection ◽  
Fasting Blood Glucose ◽  
Glucose Biosensor ◽  
Metal Nanoclusters ◽  
Glucose Levels ◽  
Highly Sensitive

Background: Diabetes Mellitus (DM) is a major public metabolic disease that influences 366 million people in the world in 2011, and this number is predicted to rise to 552 million in 2030. DM is clinically diagnosed by a fasting blood glucose that is equal or greater than 7 mM. Therefore, the development of effective glucose biosensor has attracted extensive attention worldwide. Fluorescence- based strategies have sparked tremendous interest due to their rapid response, facile operation, and excellent sensitivity. Many fluorescent compounds have been employed for precise analysis of glucose, including quantum dots, noble metal nanoclusters, up-converting nanoparticles, organic dyes, and composite fluorescent microspheres. Silicon dot as promising quantum dots materials have received extensive attention, owing to their distinct advantages such as biocompatibility, low toxicity and high photostability. Methods: MnO2 nanosheets on the Si nanoparticles (NPs) surface serve as a quencher. Si NPs fluorescence can make a recovery by the addition of H2O2, which can reduce MnO2 to Mn2+, and the glucose can thus be monitored based on the enzymatic conversion of glucose by glucose oxidase to generate H2O2. Therefore, the glucose concentration can be derived by recording the fluorescence recovery spectra of the Si NPs. Results: This probe enabled selective detection of glucose with a linear range of 1-100 μg/mL and a limit of detection of 0.98 μg/mL. Compared with the commercial glucometer, this method showed favorable results and convincing reliability. Conclusion: We have developed a novel method based on MnO2 -nanosheet-modified Si NPs for rapid monitoring of blood glucose levels. By combining the highly sensitive H2O2/MnO2 reaction with the excellent photostability of Si NPs, a highly sensitive, selective, and cost-efficient sensing approach for glucose detection has been designed and applied to monitor glucose levels in human serum with satisfactory results.

scholarly journals Rheological Characterization of a Concentrated Phosphate Slurry

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 178
Author(s):  
Souhail Maazioui ◽  
Abderrahim Maazouz ◽  
Fayssal Benkhaldoun ◽  
Driss Ouazar ◽  
Khalid Lamnawar
Keyword(s):  
Flow Behavior ◽  
Continuous Phase ◽  
Raw Material ◽  
Rheological Characterization ◽  
Phosphate Ore ◽  
Insoluble Particles ◽  
Experimental Protocols ◽  
Solid Liquid

Phosphate ore slurry is a suspension of insoluble particles of phosphate rock, the primary raw material for fertilizer and phosphoric acid, in a continuous phase of water. This suspension has a non-Newtonian flow behavior and exhibits yield stress as the shear rate tends toward zero. The suspended particles in the present study were assumed to be noncolloidal. Various grades and phosphate ore concentrations were chosen for this rheological investigation. We created some experimental protocols to determine the main characteristics of these complex fluids and established relevant rheological models with a view to simulate the numerical flow in a cylindrical pipeline. Rheograms of these slurries were obtained using a rotational rheometer and were accurately modeled with commonly used yield-pseudoplastic models. The results show that the concentration of solids in a solid–liquid mixture could be increased while maintaining a desired apparent viscosity. Finally, the design equations for the laminar pipe flow of yield pseudoplastics were investigated to highlight the role of rheological studies in this context.

Sign in / Sign up

Export Citation Format

Share Document