In this paper, we report on water synthesis with a selective size of AgInS/ZnS quantum dots (QDs) coated with thioglycolic acid and on the analysis of their colloidal stability in water and physiological saline buffers to assess their potential use as a fluorescent label in bioanalysis. Nine fractions of AgInS/ZnS hydrophilic QDs were dispersed in buffer solutions with a wide pH range (3.5–9.5) and investigated by measuring the fluorescence intensity and zeta potential. The results demonstrate the possibility of using water-soluble thioglycolic acid-coated QDs as a surface ligand for immunofluorescent labeling using commonly used buffers. The highest QD stability was observed in the pH range (6.0- 9.5).
In this paper, we report the synthesis of hydrophilic luminescent quantum dots (QDs) of the core/shell structure using two approaches: high-temperature organic synthesis of CdZnSeS/ZnS and aqueous synthesis of AgInS/ZnS. Dihydrolipoic and thioglycolic acids have been used as surface ligands to impart hydrophilic properties. The influence of whole blood and serum on the optical properties of both types of QDs was evaluated for their application in blood analysis. It has been shown that AgInS/ZnS QDs with emission in the red spectral region (λPL = 638 nm) remained the most stable in whole blood samples and its optimal dilutions (up to 1:100, inclusive). Whereas CdZnSeS/ZnS fluorescent in the green region of the spectrum (λPL = 530 nm) showed the best signal of fluorescence (PL) intensity in blood serum samples.
In this contribution, we report synthesis of water-soluble Ag−In−S /ZnS quantum dots (QDs) using low toxic precursors as well as investigation of their optical properties. The QDs were successfully obtained directly in an aqueous environment in two ways: traditional one-pot water synthesis and hydrothermal synthesis in the presence of thioglycolic acid as a stabilizing and reactivity controlling agent. The effect of hydrothermal treatment on water-soluble Ag−In−S/ZnS QDs was shown and it was found that they are resistant for 4 hours autoclaving.
In this contribution, we report an efficient synthesis of Cd-free Ag−In−S /ZnS (AIS/ZnS) quantum dots (QDs) using low toxic precursors and investigation of their optical properties. The nanocrystals (NCs) have been successfully obtained directly in aqueous media in the presence of thioglycolic acid (TGA) as stabilizing and reactivity-controlling agent. The coating with ZnS shell leads to the photoluminescence (PL) emission peak blue-shift and the emission intensity enhancement. In order to increase the quantum yield (QY) the nanocrystals were transferred to the organic phase; an influence by post-synthesis treatments of heating was investigated.
Phantoms are an imitation of biological tissue, which are physically modeling the propagation of light in biological tissues. They are required for different purposes, and also repeatability of results is achieved with it. So the fabrication of solid tissue phantoms containing high absorb or luminescence nanoparticles is actual problems for experimenters. The work describes fabrication processing and characteristics of solid tissue phantoms.
We report an efficient synthesis Cd-free CuInS2/ZnS (CIS/ZnS) quantum dots (QDs) using low toxic precursors and investigation of their optical properties. The nanocrystals have been obtained via reaction between the acetate salts of the corresponding metals and elemental sulfur in the presence of dodecanethiol in octadecene media at 220°C. Influence of various experimental variables, including temperature, time, ratio of Cu and In precursors were investigated. Thus, it was shown that the photoluminescence (PL) emission wavelength can be tuned by conveniently changing the stoichiometric ratio of the components. The plain CIS nanocrystals did show PL emission but with quite low PL quantum yield (QY). In order to increase the QY of QD luminescence by compensation of the surface defects of QDs cores, the process of covering with ZnS shells was done. During shelling process, increasing of QY and blue shift of emission maximum were detected.
Control methods of temperature fields inside a tissue during laser photothermolysis are an important point to develop biomedical applications of thermal destructions of cancer. One of the most promising approaches to measure and to control of temperature is the application of luminescence nanothermometers such as CuInS2 nanoparticles. Temperature measurement can be carried out by determination of the maximum of the luminescence band. Thus, we have investigated the influence of exposure time and temperature on the position of the maximum of the luminescence band of CuInS2 nanoparticles.
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