Application of CdTe/ZnSe Quantum Dots in In Vitro Imaging of Chicken Tissue and Embryo

The present work is aimed to synthesize CdTe/ZnSe core/shell quantum dots (QDs) in an easy way and to explore the possibilities of its application in in vitro imaging of chicken tissue and embryo. The QDs were prepared using microwave irradiation with different temperatures, which is a very easy and less time‐consuming method. Subsequently, these QDs were characterized by spectrofluorimetry, Transmission Electron Microscopy, X‐ray fluorescence analysis and Dynamic Light Scattering measurement. A blueshifting of the emission was found when ZnSe was deposited on CdTe QDs. The QDs showed its fluorescence emission quantum yields up to 25%. They were applied into chicken embryos and breast muscle tissues to study their efficiency in in vitro imaging. All the QDs of different color were able to visualize in in vitro imaging. The highest fluorescence intensity was detected in the case of red QDs prepared at 100°C. The green and red QDs were possible to detect up to the depth of 3 and 4 mm of the tissue, respectively.     

Preconcentration based on paramagnetic microparticles for the separation of sarcosine using hydrophilic interaction liquid chromatography coupled with coulometric detection

Sarcosine has been identified as a potential prostate cancer marker. To provide determination of this compound, a number of methods are developing. In this study, we optimized a method for its separation by hydrophilic interaction LC with electrochemical detection (ED). Due to the fact that mobile phases commonly used for this type of separation altered the LODs measured by electrochemical detectors, we applied postcolumn dosing of buffer suitable for ED. The optimized conditions were mobile phase A acetonitrile, mobile phase B water in the ratio A/B 70:30, with postcolumn addition of mobile phase C (200 mM phosphate buffer pH 9). The optimal mixing ratio was A + B/C 1:1 with a flow rate of 0.80 mL/min (0.40 + 0.40 mL/min) and detection potential of 1000 mV. Due to the optimization of the parameters for effective separation, which had to meet the optimal parameters of ED, we reached a good resolution for separation also with a good LOD (100 nM). In addition, we successfully carried out sarcosine analysis bound on our modified paramagnetic microparticles with the ability to preconcentrate sarcosine isolated from artificial urine.     

Capillary electrophoresis of quantum dots: Minireview

It has been already three decades, since the fluorescent nanocrystals called quantum dots (QDs) appeared and attracted attention of a broad scientific community. Their excellent not only optical but also electronic properties predetermined QDs for utilization in a variety of areas. Besides lasers, solar cells, and/or computers, QDs have established themselves in the field of (bio)chemical labeling as well as medical imaging. However, due to the numerous application possibilities of QDs, there are high demands on their properties that need to be precisely controlled and characterized. CE with its versatile modes and possibilities of detection was found to be an effective tool not only for characterization of QDs size and/or surface properties but also for monitoring of their interactions with other molecules of interest. In this minireview, we are giving short insight in analysis of QDs by CE, and summarizing the advantages of this method for QDs characterization.     

Study of DNA-ellipticine interaction by capillary electrophoresis with laser-induced fluorescence detection

Ellipticine (5,11-dimethyl-6H-pyrido[4,3-b]carbazole), an alkaloid isolated from Apocynaceae plants, exhibits an antitumor activity, which is exceptionally high against several specific types of tumors. Ellipticine is also interesting as an anticancer drug as it has limited side effects and lacks of hematological toxicity. Various methods to study intercalating activity of this drug have been developed. However, to our best knowledge, capillary electrophoresis (CE) as a technique combining high separation resolution with various detection options has never been used for these purposes. In this study, a novel separation method based on CE with laser-induced fluorescence (CE-LIF) detection has been developed for the determination of ellipticine and for the monitoring of ellipticine-DNA interaction. Sodium acetate (50 mM, pH 4.5) was used as a background electrolyte and LIF detection at λ(ex) = 488 nm. The limit of detection for ellipticine was determined to be 5 × 10?? M. A total of 20% dimethyl sulfoxide was found optimal as sample solvent. Additionally, intercalation of ellipticine into the double-stranded DNA was investigated. Signal corresponding to ellipticine was decreasing and a new peak appeared and was growing. It can be concluded that CE-LIF is a method applicable to in vitro studies of ellipticine-DNA complexes.     

Structural changes in metallothionein isoforms revealed by capillary electrophoresis and Brdicka reaction

Metallothionein (MT) as a potential cancer marker is at the center of interest and its properties, functions and behavior under various conditions is intensively studied. In the present study, two major mammalian MT isoforms (MT‐1 and MT‐2) were separated using capillary electrophoresis (CE) coupled with UV detector in order to describe their basic behavior. Under the optimized conditions, the separation of both isoforms was enabled as well as estimation of detection limits as subunits and units of ng per μL for MT‐2 and MT‐1, respectively. Further, the effects of thermal treatment and the presence of denaturing agent such as urea on MT‐1 and MT‐2 isoforms were studied by CE‐UV. Thermal treatment caused an increase in the signals of both isoforms. A new parameter called precipitation rate has been defined based on this finding. This parameter can be expressed as a slope of the linear regression of the time dependency curve recalculated on the MT concentration. The thermal precipitation rate for MT‐1 and MT‐2 was determined as 1.1 and 0.9 ng of MT/min, respectively. The chemical precipitation rate calculated from the linear regression for both isoforms provided the same value of 0.25 ng of MT/min. The results were confirmed by manual spectrometric measurements and by differential pulse voltammetry Brdicka reaction. Based on these results, a model of MT behavior under the conditions studied was suggested.     

Two Positions of Potassium in Chemically Doped C(60) Peapods: An in situ Spectroelectrochemical Study

The state of doping of fullerene peapods C60@SWCNT treated with K vapor was studied by in situ Raman spectroelectrochemistry. For all samples under study, a heavy chemical n doping was proved by the vanishing of the radial breathing mode and the downshift of tangential displacement mode. The K-treated peapods remain partly doped even if they are exposed to humid air. The Ag(2) mode of intratubular fullerene in K-doped peapods in contact with air was still redshifted as referred to its position in pristine peapods. Potassium inserted into the peapods is the reason for the air-insensitive residual doping, which can be removed only by electrochemical oxidation. This indicates the presence of two positions of potassium in doped sample.     

IR laser decomposition of 1,3-disilacyclobutane in presence of carbon disulfide: chemical vapour deposition of polythiacarbosilane

TEA CO₂ laser irradiation of gaseous mixtures of 1,3-disilacyclobutane - carbon disulfide affords chemical vapour deposition of solid polythiacarbosilane films that possess Si-S-X (X = Si, C), S-H and Si-H bonds and undergo slow hydrolysis in air to polyoxothiacarbosilanes containing Si-H, Si-O-Si and (C)S-H bonds. The formation of the polythiacarbosilane is proposed to take place via polymerization of transient silene and incorporation of CS₂ into growing polysilene network.     

Effects of low-power laser irradiation on cell locomotion in protozoa

Low-power lasers are commonly used in human medicine for treatment of various pathological conditions, but mechanisms of their healing effects are still poorly understood. The results of this study provide information related to these effects at the cellular level. Two different protozoan species, Euglena gracilis and Tetrahymena thermophila, were used to study changes in locomotion behavior in response to low-power lasers. The cells were irradiated at 830 and 650 nm generated by a semiconductor laser (99 J/cm2, 360 mW) and a laser pointer (0.75 J/cm2, 5 mW), respectively, and their locomotion was recorded by a TV camera and analyzed using computer software. Exposure to laser light, regardless of the wavelength, resulted in increased cell velocity in both species (P <0.001). Exposure to 650 nm produced an equal increase in median cell velocity in both E. gracilis (19.0%) and T. thermophila (18.2%), and some increase persisted in the postirradiation 30 s period. Irradiation by the 830 nm laser resulted in a markedly higher response in Tetrahymena (29.4%) than in Euglena (15.2%), and the two median values remained increased after irradiation was discontinued. Different reactions found in the species studied and some mechanisms underlying the response of cells to radiation are discussed.