Quantum dots Dotaz Zobrazit nápovědu
Nanoparticles are used in a wide range of disciplines due to their properties. The most common preparation is by physical and chemical synthesis, which uses a toxic chemicals that are not environmentally friendly and also limits the potential of the nanoparticles in their clinical applications. It is because of the negative properties of nanoparticles prepared by classical synthesis that a new type of synthesis comes to the fore. This is made possible by the ability of organisms to biosynthesize the nanoparticles either in the body or in the environment. Ability of the biosynthesis was demonstrated in a variety of microorganisms, but also in arthropods or even in mammals. Biosynthesis ability of organisms can be used both for the preparation of nanoparticles and for the reduction of contamination, since the raw materials for the synthesis are obtained from the environment. Biosynthesis by microorganisms could be a suitable alternative to conventional synthesis of quantum dots, mainly due to their low demands on the feedstock and the resulting biocompatibility of nanoparticles.
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.
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- elektroforéza kapilární metody MeSH
- kvantové tečky chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
This review is aimed on the interaction of quantum dots with tumor cells by fluorescence microscopy, we analyze the possibilities of the usage of QDs in tumor cell detection and visualization by fluorescence microscopy. QDs are fluorescent nanoparticles with good fluorescence properties. Specifically modified QDs can be targeted to the tumor tissue. QDs can be modified by antibodies, proteins, carbohydrates etc. For the use of QDs in biological applications, their solubility in water, stability and biocompatibility is important. Fluorescence microscopy is a good tool to observe interaction of QDs with cells and enable direct differentiation of normal and tumor cells.
- MeSH
- fluorescence MeSH
- fluorescenční mikroskopie * MeSH
- kvantové tečky * MeSH
- lidé MeSH
- nádory * diagnóza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Semiconductor quantum dots (QDs) are nanoparticles in which charge carriers are three dimensionally or quantum confined. The quantum confinement provides size-tunable absorption bands and emission color to QDs. Also, the photoluminescence (PL) of QDs is exceptionally bright and stable, making them potential candidates for biomedical imaging and therapeutic interventions. Although fluorescence imaging and photodynamic therapy (PDT) of cancer have many advantages over imaging using ionizing radiations and chemo and radiation therapies, advancement of PDT is limited due to the poor availability of photostable and NIR fluorophores and photosensitizing (PS) drugs.
BACKGROUND: Quantum dots are an emerging nanomaterial with broad use in technical disciplines; however, their application in the field of biomedicine becomes also relevant and significant possibilities have appeared since the discovery in 1980s. OBJECTIVE: The current review is focused on the therapeutic applications of quantum dots which become an emerging use of the particles. They are introduced as potent carriers of drugs and as a material well suited for the diagnosis of disparate pathologies like visualization of cancer cells or pathogenic microorganisms. CONCLUSION: Quantum dots toxicity and modifications for the toxicity reduction are discussed here as well. Survey of actual papers and patents in the field of quantum dots use in the biomedicine is provided.
Quantum dots (QDs) are small semiconductor nanoparticles with great optical properties. Their behaviour enables the usage of QDs in in vitro and in vivo experiments and they are promising tools in disease treatment and targeted therapy. The limitation of their usage is the toxicity. Quantum dots consist of different metals, which have various effects on the health. To decrease their toxicity, different surface coatings are used. The effect of QDs on the organism can be tested on chicken embryos. Chicken embryos represent great model for QDs toxicity studies, because there is no need of any permission for the work with embryos and the experiments are low cost and fast.
The anti-DNA antibodies are produced in patients with autoimmune disease called systemic lupus erythematodes. They can be reactive against double or single stranded DNA or DNA modified with some other molecules. Using the variety of antibodies it is possible to determine the structure of studied DNA. In this work, we used 4 anti-DNA antibodies produced in egg yolk after immunization of hens with DNA-mBSA antigen – anti-dsDNA, anti-ssDNA, afi-dsDNA and afi-ssDNA. The reactivity of these antibodies was evaluated using the dot blot method with different lengths and concentrations of DNA antigen. The most reactive antibodies (anti-ssDNA) were modified with carbon quantum dots synthesized from multiwall carbon nanotubes and this modification was verified by ELISA-like method with fluorescent detection and fluorescence resonance energy transfer between DNA and quantum dots was observed, increasing the sensitivity of the DNA detection.
Nanoparticles have gained increasing interest in medical and in vivo applications. Metallothionein (MT) is well known as a maintainer of metal ions balance in intracellular space. This is due to high affinity of this protein to any reactive species including metals and reactive oxygen species. The purpose of this study was to determine the metallothionein-quantum dots interactions that were investigated by spectral and electrochemical techniques. CuS, CdS, PbS, and CdTe quantum dots (QDs) were analysed. The highest intensity was shown for CdTe, than for CdS measured by fluorescence. These results were supported by statistical analysis and considered as significant. Further, these interactions were analysed using gel electrophoresis, where MT aggregates forming after interactions with QDs were detected. Using differential pulse voltammetry Brdicka reaction, QDs and MT were studied. This method allowed us to confirm spectral results and, moreover, to observe the changes in MT structure causing new voltammetric peaks called X and Y, which enhanced with the prolonged time of interaction up to 6 h.
Water-soluble CdTe quantum dots (QDs) and their conjugates with antibodies and antigenes were prepared by optimized procedures for applications in CE immunoassays. The QD size of 3.5 nm, excitation spectrum in the range of 300-500 nm, the maximum wavelength of the emission spectrum at 610 nm, quantum yield of 0.25 and luminescence lifetimes in the range of 3.6-43 ns were determined. The 0.1 M solution of TRIS/TAPS (pH 8.3) was found to be the optimum buffer for the separation of the antiovalbumin-ovalbumin immunocomplex from the free conjugates of QDs.
Interestingly, even though the absorption maximum of prepared capped carbon quantum dots (CQDs) is 210 nm and the emission maximum is 392 nm, using capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) with excitation wavelength of 470 nm and long pass emission filter (510 nm) a signal was observed. Application of separation technique reviled presence of two different species, which corresponded to two well-resolved peaks present in the electropherogram. This fact is probably caused by presence of particles of different sizes.
