Interactions between CdTe quantum dots and DNA revealed by capillary electrophoresis with laser-induced fluorescence detection.

Quantum dots (QDs) are one of the most promising nanomaterials, due to their size-dependent characteristics as well as easily controllable size during the synthesis process. They are promising label material and their interaction with biomolecules is of great interest for science. In this study, CdTe QDs were synthesized under optimal conditions for 2 nm size. Characterization and verification of QDs synthesis procedure were done by fluorimetric method and with CE. Afterwards, QDs interaction with chicken genomic DNA and 500 bpDNA fragment was observed employing CE-LIF and gel electrophoresis. Performed interaction relies on possible matching between size of QDs and major groove of the DNA, which is approximately 2.1 nm.

Quantum dots and prion proteins: is this a new challenge for neurodegenerative diseases imaging?

A diagnostics of infectious diseases can be done by the immunologic methods or by the amplification of nucleic acid specific to contagious agent using polymerase chain reaction. However, in transmissible spongiform encephalopathies, the infectious agent, prion protein (PrP(Sc)), has the same sequence of nucleic acids as a naturally occurring protein. The other issue with the diagnosing based on the PrP(Sc) detection is that the pathological form of prion protein is abundant only at late stages of the disease in a brain. Therefore, the diagnostics of prion protein caused diseases represent a sort of challenges as that hosts can incubate infectious prion proteins for many months or even years. Therefore, new in vivo assays for detection of prion proteins and for diagnosis of their relation to neurodegenerative diseases are summarized. Their applicability and future prospects in this field are discussed with particular aim at using quantum dots as fluorescent labels.

Nanocarriers for anticancer drugs--new trends in nanomedicine.

This review provides a brief overview of the variety of carriers employed for targeted drug delivery used in cancer therapy and summarizes advantages and disadvantages of each approach. Particularly, the attention was paid to polymeric nanocarriers, liposomes, micelles, polyethylene glycol, poly(lactic-co-glycolic acid), dendrimers, gold and magnetic nanoparticles, quantum dots, silica nanoparticles, and carbon nanotubes. Further, this paper briefly focuses on several anticancer agents (paclitaxel, docetaxel, camptothecin, doxorubicin, daunorubicin, cisplatin, curcumin, and geldanamycin) and on the influence of their combination with nanoparticulate transporters to their properties such as cytotoxicity, short life time and/or solubility.

Glutathione modified CdTe quantum dots as a label for studying DNA interactions with platinum based cytostatics.

Cisplatin, carboplatin, and oxaliplatin represent three generations of platinum based drugs applied successfully for cancer treatment. As a consequence of the employment of platinum based cytostatics in the cancer treatment, it became necessary to study the mechanism of their action. Current accepted opinion is the formation of Pt-DNA adducts, but the mechanism of their formation is still unclear. Nanomaterials, as a progressively developing branch, can offer a tool for studying the interactions of these drugs with DNA. In this study, fluorescent CdTe quantum dots (QDs, λem = 525 nm) were employed to investigate the interactions of platinum cytostatics (cisplatin, carboplatin, and oxaliplatin) with DNA fragment (500 bp, c = 25 µg/mL). Primarily, the fluorescent behavior of QDs in the presence of platinum cytostatics was monitored and major differences in the interaction of QDs with tested drugs were observed. It was found that the presence of carboplatin (c = 0.25 mg/mL) had no significant influence on QDs fluorescence; however cisplatin and oxaliplatin quenched the fluorescence significantly (average decrease of 20%) at the same concentration. Subsequently, the amount of platinum incorporated in DNA was determined by QDs fluorescence quenching. Best results were reached using oxaliplatin (9.4% quenching). Linear trend (R(2) = 0.9811) was observed for DNA platinated by three different concentrations of oxaliplatin (0.250, 0.125, and 0.063 mg/mL). Correlation with differential pulse voltammetric measurements provided linear trend (R(2) = 0.9511). As a conclusion, especially in the case of oxaliplatin-DNA adducts, the quenching was the most significant compared to cisplatin and nonquenching carboplatin.

Modern micro and nanoparticle-based imaging techniques.

The requirements for early diagnostics as well as effective treatment of insidious diseases such as cancer constantly increase the pressure on development of efficient and reliable methods for targeted drug/gene delivery as well as imaging of the treatment success/failure. One of the most recent approaches covering both the drug delivery as well as the imaging aspects is benefitting from the unique properties of nanomaterials. Therefore a new field called nanomedicine is attracting continuously growing attention. Nanoparticles, including fluorescent semiconductor nanocrystals (quantum dots) and magnetic nanoparticles, have proven their excellent properties for in vivo imaging techniques in a number of modalities such as magnetic resonance and fluorescence imaging, respectively. In this article, we review the main properties and applications of nanoparticles in various in vitro imaging techniques, including microscopy and/or laser breakdown spectroscopy and in vivo methods such as magnetic resonance imaging and/or fluorescence-based imaging. Moreover the advantages of the drug delivery performed by nanocarriers such as iron oxides, gold, biodegradable polymers, dendrimers, lipid based carriers such as liposomes or micelles are also highlighted.

Biotin-modified glutathione as a functionalized coating for bioconjugation of CdTe-based quantum dots.

In this study, biotin-conjugated glutathione was synthesized using peptide bonding of the biotin carboxy group and amino group of the γ-glutamic acid to prepare an alternative coating for CdTe quantum dots (QDs). This type of coating combines the functionality of the biotin with the fluorescent properties of the QDs to create a specific, high-affinity fluorescent probe able to react with avidin, streptavidin and/or neutravidin. Biotin-functionalized glutathione-coated CdTe QDs were prepared by a simple one-step method using Na2 TeO3 and CdCl2. Obtained QDs were separated from the excess of the biotin-conjugated glutathione by CE employing 300 mM borate buffer with pH 7.8 as a background electrolyte. The detection of sample components was performed by the photometric detection at 214 nm and LIF employing Ar⁺ ion laser (488 nm).

Magnetic nanoparticles and targeted drug delivering.

Magnetic nanoparticles (MNPs) are being of great interest due to their unique purposes. Especially in medicine, application of MNPs is much promising. MNPs have been actively investigated as the next generation of targeted drug delivery for more than thirty years. The importance of targeted drug delivery and targeted drug therapy is to transport a drug directly to the centre of the disease under various conditions and thereby treat it deliberately, with no effects on the body. Usage of MNPs depends largely on the preparation processes to select optimal conditions and election agents to modify their surface. This review summarizes the most commonly used functionalization methods of the MNPs preparation methods and their use in targeted drug delivery and targeted therapy.