Vojtech Adam

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.

Methods for carbon nanotubes synthesis—review

Carbon nanotubes (CNTs) have been under scientific investigation for more than fifteen years because of their unique properties that predestine them for many potential applications. The field of nanotechnology and nanoscience push their investigation forward to produce CNTs with suitable parameters for future applications. It is evident that new approaches of their synthesis need to be developed and optimized. In this paper we review history, types, structure and especially the different synthesis methods for CNTs preparation including arc discharge, laser ablation and chemical vapour deposition. Moreover, we mention some rarely used ways of arc discharge deposition which involves arc discharge in liquid solutions in contrary to standard used deposition in a gas atmosphere. In addition, the methods for uniform vertically aligned CNTs synthesis using lithographic techniques for catalyst deposition as well as a method utilizing a nanoporous anodized aluminium oxide as a pattern for selective CNTs growth are reported too.

The Role of Metallothionein in Oxidative Stress

Free radicals are chemical particles containing one or more unpaired electrons, which may be part of the molecule. They cause the molecule to become highly reactive. The free radicals are also known to play a dual role in biological systems, as they can be either beneficial or harmful for living systems. It is clear that there are numerous mechanisms participating on the protection of a cell against free radicals. In this review, our attention is paid to metallothioneins (MTs) as small, cysteine-rich and heavy metal-binding proteins, which participate in an array of protective stress responses. The mechanism of the reaction of metallothioneins with oxidants and electrophilic compounds is discussed. Numerous reports indicate that MT protects cells from exposure to oxidants and electrophiles, which react readily with sulfhydryl groups. Moreover, MT plays a key role in regulation of zinc levels and distribution in the intracellular space. The connections between zinc, MT and cancer are highlighted.

Quantum dots - characterization, preparation and usage in biological systems.

The use of fluorescent nanoparticles as probes for bioanalytical applications is a highly promising technique because fluorescence-based techniques are very sensitive. Quantum dots (QDs) seem to show the greatest promise as labels for tagging and imaging in biological systems owing to their impressive photostability, which allow long-term observations of biomolecules. The usage of QDs in practical applications has started only recently, therefore, the research on QDs is extremely important in order to provide safe and effective biosensing materials for medicine. This review reports on the recent methods for the preparation of quantum dots, their physical and chemical properties, surface modification as well as on some interesting examples of their experimental use.

Deoxynivalenol and its toxicity.

Deoxynivalenol and its toxicity Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. The exposure risk to human is directly through foods of plant origin (cereal grains) or indirectly through foods of animal origin (kidney, liver, milk, eggs). It has been detected in buckwheat, popcorn, sorgum, triticale, and other food products including flour, bread, breakfast cereals, noodles, infant foods, pancakes, malt and beer. DON affects animal and human health causing acute temporary nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever. This review briefly summarizes toxicities of this mycotoxin as well as effects on reproduction and their antagonistic and synergic actions.

Noteworthy Secondary Metabolites Naphthoquinones – their Occurrence, Pharmacological Properties and Analysis

Chemical investigation of many bacterial and fungal, as well as plant species has revealed the presence of in- teresting compounds derived from naphthalene - 1,4-naphthoquinones and rarely also 1,2-naphthoquinones. They were detected in many species of families Bignoniaceae, Droseraceae, Plumbaginace, Boraginaceae, Juglandaceae as well as in species of small families, such as Dioncophyllaceae or Acanthaceae. Naphthoquinones have very interesting spectrum of biological actions, including antibiotic, antiviral, anti-inflammatory, antipyretic, antiproliferative and cytotoxic effects. Because of these properties the plants containing them are used in folk medicines, mainly by natives in Asia, where espe- cially Chinese medicine uses aerial as well as subterranean parts of these plants for hundreds years, and South America. The utilizing of naphthoquinones for medicinal purposes and their occurrence in nature is reviewed and discussed. Moreover, we review analytical techniques using for their analysis.

Metallothioneins and Cancer

Metallothioneins (MTs) are low molecular, cysteine-rich proteins that have naturally-occurring Zn(2+) in both clusters. They may serve as a reservoir of metals for synthesis of apoenzymes and zinc-finger transcription regulators. MTs are also involved with several important proteins e.g. p53, NF-kappaB, PKCl, and GTPase Rab3A. New biological roles for these proteins have been identified including those needed in the carcinogenic process. However, their use as a predictive marker remains controversial. Several reports have disclosed MTs expression as a prognostic factor for tumor progression and drug resistance in a variety of malignancies particularly breast, prostatic, ovarial, head and neck, non-small cell lung cancer, melanoma, and soft tissue sarcoma. The role of MTs as a tumor disease marker or as a cause of resistance in cancer treatment is reviewed and discussed. Moreover, we describe some analytical methods that were developed to detect MTs.

Anthracyclines and ellipticines as DNA-damaging anticancer drugs: Recent advances

Over the past forty years, anthracyclines and ellipticines have attracted attention as promising cytostatics. In this review, we focus on their mechanisms of cytoxicity, DNA-damaging effects and adverse side-effects. We also summarize ways to enhance the therapeutic effects of these drugs together with a decrease in their adverse effects. Current drug design strategies are focused on drug bioavailability and their tissue targeting, whereas drug delivery to specific intracellular compartments is rarely addressed. Therefore, therapies utilizing the antineoplastic activities of anthracyclines and ellipticines combined with novel strategies such as nanotechnologies for safer drug delivery, as well as strategies based on gene therapy, could significantly contribute to medical practice.

Quantum dots-fluorescence resonance energy transfer-based nanosensors and their application.

Fluorescence resonance energy transfer (FRET) in combination with quantum dots (QDs) and their superior properties has enabled designing of the new and improved sensors. In this review, the latest novelties in development and application of FRET nanosensors employing QDs are presented. QDs offer several advantages over organic dyes - broad excitation spectra, narrow defined tunable emission peak, longer fluorescence lifetime, resistance to photobleaching and 10-100 times higher molar extinction coefficient. These properties of QDs allow multicolor QDs to be excited from one source by common fluorescent dyes without emission signal overlap and results in brighter probes comparing to conventional fluorophores. Due to these benefits, QD-FRET-based nanosensors gained a wide spread popularity in a variety of scientific areas. These sensors are most frequently applied in the domain of the nucleic acid and enzyme activity detection. Other applications are detection of peptides and low-molecular compounds, environmental pollutants, viruses, microorganisms and their toxins, QD-FRET-based immunoassays, and pH sensors.

Fully automated spectrometric protocols for determination of antioxidant activity: advantages and disadvantages.

The aim of this study was to describe behaviour, kinetics, time courses and limitations of the six different fully automated spectrometric methods - DPPH, TEAC, FRAP, DMPD, Free Radicals and Blue CrO5. Absorption curves were measured and absorbance maxima were found. All methods were calibrated using the standard compounds Trolox® and/or gallic acid. Calibration curves were determined (relative standard deviation was within the range from 1.5 to 2.5 %). The obtained characteristics were compared and discussed. Moreover, the data obtained were applied to optimize and to automate all mentioned protocols. Automatic analyzer allowed us to analyse simultaneously larger set of samples, to decrease the measurement time, to eliminate the errors and to provide data of higher quality in comparison to manual analysis. The total time of analysis for one sample was decreased to 10 min for all six methods. In contrary, the total time of manual spectrometric determination was approximately 120 min. The obtained data provided good correlations between studied methods (R = 0.97 – 0.99).