Výzkumná skupina syntézy a chemické analýzy

@article{pmid26882954,

title = {Electrochemical sensing of etoposide using carbon quantum dot modified glassy carbon electrode},

author = {Hoai Viet Nguyen and Lukas Richtera and Amitava Moulick and Kledi Xhaxhiu and Jiri Kudr and Natalia Cernei and Hana Polanska and Zbynek Heger and Michal Masarik and Pavel Kopel and Marie Stiborova and Tomas Eckschlager and Vojtech Adam and Rene Kizek},

doi = {10.1039/c5an02476e},

issn = {1364-5528},

year  = {2016},

date = {2016-01-01},

journal = {Analyst},

volume = {141},

number = {9},

pages = {2665--2675},

abstract = {In this study, enhancement of the electrochemical signals of etoposide (ETO) measured by differential pulse voltammetry (DPV) by modifying a glassy carbon electrode (GCE) with carbon quantum dots (CQDs) is demonstrated. In comparison with a bare GCE, the modified GCE exhibited a higher sensitivity towards electrochemical detection of ETO. The lowest limit of detection was observed to be 5 nM ETO. Furthermore, scanning electron microscopy (SEM), fluorescence microscopy (FM), and electrochemical impedance spectroscopy (EIS) were employed for the further study of the working electrode surface after the modification with CQDs. Finally, the GCE modified with CQDs under optimized conditions was used to analyse real samples of ETO in the prostate cancer cell line PC3. After different incubation times (1, 3, 6, 9, 12, 18 and 24 h), these samples were then prepared prior to electrochemical detection by the GCE modified with CQDs. High performance liquid chromatography with an electrochemical detection method was employed to verify the results from the GCE modified with CQDs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27130152,

title = {A two-step protocol for isolation of influenza A (H7N7) virions and their RNA for PCR diagnostics based on modified paramagnetic particles},

author = {Petr Michalek and Simona Dostalova and Hana Buchtelova and Natalia Cernei and Ludmila Krejcova and David Hynek and Vedran Milosavljevic and Ana Maria Jimenez Jimenez and Pavel Kopel and Zbynek Heger and Vojtech Adam},

doi = {10.1002/elps.201600044},

issn = {1522-2683},

year  = {2016},

date = {2016-01-01},

journal = {Electrophoresis},

volume = {37},

number = {14},

pages = {2025--2035},

abstract = {Annual epidemics of influenza cause death of hundreds of thousands people and they also have a significant economic impact. Hence, a need for fast and cheap influenza diagnostic method is arising. The conventional methods for an isolation of the viruses are time-consuming and require expensive instrumentation as well as trained personnel. In this study, we modified the surface of nanomaghemite (γ-Fe2 O3 ) paramagnetic core with tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane and the resulting particles were utilized for the isolation of H7N7 influenza virions. Consequently, we designed γ-Fe2 O3 paramagnetic core modified with calcium tripolyphosphate which was employed for the isolation of viral nucleic acid after virion's lysis. Both of these procedures can be performed rapidly in less than 10 min and, in combination with the RT-PCR, the whole influenza detection can be shortened to few hours. Moreover, the whole protocol could be easily automated and/or miniaturized, and thus can serve as a basis for use in a lab-on-a-chip device. We assume that magnetic isolation is an exceptional procedure which can significantly accelerate the diagnostic possibilities of a broad spectrum of diseases.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27727290,

title = {The Zinc-Schiff Base-Novicidin Complex as a Potential Prostate Cancer Therapy},

author = {Vedran Milosavljevic and Yazan Haddad and Miguel Angel Merlos Rodrigo and Amitava Moulick and Hana Polanska and David Hynek and Zbynek Heger and Pavel Kopel and Vojtech Adam},

doi = {10.1371/journal.pone.0163983},

issn = {1932-6203},

year  = {2016},

date = {2016-01-01},

journal = {PLoS One},

volume = {11},

number = {10},

pages = {e0163983},

abstract = {Prostate cancer cells control energy metabolism by chelating intracellular zinc. Thus, zinc delivery has been a popular therapeutic approach for prostate cancer. Here, we propose the use of the membrane-penetrating peptide Novicidin connected to zinc-Schiff base as a carrier vehicle for the delivery of zinc to prostate cells. Mass spectrometry, electrochemistry and spectrophotometry confirmed the formation/stability of this complex and provided insight regarding the availability of zinc for complex interactions. This delivery system showed minor toxicity in normal PNT1A cells and high potency towards PC3 tumor cells. The complex preferentially penetrated PC3 tumor cells in contrast to confinement to the membranes of PNT1A. Furthermore, zinc uptake was confirmed in both cell lines. Molecular analysis was used to confirm the activation of zinc stress (e.g., ZnT-1) and apoptosis (e.g., CASP-1). Our results strongly suggest that the zinc-Schiff base-Novicidin complex has great potential as a novel anticancer drug.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Synthesis of carbon quantum dots for DNA labeling and its electrochemical, fluorescent and electrophoretic characterization},

author = {Vedran Milosavljevic and Hoai Viet Nguyen and Petr Michalek and Amitava Moulick and Pavel Kopel and Rene Kizek and Vojtech Adam},

doi = {https://doi.org/10.2478/s11696-014-0590-2},

year  = {2015},

date = {2015-12-30},

journal = {Chemical Papers},

volume = {69},

pages = {192–201},

abstract = {Nanoparticles as a progressively developing branch offer a tool for studying the interaction of carbon quantum dots (CQDs) with DNA. In this study, fluorescent CQDs were synthesized using citric acid covered with polyethylene glycol (PEG) as the source of carbon precursors. Furthermore, interactions between CQDs and DNA (double-stranded DNA and single-stranded DNA) were investigated by spectral methods, gel electrophoresis, and electrochemical analysis. Primarily, the fluorescent behavior of CQDs in the presence of DNA was monitored and major differences in the interaction of CQDs with tested single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) were observed at different amounts of CQDs (µg mL−1: 25, 50, 100, 250, 500). It was found that the interaction of ssDNA with CQDs had no significant influence on the CQDs fluorescence intensity measured at the excitation wavelengths of 280 nm, 350 nm, and 400 nm. However, in the presence of dsDNA, the fluorescence intensity of CQDs was significantly increased. Our results provide basic understanding of the interaction between CQDs and DNA. Such fabricated CQDs-DNA might be of great benefit for the emerging nanomaterials based biosensing methods.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Characterization of carbon dots covered with polyvinylpyrrolidone and polyethylene glycol},

author = {Kudr, Jiri and Richtera, Lukáš and Nejdl, Lukas and Milosavljevic, Vedran and Moravec, Zdenek and Wawrzak, Dorota and Kopel, Pavel and Ruttkay-Nedecky, Branislav and Adam, Vojtech and Kizek, Rene},

url = {http://www.electrochemsci.org/papers/vol10/101008243.pdf},

year  = {2015},

date = {2015-08-26},

journal = {International journal of electrochemical science},

volume = {10},

pages = {8243-8254},

abstract = {Luminescent carbon dots are new type of nanomaterial with possible applications in labelling and imaging due to their optoelectronic properties and their superior biocompatibility. The aim of this study was to synthetize two types of C-dots with different polymeric surface modification and to characterize them. Thermal method was used to prepare C-dots with surface stabilization with polyvinylpyrrolidone and polyethylene glycol. Several optical and electrochemical methods were used to characterize the particles. It was found that C-dots-PEG (3 ± 2 nm) possess stronger emission than C-dots-PVP (9 ± 3 nm) within the whole range of excitation wavelengths from 230 to 390 nm. Nevertheless in both cases the portion of C-dots created fluorescent micro-sized particles. Electrochemical impedance spectroscopy revealed that the electrode modified with both types of C-dots significantly increased resistance of bare glassy carbon electrode (C-dots-PVP 34-times and C-dots-PEG 141-times). In addition, it was found that pure polymers and C-dots also exhibit complex concentration dependent behaviour in Brdicka solution measured using hanging mercury drop electrode, whereas low amount added resulted in Co(II) peak (-1.3 V) shift and further resulted in three unresolved peak evolution between-0.5 and-0.9 V.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid26033737,

title = {Label-free bead-based metallothionein electrochemical immunosensor},

author = {Lukas Nejdl and Hoai Viet Nguyen and Lukas Richtera and Sona Krizkova and Roman Guran and Michal Masarik and David Hynek and Zbynek Heger and Karin Lundberg and Kristofer Erikson and Vojtech Adam and Rene Kizek},

doi = {10.1002/elps.201500069},

issn = {1522-2683},

year  = {2015},

date = {2015-08-01},

journal = {Electrophoresis},

volume = {36},

number = {16},

pages = {1894--1904},

abstract = {A novel microfluidic label-free bead-based metallothionein immunosensors was designed. To the surface of superparamagnetic agarose beads coated with protein A, polyclonal chicken IgY specifically recognizing metallothionein (MT) were immobilized via rabbit IgG. The Brdicka reaction was used for metallothionein detection in a microfluidic printed 3D chip. The assembled chip consisted of a single copper wire coated with a thin layer of amalgam as working electrode. Optimization of MT detection using designed microfluidic chip was performed in stationary system as well as in the flow arrangement at various flow rates (0-1800 μL/min). In stationary arrangement it is possible to detect MT concentrations up to 30 ng/mL level, flow arrangement allows reliable detection of even lower concentration (12.5 ng/mL). The assembled miniature flow chip was subsequently tested for the detection of MT elevated levels (at approx. level 100 μg/mL) in samples of patients with cancer. The stability of constructed device for metallothionein detection in flow arrangement was found to be several days without any maintenance needed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {The composites of graphene oxide with metal or semimetal nanoparticles and their effect on pathogenic microorganisms},

author = {Richtera, Lukáš and Chudobova, Dagmar and Dolezelikova, Kristyna and Kremplová, Monika and Milosavljevic, Vedran and Kopel, Pavel and Hynek, David and Adam, Vojtech and Kizek, Rene},

doi = {10.3390/ma8062994},

year  = {2015},

date = {2015-05-01},

journal = {Materials },

volume = {8},

issue = {6},

pages = {2994-3011},

abstract = {The present experiment describes a synthesis process of composites based on graphene oxide, which was tested as a carrier for composites of metal- or metalloid-based nanoparticles (Cu, Zn, Mn, Ag, AgP, Se) and subsequently examined as an antimicrobial agent for some bacterial strains (Staphylococcus aureus (S. aureus), methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). The composites were first applied at a concentration of 300 μM on all types of model organisms and their effect was observed by spectrophotometric analysis, which showed a decrease in absorbance values in comparison with the control, untreated strain. The most pronounced inhibition (87.4%) of S. aureus growth was observed after the application of graphene oxide composite with selenium nanoparticles compared to control. Moreover, the application of the composite with silver and silver phosphate nanoparticles showed the decrease of 68.8% and 56.8%, respectively. For all the tested composites, the observed antimicrobial effect was found in the range of 26% to 87.4%. Interestingly, the effects of the composites with selenium nanoparticles significantly differed in Gram-positive (G+) and Gram-negative (G−) bacteria. The effects of composites on bacterial cultures of S. aureus and MRSA, the representatives of G+ bacteria, increased with increasing concentrations. On the other hand, the effects of the same composites on G− bacteria E. coli was observed only in the highest applied concentration.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Synthesis and crystal structure of the first selenonyl bis(carboxylate) SeO2(O2CCH3)2},

author = {Richtera, Lukáš and Jancik, Vojtech and Barroso-Flores, Joaquin and Nykel, Petr and Touzin, Jiri and Taraba, Jan},

doi = {https://doi.org/10.1002/ejic.201500271},

year  = {2015},

date = {2015-05-01},

journal = {European Journal of Anorganic Chemistry},

volume = {18},

pages = {2923-2927},

abstract = {Analytically pure selenonyl bis(acetate) SeO2(O2CCH3)2 was prepared by the reaction of SeO3 with a stoichiometric amount of acetic anhydride in nitromethane; it crystallizes in the monoclinic P21/n space group with one molecule in the asymmetric unit and a = 5.2044(1) Å, b = 21.6580(5) Å, c = 6.7074(2) Å, and β = 93.628(2)°. The selenium atom binds to two oxo groups and two acetate anions in a distorted tetrahedral geometry. Analysis of the Hirschfeld surface indicated the presence of numerous C–H···O interactions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid32262379,

title = {Use of nucleic acids anchor system to reveal apoferritin modification by cadmium telluride nanoparticles},

author = {Jiri Kudr and Lukas Nejdl and Sylvie Skalickova and Michal Zurek and Vedran Milosavljevic and Renata Kensova and Branislav Ruttkay-Nedecky and Pavel Kopel and David Hynek and Marie Novotna and Vojtech Adam and Rene Kizek},

doi = {10.1039/c4tb01336k},

issn = {2050-7518},

year  = {2015},

date = {2015-03-01},

journal = {J Mater Chem B},

volume = {3},

number = {10},

pages = {2109--2118},

abstract = {The aim of this study was to synthesize cadmium telluride nanoparticles (CdTe NPs) modified apoferritin, and examine if apoferritin is able to accommodate CdTe NPs. Primarily, the thermostability of horse spleen apoferritin was tested and it's unfolding at 70 °C was observed. Cadmium telluride nanoparticles (CdTe NPs) were synthesized both within apoferritin protein cage and on its surface. The thermal treatment of apoferritin with CdTe NPs resulted in the aggregation of cores, which was indicated by changes in the absorption spectra and the shape of apoferritin tryptophan fluorescence. The apoferritin modified with CdTe NPs was additionally modified with gold nanoparticles and attached to magnetic particles via oligonucleotide using gold affinity to thiol group. This anchor system was used to separate the construct using external magnetic field and to analyse the molecules attached to apoferritin.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid25069433,

title = {3D-printed chip for detection of methicillin-resistant Staphylococcus aureus labeled with gold nanoparticles},

author = {Dagmar Chudobova and Kristyna Cihalova and Sylvie Skalickova and Jan Zitka and Miguel Angel Merlos Rodrigo and Vedran Milosavljevic and David Hynek and Pavel Kopel and Radek Vesely and Vojtech Adam and Rene Kizek},

doi = {10.1002/elps.201400321},

issn = {1522-2683},

year  = {2015},

date = {2015-02-01},

journal = {Electrophoresis},

volume = {36},

number = {3},

pages = {457--466},

abstract = {Methicillin-resistant Staphylococcus aureus (MRSA) is a dangerous pathogen occurring not only in hospitals but also in foodstuff. Currently, discussions on the issue of the increasing resistance, and timely and rapid diagnostic of resistance strains have become more frequent and sought. Therefore, the aim of this study was to design an effective platform for DNA isolation from different species of microorganisms as well as the amplification of mecA gene that encodes the resistance to β-lactam antibiotic formation and is contained in MRSA. For this purpose, we fabricated 3D-printed chip that was suitable for bacterial cultivation, DNA isolation, PCR, and detection of amplified gene using gold nanoparticle (AuNP) probes as an indicator of MRSA. Confirmation of the MRSA presence in the samples was based on a specific interaction between mecA gene with the AuNP probes and a colorimetric detection, which utilized the noncross-linking aggregation phenomenon of DNA-functionalized AuNPs. To test the whole system, we analyzed several real refractive indexes, in which two of them were positively scanned to find the presence of mecA gene. The aggregation of AuNP probes were reflected by 75% decrease of absorbance (λ = 530 nm) and change in AuNPs size from 3 ± 0.05 to 4 ± 0.05 nm (n = 5). We provide the one-step identification of mecA gene using the unique platform that employs the rapid, low-cost, and easy-to-use colorimetric method for MRSA detection in various samples. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid26695684,

title = {Exposure to 17β-Oestradiol Induces Oxidative Stress in the Non-Oestrogen Receptor Invertebrate Species Eisenia fetida},

author = {Zbynek Heger and Petr Michalek and Roman Guran and Barbora Havelkova and Marketa Kominkova and Natalia Cernei and Lukas Richtera and Miroslava Beklova and Vojtech Adam and Rene Kizek},

doi = {10.1371/journal.pone.0145426},

issn = {1932-6203},

year  = {2015},

date = {2015-01-01},

journal = {PLoS One},

volume = {10},

number = {12},

pages = {e0145426},

abstract = {BACKGROUND: The environmental impacts of various substances on all levels of organisms are under investigation. Among these substances, endocrine-disrupting compounds (EDCs) present a threat, although the environmental significance of these compounds remains largely unknown. To shed some light on this field, we assessed the effects of 17β-oestradiol on the growth, reproduction and formation of free radicals in Eisenia fetida.



METHODOLOGY/PRINCIPAL FINDINGS: Although the observed effects on growth and survival were relatively weak, a strong impact on reproduction was observed (50.70% inhibition in 100 μg/kg of E2). We further demonstrated that the exposure of the earthworm Eisenia fetida to a contaminant of emerging concern, 17β-oestradiol (E2), significantly affected the molecules involved in antioxidant defence. Exposure to E2 results in the production of reactive oxygen species (ROS) and the stimulation of antioxidant systems (metallothionein and reduced oxidized glutathione ratio) but not phytochelatins at both the mRNA and translated protein levels. Matrix-assisted laser desorption/ionization (MALDI)-imaging revealed the subcuticular bioaccumulation of oestradiol-3,4-quinone, altering the levels of local antioxidants in a time-dependent manner.



CONCLUSIONS/SIGNIFICANCE: The present study illustrates that although most invertebrates do not possess oestrogen receptors, these organisms can be affected by oestrogen hormones, likely reflecting free diffusion into the cellular microenvironment with subsequent degradation to molecules that undergo redox cycling, producing ROS, thereby increasing environmental contamination that also perilously affects keystone animals, forming lower trophic levels.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Behavior of UV sensitive zinc complexes revealed by using electrochemistry and spectroscopy.},

author = {Nejdl, Lukas and Richtera, Lukáš and Wawrzak, Dorota and Milosavljevic, Vedran and Kopel, Pavel and Kudr, Jiri and Ruttkay-Nedecky, Branislav and Adam, Vojtech and Kizek, Rene},

url = {http://www.electrochemsci.org/papers/vol10/100201696.pdf},

issn = {1452-3981},

year  = {2014},

date = {2014-12-30},

journal = {International journal of electrochemical science},

volume = {10},

issue = {2},

pages = {1696-1707},

abstract = {Synthesis, electrochemistry and spectroscopic techniques for five zinc(II) coordination complexes with a combination of tetradentate amines 1,4-bis(3-aminopropyl)piperazine (bapi), triethylenetetramine (tet) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (mtet) and thiodiacetic (tdaH2) or 1,3,5-benzenetricarboxylic acid (btcH3) are described. These complexes of general formulas [Zn2(L)2-tda)](ClO4)2 and [Zn3(L)3(-btc)](ClO4)3, where L = bapi, tet, mtet, have been studied in water solution. Their stability has been studied by electrochemical methods (cyclic voltammetry and differential pulse voltammetry) by using the hanging mercury drop electrode. There were also studied interactions of zinc(II) complexes with UV radiation assessed by fluorescence spectroscopy. It was found out that three complexes (Zn3(bapi)3-btc)](ClO4)3; Zn3(tet)3-btc)](ClO4)3; Zn3(mtet)3(-btc)](ClO4)3), after three minutes of UV irradiation became fluorescently active (Em = 400 nm) and fluorescence increased after each interval of UV irradiation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electrochemical Sensors and Biosensors for Influenza Detection - Literature Survey 2012-2013},

author = {Ludmila Krejcova and David Hynek and Petr Michalek and Vedran Milosavljevic and Pavel Kopel and Ondrej Zitka and Marie Konecna and Jindrich Kynicky and Vojtech Adam and Jaromir Hubalek and Rene Kizek},

url = {https://www.researchgate.net/publication/264052792_Electrochemical_Sensors_and_Biosensors_for_Influenza_Detection_-_Literature_Survey_2012-2013},

issn = {1452-3981},

year  = {2014},

date = {2014-07-01},

urldate = {2014-07-01},

journal = {International journal of electrochemical science},

volume = {9},

pages = {3440-3448},

abstract = {This review summarized published information in the area of electrochemical detection of influenza virus in 2012 - 2013. The attention was mainly paid to summarize the news in the field of sensors and biosensors for influenza detection. Further, the impedance and quartz crystal microbalance sensing devices are also discussed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid25476270,

title = {Application of CdTe/ZnSe quantum dots in in vitro imaging of chicken tissue and embryo},

author = {Amitava Moulick and Iva Blazkova and Vedran Milosavljevic and Zdenka Fohlerova and Jaromir Hubalek and Pavel Kopel and Marketa Vaculovicova and Vojtech Adam and Rene Kizek},

doi = {10.1111/php.12398},

issn = {1751-1097},

journal = {Photochem Photobiol},

volume = {91},

number = {2},

pages = {417--423},

abstract = {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. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}