Laboratoř elektrochemie

@article{pmid30805185b,

title = {Zinc phosphate-based nanoparticles as a novel antibacterial agent:  study on rats after dietary exposure},

author = {Pavel Horky and Sylvie Skalickova and Lenka Urbankova and Daria Baholet and Silvia Kociova and Zuzana Bytesnikova and Eliska Kabourkova and Zuzana Lackova and Natalia Cernei and Milica Gagic and Vedran Milosavljevic and Vendula Smolikova and Eva Vaclavkova and Pavel Nevrkla and Pavel Knot and Olga Krystofova and David Hynek and Pavel Kopel and Jiri Skladanka and Vojtech Adam and Kristyna Smerkova},

doi = {10.1186/s40104-019-0319-8},

issn = {1674-9782},

year  = {2019},

date = {2019-01-01},

journal = {J Anim Sci Biotechnol},

volume = {10},

pages = {17},

abstract = {BACKGROUND: Development of new nanomaterials that inhibit or kill bacteria is an important and timely research topic. For example, financial losses due to infectious diseases, such as diarrhea, are a major concern in livestock productions around the world. Antimicrobial nanoparticles (NPs) represent a promising alternative to antibiotics and may lower antibiotic use and consequently spread of antibiotic resistance traits among bacteria, including pathogens.



RESULTS: Four formulations of zinc nanoparticles (ZnA, ZnB, ZnC, and ZnD) based on phosphates with spherical (ZnA, ZnB) or irregular (ZnC, ZnD) morphology were prepared. The highest  inhibitory effect of our NPs was observed against  (inhibitory concentration values, IC, ranged from 0.5 to 1.6 mmol/L) followed by  (IC 0.8-1.5 mmol/L). In contrast, methicillin resistant  (IC 1.2-4.7 mmol/L) was least affected and this was similar to inhibitory patterns of commercial ZnO-based NPs and ZnO. After the successful  testing, the in vivo study with rats based on dietary supplementation with zinc NPs was conducted. Four groups of rats were treated by 2,000 mg Zn/kg diet of ZnA, ZnB, ZnC, and ZnD, for comparison two groups were supplemented by 2,000 mg Zn/kg diet of ZnO-N and ZnO, and one group (control) was fed only by basal diet. The significantly higher ( < 0.05) Zn level in liver and kidney of all treated groups was found, nevertheless Zn NPs did not greatly influence antioxidant status of rats. However, the total aerobic and coliform bacterial population in rat feces significantly decreased ( < 0.05) in all zinc groups after 30 d of the treatment. Furthermore, when compared to the ZnO group, ZnA and ZnC nanoparticles reduced coliforms significantly more ( < 0.05).



CONCLUSIONS: Our results demonstrate that phosphate-based zinc nanoparticles have the potential to act as antibiotic agents.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid31226356,

title = {Nanoparticle-drug conjugates treating bacterial infections},

author = {Pavlina Jelinkova and Aninda Mazumdar and Vishma Pratap Sur and Silvia Kociova and Kristyna Dolezelikova and Ana Maria Jimenez Jimenez and Zuzana Koudelkova and Pawan Kumar Mishra and Kristyna Smerkova and Zbynek Heger and Marketa Vaculovicova and Amitava Moulick and Vojtech Adam},

doi = {10.1016/j.jconrel.2019.06.013},

issn = {1873-4995},

year  = {2019},

date = {2019-01-01},

journal = {J Control Release},

volume = {307},

pages = {166--185},

abstract = {The ever increasing scenario of bacterial resistance against commonly available antibiotics is becoming a global threat of major concern, which necessitates the development of new strategies to overcome this hurdle. Conjugation of nanoparticles (NPs) with antimicrobial moieties, such as antibiotics, peptides or different biomolecules, has been one of the successful techniques in targeting antibiotic resistance. This review mainly focusses on the possible nanoparticle-drug conjugates with their activity against pathogenic bacterial infections. Nanoparticles play an array of roles, e.g. as a carrier, synergistically acting agent and as theranostic agent, henceforth facilitates the efficacy of therapy. Moreover, this review elaborates the studies with reported nanoparticles-drug conjugates that include their possible synthesis methodologies and applications. In most of the cases, the nanoparticles were found to increase the permeability of bacterial cell membrane, which enables higher uptake of antibiotics inside the bacterial cells which in return showed better effects. Even the conjugates were found to efficiently kill the antibiotic-resistant strains. Since several limitations are exerted by the biological systems, there is an urge for the advancement of nanoparticle-drug conjugates for better proficiency.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Trace level voltammetric determination of Zn(II) in selected nutrition related samples by bismuth-oxychloride-multiwalled carbon nanotube composite based electrode},

author = {Sandra Petrović and Valéria Guzsvány and Nikola Ranković and Jelena Beljin and Srđan Rončević and Božo Dalmacija and Amir M. Ashrafi and Zoltán Kónya and Ivan Švancara and Karel Vytřas},

doi = {https://doi.org/10.1016/j.microc.2018.12.053},

issn = {0026-265X},

year  = {2018},

date = {2018-12-27},

journal = {Microchemical Journal},

volume = {146},

pages = {178-186},

abstract = {Bismuth-oxychloride-multiwalled carbon nanotube composite material was applied as surface modifier of glassy carbon electrode (BiOCl-MWCNT/GCE) for rapid and reliable trace level determination of Zn(II) in selected foodstuffs. The method development encompasses the optimization of electrode preparation including the transmission electron microscopic study of the modifier suspension, selection of the supporting electrolyte pH, the adjustment of the operation parameters of the SW-ASV measurements and the investigation of matrix effects. By the BiOCl-MWCNT/GCE recorded calibration curve showed an excellent linearity towards Zn reoxidation peak intensity in the concentration range from 2.50 to 80.0 μg L−1 with the calculated LOD of 0.75 μg L−1 which was associated with 120 s accumulation time and accumulation potential −1.40 V vs SCE in acetate buffer pH 4.5. A satisfactory repeatability expressed as relative standard deviation of 4.8% was obtained in the case of 10.0 μg L−1 Zn(II) in model solution. The Zn(II) reoxidation signal from BiOCl-MWCNT/GCE received by the optimized SW-ASV method was compared with those recorded with bare, classical bismuth-film, multiwalled carbon nanotubes and by in situ made advanced bismuth-film-MWCNTs working electrodes. The applicability of the proposed BiOCl-MWCNT/GCE based method was corroborated via measuring the target analyte in two nutrition related real samples: in a dietary supplement and in a brewer's yeast sample. Comparative flame atomic absorption spectrometric measurements verified the obtained results in the case of yeast sample.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Review—Electrochemical Sensors and Biosensors for Determination of Mercury Ions},

author = {Amirmansoor Ashrafi and Zuzana Koudelkova and Eliska Sedlackova and Lukáš Richtera and Vojtech Adam },

url = {https://iopscience.iop.org/article/10.1149/2.0381816jes},

year  = {2018},

date = {2018-12-11},

urldate = {2018-12-11},

journal = {Journal of The Electrochemical Society},

volume = {165},

number = {16},

abstract = {Due to its toxicity, mercury determination is of great importance in human health and pollution monitoring. The mercury compounds can be released into our environment in several ways. Therefore, so many analytical procedures have been developed for detection of mercury. In this review, the analytical methods used for determination of mercury ions have been reported highlighting the electrochemical methods and in particular electrochemical biosensors. The electrochemical biosensors for determination of mercury were categorized into three groups including DNA-based, enzyme-based and whole-cell based biosensors and the mechanisms of the function of each group were described. The advantages and challenges of each class of biosensors are discussed in this review.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid30264566,

title = {Real-Time Visualization of Cell Membrane Damage Using Gadolinium-Schiff Base Complex-Doped Quantum Dots},

author = {Amitava Moulick and Zbynek Heger and Vedran Milosavljevic and Lukas Richtera and Joaquin Barroso-Flores and Miguel Angel Merlos Rodrigo and Hana Buchtelova and Robert Podgajny and David Hynek and Pavel Kopel and Vojtech Adam},

doi = {10.1021/acsami.8b15868},

issn = {1944-8252},

year  = {2018},

date = {2018-10-01},

journal = {ACS Appl Mater Interfaces},

volume = {10},

number = {42},

pages = {35859--35868},

abstract = {Despite the importance of cell membranes for maintenance of integrity of cellular structures, there is still a lack of methods that allow simple real-time visualization of their damage. Herein, we describe gadolinium-Schiff base-doped quantum dots (GdQDs)-based probes for a fast facile spatial labeling of membrane injuries. We found that GdQDs preferentially interact through electron-rich and hydrophobic residues with a specific sequence motif of NHE-RF2 scaffold protein, exposed upon membrane damage. Such interaction results in a fast formation of intensively fluorescent droplets with a higher resolution and in a much shorter time compared to immunofluorescence using organic dye. GdQDs have high stability, brightness, and considerable cytocompatibility, which enable their use in long-term experiments in living cultures. To the best of our knowledge, this is the first report, demonstrating a method allowing real-time monitoring of membrane damage and recovery without any special requirements for instrumentation. Because of intensive brightness and simple signal pattern, GdQDs allow easy examination of interactions between cellular membranes and cell-penetrating peptides or cytostatic drugs. We anticipate that the simple and flexible method will also facilitate the studies dealing with host-pathogen interactions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid30264566b,

title = {Real-Time Visualization of Cell Membrane Damage Using Gadolinium-Schiff Base Complex-Doped Quantum Dots},

author = {Amitava Moulick and Zbynek Heger and Vedran Milosavljevic and Lukas Richtera and Joaquin Barroso-Flores and Miguel Angel Merlos Rodrigo and Hana Buchtelova and Robert Podgajny and David Hynek and Pavel Kopel and Vojtech Adam},

doi = {10.1021/acsami.8b15868},

issn = {1944-8252},

year  = {2018},

date = {2018-10-01},

journal = {ACS Appl Mater Interfaces},

volume = {10},

number = {42},

pages = {35859--35868},

abstract = {Despite the importance of cell membranes for maintenance of integrity of cellular structures, there is still a lack of methods that allow simple real-time visualization of their damage. Herein, we describe gadolinium-Schiff base-doped quantum dots (GdQDs)-based probes for a fast facile spatial labeling of membrane injuries. We found that GdQDs preferentially interact through electron-rich and hydrophobic residues with a specific sequence motif of NHE-RF2 scaffold protein, exposed upon membrane damage. Such interaction results in a fast formation of intensively fluorescent droplets with a higher resolution and in a much shorter time compared to immunofluorescence using organic dye. GdQDs have high stability, brightness, and considerable cytocompatibility, which enable their use in long-term experiments in living cultures. To the best of our knowledge, this is the first report, demonstrating a method allowing real-time monitoring of membrane damage and recovery without any special requirements for instrumentation. Because of intensive brightness and simple signal pattern, GdQDs allow easy examination of interactions between cellular membranes and cell-penetrating peptides or cytostatic drugs. We anticipate that the simple and flexible method will also facilitate the studies dealing with host-pathogen interactions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Determination of chromium(vi) by anodic stripping voltammetry using a silver-plated glassy carbon electrode},

author = {Stojanović, Z. and Koudelková, Z. and Sedláčková, E. and Hynek, D. and Richtera, L. and Adam, V.},

doi = {https://doi.org/10.1039/C8AY01047A},

year  = {2018},

date = {2018-05-11},

journal = {Analytical Methods},

issue = {24},

abstract = {In this work, differential pulse anodic stripping voltammetry (DP-ASV) for the determination of trace amounts of hexavalent chromium (Cr(VI)) at a silver plated glassy carbon electrode (Ag plated-GCE) is described in detail. A Ag film was prepared by in situ plating of silver on the glassy carbon electrode surface. Several solution conditions and instrumental parameters influencing the electroanalytical response of the Ag plated-GCE were examined and optimized for the determination of Cr(VI). Under the optimized conditions, the calibration curve obtained in CH3COOH/NH3 (aq) medium at pH 5.9 was linear over the wide concentration range of 0.35–40 μM Cr(VI). The present method shows a low limit of detection of 0.10 μM. After evaluation of effects from possible interferences, the proposed method was successfully applied for the quantification of Cr(VI) in real water samples, with satisfactory recovery (97–105%). This method is useful for the determination of chromium in drinking water and achieves sensitivity capable of detecting the limits set by the World Health Organization (WHO).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Development and characterisation of furcellaran-gelatin films containing SeNPs and AgNPs that have antimicrobial activity},

author = {Ewelina Jamróz and Pavel Kopel and Lesław Juszczak and Agnieszka Kawecka and Zuzana Bytesnikova and Vedran Milosavljević and Mateusz Kucharek and Małgorzata Makarewicz and Vojtech Adam

},

doi = {https://doi.org/10.1016/j.foodhyd.2018.04.028},

issn = {0268-005X},

year  = {2018},

date = {2018-04-21},

journal = {Food Hydrocolloids},

volume = {83},

abstract = {Binary-blend films of furcellaran and gelatin (FUR/GEL) and FUR/GEL composite films reinforced with selenium nanoparticles (SeNPs) or silver nanoparticles (AgNPs) were prepared using a solution casting method. The effects of SeNPs and AgNPs on the physical, mechanical, structural, antibacterial properties of the furcellaran/gelatin-based films were examined. It follows from these examinations that the incorporation of SeNPs and AgNPs leads to an increase in thickness, water content, modulus of elasticity, elongation at break, and antimicrobial activity when higher parameters a*, b*, and ΔE are observed in nanocomposite films with AgNPs compared to those enriched with SeNPs. Compared with control film, the addition of nanoparticles significantly decreased solubility and swelling degree. Films containing SeNPs show greater antimicrobial activity against Escherichia coli, Staphylococcus aureus and multi resistant Staphylococcus aureus than films containing AgNPs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29673366,

title = {Improving cytocompatibility of CdTe quantum dots by Schiff-base-coordinated lanthanides surface doping},

author = {Hana Buchtelova and Vladislav Strmiska and Zuzana Skubalova and Simona Dostalova and Petr Michalek and Sona Krizkova and David Hynek and Lukas Kalina and Lukas Richtera and Amitava Moulick and Vojtech Adam and Zbynek Heger},

doi = {10.1186/s12951-018-0369-7},

issn = {1477-3155},

year  = {2018},

date = {2018-04-01},

journal = {J Nanobiotechnology},

volume = {16},

number = {1},

pages = {43},

abstract = {BACKGROUND: Suitable fluorophores are the core of fluorescence imaging. Among the most exciting, yet controversial, labels are quantum dots (QDs) with their unique optical and chemical properties, but also considerable toxicity. This hinders QDs applicability in living systems. Surface chemistry has a profound impact on biological behavior of QDs. This study describes a two-step synthesis of QDs formed by CdTe core doped with Schiff base ligand for lanthanides [Ln (Yb, Tb and Gd)] as novel cytocompatible fluorophores.



RESULTS: Microwave-assisted synthesis resulted in water-soluble nanocrystals with high colloidal and fluorescence stability with quantum yields of 40.9-58.0%. Despite induction of endocytosis and cytoplasm accumulation of Yb- and TbQDs, surface doping resulted in significant enhancement in cytocompatibility when compared to the un-doped CdTe QDs. Furthermore, only negligible antimigratory properties without triggering formation of reactive oxygen species were found, particularly for TbQDs. Ln-doped QDs did not cause observable hemolysis, adsorbed only a low degree of plasma proteins onto their surface and did not possess significant genotoxicity. To validate the applicability of Ln-doped QDs for in vitro visualization of receptor status of living cells, we performed a site-directed conjugation of antibodies towards immuno-labeling of clinically relevant target-human norepinephrine transporter (hNET), over-expressed in neuroendocrine tumors like neuroblastoma. Immuno-performance of modified TbQDs was successfully tested in distinct types of cells varying in hNET expression and also in neuroblastoma cells with hNET expression up-regulated by vorinostat.



CONCLUSION: For the first time we show that Ln-doping of CdTe QDs can significantly alleviate their cytotoxic effects. The obtained results imply great potential of Ln-doped QDs as cytocompatible and stable fluorophores for various bio-labeling applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Bipolar membrane electrodialysis assisted pH correction of milk whey},

author = {Arthur Merkel and Amir M. Ashrafi and Jiří Ečer},

doi = {https://doi.org/10.1016/j.memsci.2018.03.035},

issn = {0376-7388},

year  = {2018},

date = {2018-03-16},

journal = {Journal of Membrane Science},

volume = {555},

pages = {185-196},

abstract = {The neutralization of milk whey after the electrodialysis (ED) is usually carried out by direct addition of NaOH or KOH solution. However, the addition of these solutions results in an increase in total solids and ash content of the whey sample. In this work, electrodialysis with the bipolar membrane (EDBM) was examined to neutralize the desalinated whey after ED. First, ED was used to desalinate the nanofiltrated whey (NFW). Three milk whey samples differing in demineralization rate in ED were subjected to the EDBM. Two configurations of EDBM were applied to increase the pH of the milk whey samples. When the samples which had been demineralized first with conventional ED, were submitted in EDBM the pH increased to the desired values. However, the pH of NFW sample only increased to the values less than 6. The changes in pH, total solids, ash content, and minerals profile of various samples after EDBM were investigated. It was figured out that the increase in pH was not accompanied by any significant increase in total solids and ash content of the samples. The mechanisms of ion transport during EDBM for either cations or anions were investigated. The cations were mainly transported by diffusion in developed configurations of EDBM while anions were transported either with diffusion or migration depending on the type of milk whey sample. With increasing the demineralization rate of the whey in ED the diffusional transport of species in EDBM reduces due to the decrease in ion content of the whey. Two configurations of EDBM were compared in terms of fouling on the BM surface, electrodialysis capacity, and energy consumption.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Europium and terbium Schiff base peptide complexes as potential antimicrobial agents against Salmonella typhimurium and Pseudomonas aeruginosa},

author = {Jindrich Kynicky and Vedran Milosavljevic and Pavlina Jelinkova and Yazan Haddad and Miguel Angel Merlos Rodrigo and Hana Buchtelova and Zuzana Bytesnikova and Martin Brtnicky and Lukas Richtera and Pavel Kopel and Vojtech Adam},

doi = {https://doi.org/10.1007/s11696-018-0400-3},

year  = {2018},

date = {2018-01-25},

urldate = {2018-01-25},

journal = {Chemical Papers},

abstract = {Eu(III) and Tb(III) Schiff base complexes are applicable in various fields such as sensing, assays, screening protocols in vitro, and imaging studies in vitro or in vivo. Fluorescent europium and terbium complexes and their interaction with cell penetrating peptide (KKKRKC) can represent an excellent key for understanding pathway of peptide transportation though cell membrane and the application of Schiff base complexes as potential antibacterial drugs. The Schiff base–metal complexes and its conjugates with peptide were tested for their antibacterial activity against Pseudomonas aeruginosa and Salmonella typhimurium. Schiff base–metal complexes conjugated with peptide show minor toxicity in normal human PNT1A cells and high antibacterial activity against P. aeruginosa and S. typhimurium, where IC50 down to 125.9 and/or 36.1 µM were found for P. aeruginosa and S. typhimurium, respectively. Our results strongly suggest that Schiff base–metal complexes conjugated with peptide have great potential to be developed into highly effective antibacterial drug.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29936287,

title = {Effect of arsenic (III and V) on oxidative stress parameters in resistant and susceptible Staphylococcus aureus},

author = {Pavlina Jelinkova and Radek Vesely and Kristyna Cihalova and Dagmar Hegerova and Hanadi Abd Alrahman Ali Ananbeh and Lukas Richtera and Kristyna Smerkova and Martin Brtnicky and Jindrich Kynicky and Amitava Moulick and Vojtech Adam},

doi = {10.1016/j.envres.2018.06.024},

issn = {1096-0953},

year  = {2018},

date = {2018-01-01},

journal = {Environ Res},

volume = {166},

pages = {394--401},

abstract = {The presented study deals with the observation of properties of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in the toxic arsenic environment and influence of arsenic on antioxidant capacity. Two forms of arsenic (As(III), As(V)) with different concentrations were used for induction of the oxidative stress in tested strains. Microbiological methods showed that the growth inhibition of MSSA was higher than that of MRSA in presence of both arsenic ions. As(III) showed 24% and 33% higher anti-microbial effects than As(V) against MSSA and MRSA respectively. A similar result was found also in the experiment of reduction of biofilm-formation. By using spectrophotometry, it was revealed that As(III) induced higher antioxidant production in both bacterial cultures. Methicillin-susceptible S. aureus produced an app. 50 mg equivalent of gallic acid (GAE/1 mg of protein) and MRSA produced an app. 15 mg of GAE/1 mg of protein. The productions of metallothionein in MSSA and MRSA were decreased up to 62.41% and 55.84% respectively in presence of As ions. Reduction of As(III) and As(V) concentrations leads to a decrease in antioxidant production and increased the formation of metallothionein. All of these changes in the results were found to be significant statistically. Taken together, these experiments proved that in comparison with MSSA, MRSA is less susceptible not only to the antimicrobial effects of antibiotics but also against effects caused by metalloids, as arsenic. Thus, it can be stated that MRSA abounds with complex defensive mechanisms, which may in the future constitute significant problem in the efficiency of antibiotics alternatives as metal ions or nanoparticles.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid30086240,

title = {Functional Analysis of Novicidin Peptide: Coordinated Delivery System for Zinc via Schiff Base Ligand},

author = {Vedran Milosavljevic and Yazan Haddad and Amitava Moulick and Hana Buchtelova and Roman Guran and Tomas Pospisil and Kamila Stokowa-Sołtys and Zbynek Heger and Lukas Richtera and Pavel Kopel and Vojtech Adam},

doi = {10.1021/acs.bioconjchem.8b00370},

issn = {1520-4812},

year  = {2018},

date = {2018-01-01},

journal = {Bioconjug Chem},

volume = {29},

number = {9},

pages = {2954--2969},

abstract = {Novicidin (NVC), is a membrane-penetrating peptide, which forms a stable complex with Zn-Schiff base with interesting antitumor selectivity. We studied NVC derivatives to determine functional roles of key amino acids in toxicity, helicity, and binding of the Zn-Schiff base complex. Trimmed derivatives highlighted the role of peptide length and helicity in toxicity and membrane penetration. The removal of Lys from position 1 and 2 strongly increases the ability to disrupt the membranes. The trimming of the N-terminal residues significantly increases the stability of peptide helicity enhancing penetrating properties. Gly residue derivatives undermined a role of peptide bending in membrane penetration and toxicity. After the substitution of the central Gly derivatives with Ile or Lys, the peptides retained toxicity. These results illustrate the minor role of central helix bending in NVC toxicity. Binding-site-peptide derivatives identified His residue as the sole Zn-Schiff base binding site and eliminated the role of other aromatic residues.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid30349337,

title = {Novel vancomycin-peptide conjugate as potent antibacterial agent against vancomycin-resistant },

author = {Pavlina Jelinkova and Zbynek Splichal and Ana Maria Jimenez Jimenez and Yazan Haddad and Aninda Mazumdar and Vishma Pratap Sur and Vedran Milosavljevic and Pavel Kopel and Hana Buchtelova and Roman Guran and Ondrej Zitka and Lukas Richtera and Dagmar Hegerova and Zbynek Heger and Amitava Moulick and Vojtech Adam},

doi = {10.2147/IDR.S160975},

issn = {1178-6973},

year  = {2018},

date = {2018-01-01},

journal = {Infect Drug Resist},

volume = {11},

pages = {1807--1817},

abstract = {BACKGROUND: Increase in vancomycin (Van)-resistant bacterial strains including vancomycin-resistant  (VRSA) and lack of new effective antibiotics have become a formidable health problem.



MATERIALS AND METHODS: We designed a new conjugate composed of Van and a peptide Hecate (Hec; Van/Hec), and its potential antimicrobial activity was evaluated.



RESULTS: Results from disk diffusion test, time-kill assay, determination of minimum inhibitory concentration (MIC), microscopy, and comet assay showed strong antimicrobial effects of Van/Hec against wild-type, methicillin-resistant  (MRSA) and VRSA. Microscopy revealed that the exposure to Van/Hec results in disruption of bacterial cell integrity in all tested strains, which was not observed in case of Van or Hec alone.



CONCLUSION: Overall, we showed that the preparation of conjugates from antibiotics and biologically active peptides could help us to overcome the limitation of the use of antibiotic in the treatment of infections caused by multidrug-resistant bacteria.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28963959,

title = {Kinetic analysis of human metallothionein and CdTe quantum dot complexes using fluorescence and voltammetry techniques},

author = {Ewelina Guszpit and Ludmila Krejčová and Soňa Křížková and Marta Kepinska and Lukáš Richtera and Pavel Kopel and Vojtěch Adam and Halina Milnerowicz},

doi = {10.1016/j.colsurfb.2017.09.033},

issn = {1873-4367},

year  = {2017},

date = {2017-12-01},

journal = {Colloids Surf B Biointerfaces},

volume = {160},

pages = {381--389},

abstract = {Thanks to quantum dots' (QDs) properties, they can be used as selective and sensitive biomarkers in molecular imaging. In a previous paper, we confirmed the possibility of interaction between mercaptosuccinic acid-capped cadmium telluride QDs (MSA-CdTe) and human metallothionein (MT). The aim of this study was to expand on our previous research with an evaluation of the stability of the formed complexes between human MT and four CdTe compounds of the following sizes: 3.4nm (blue QDs), 3.8nm (green QDs), 4.5nm (yellow QDs), and 5.2nm (red QDs). Complexes were evaluated over time using fluorescence intensity and differential pulse voltammetry. Differences between the voltammograms obtained for standard solutions and for CdTe+MT show that complexes were formed. An increase in fluorescence intensity was observed for blue (Δ%≈40 for t=1→120min) and red (Δ%≈30 for t=1→120min) CdTe-MT complexes than CdTe alone, whereas green and yellow CdTe-MT complexes had a lower fluorescence intensity than CdTe alone. A stronger time dependence of the mercaptosuccinic acid (MSA) peak height on the timeline and differences in the MSA peak shape (in CdTe, and CdTe+MT complexes) were also observed by voltammetry. Authors noticed a decrease in the Cat2 signal of the red and green CdTe+MT complexes at the time of conjugation. Our results reveal that the size of QDs has an impact on the interaction between CdTe and human MT, as well as on the stability of complexes formed during these interactions. The bioconjugates' stability was also found to depend on the time of interaction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dual-color quantum dots-based simultaneous detection of HPV-HIV co-infection},

author = {Ana Maria Jimenez Jimenez and Amitava Moulick and Lukas Richtera and Ludmila Krejcova and Lukas Kalina and Rahul Datta and Marketa Svobodova and David Hynek and Michal Masarik and Zbynek Heger and Vojtech Adam},

doi = {https://doi.org/10.1016/j.snb.2017.11.074},

issn = {0925-4005},

year  = {2017},

date = {2017-11-16},

journal = {Sensors and Actuators B: Chemical},

volume = {258},

abstract = {Human papillomavirus (HPV) and human immunodeficiency virus (HIV) are closely related infections; both diseases are mutually reinforcing due to the co-infection effects, which increase their clinical and epidemiological implications, raising urgent public health concerns. In the present study, a nano-system was developed for simultaneous detection of HPV and HIV targeting E6-HPV16 and Gag-HIV genes respectively. The target sequences from the samples of the patients suffering from head and neck cancer were isolated by magnetic glass particles (MGPs) and subsequently were hybridized with a mixture of the complementary probes attached to cadmium telluride quantum dots (CdTe QDs). Finally, the specific and successful binding was determined by an easy fluorescence analyses and was corroborated by PCR and electrochemistry. Red and green CdTe QDs were used for the dual-color detection of HPV and HIV respectively. Our nano-system can be applied as a proficient tool for the identification of HPV, HIV or both diseases simultaneously, getting a successful and high sensitivity system of detection.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28641203,

title = {Current trends in electrochemical sensing and biosensing of DNA methylation},

author = {Ludmila Krejcova and Lukas Richtera and David Hynek and Jan Labuda and Vojtech Adam},

doi = {10.1016/j.bios.2017.06.004},

issn = {1873-4235},

year  = {2017},

date = {2017-11-01},

journal = {Biosens Bioelectron},

volume = {97},

pages = {384--399},

abstract = {DNA methylation plays an important role in physiological and pathological processes. Several genetic diseases and most malignancies tend to be associated with aberrant DNA methylation. Among other analytical methods, electrochemical approaches have been successfully employed for characterisation of DNA methylation patterns that are essential for the diagnosis and treatment of particular diseases. This article discusses current trends in the electrochemical sensing and biosensing of DNA methylation. Particularly, it provides an overview of applied electrode materials, electrode modifications and biorecognition elements applications with an emphasis on strategies that form the core DNA methylation detection approaches. The three main strategies as (i) bisulfite treatment, (ii) cleavage by restriction endonucleases, and (iii) immuno/affinity reaction were described in greater detail. Additionally, the availability of the reviewed platforms for early cancer diagnosis and the approval of methylation inhibitors for anticancer therapy were discussed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {pH-Responsive Hybrid Organic–Inorganic Ruthenium Nanoparticles for Controlled Release of Doxorubicin},

author = {Hana Buchtelova and Vladislav Strmiska and Simona Dostalova and Petr Michalek and Sona Krizkova and Pavel Kopel and David Hynek and Lukas Richtera and Vojtech Adam and Zbynek Heger},

doi = {https://doi.org/10.1002/ppsc.201700289},

year  = {2017},

date = {2017-10-24},

journal = {Particle & Particle Systems Characterization},

volume = {34},

issue = {11},

abstract = {The current study aims at preparing biocompatible hybrid organic–inorganic ruthenium core–shell nanostructures (RuNPs) coated with polyvinylpyrrolidone (PVP) and polyoxyethylene stearate (POES). Thereafter, the core/shell RuNPs are loaded with doxorubicin (to form RuPDox) with a loading efficiency > 60%. RuPDox possesses exceptional stability and pH-responsive release kinetics with approx. 50% release of doxorubicin at up to 1 h exposure to an acidic endosomal environment. The cytotoxic effects of RuPDox are tested in vitro against breast cancer (MDA-MB-231), ovarian cancer (A2780), and neuroblastoma (UKF-NB-4) cells. Notably, although RuNPs have slight cytotoxicity only, RuPDox causes a synergistic enhancement of cytotoxicity when compared to free doxorubicin. Significant increase in free radicals formation, enhanced activity of executioner caspases 3/7, and higher expression of p53 and metallothionein is further identified due to the RuPDox treatment. Single-cell gel electrophoresis reveals no additional contribution of RuNPs to genotoxicity of doxorubicin. Moreover, RuPDox promotes significantly increased stability of doxorubicin in human plasma and pronounced hemocompatibility assayed on human red blood cells. The results imply a high potential of biocompatible hybrid RuNPs with PVP-POES shell as versatile nanoplatforms to enhance the efficiency of cancer treatment.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electrochemical Characterization of the Interaction of Multiwalled Carbon Nanotubes with Doxorubicin},

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

doi = {https://doi.org/10.1080/00032719.2017.1284860},

year  = {2017},

date = {2017-09-19},

journal = {Analytical Letters},

volume = {50},

issue = {14},

pages = {2335-2341},

abstract = {It has been suggested that multiwalled carbon nanotubes (MWCNTs) interacting with pharmaceutics may be introduced into the body as nanocarriers. To deliver the anticancer drugs, covalent or noncovalent functionalization of MWCNTs is required. In this study, the influence of oxidation on MWCNTs in the interaction with chemotherapeutic drug, doxorubicin, was characterized. The binding of doxorubicin with MWCNTs decreased rapidly with the increasing oxidation period with sulfuric acid. However, with nitric acid, the interaction increased initially and slowly decreased with time. The best results were obtained for sulfuric and nitric acid following 1 and 3 h of oxidation, respectively. The results show that sulfuric acid provided more favorable interaction for MWCNTs with doxorubicin than nitric acid.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28792450,

title = {Determination of Zinc, Cadmium, Lead, Copper and Silver Using a Carbon Paste Electrode and a Screen Printed Electrode Modified with Chromium(III) Oxide},

author = {Zuzana Koudelkova and Tomas Syrovy and Pavlina Ambrozova and Zdenek Moravec and Lubomir Kubac and David Hynek and Lukas Richtera and Vojtech Adam},

doi = {10.3390/s17081832},

issn = {1424-8220},

year  = {2017},

date = {2017-08-01},

journal = {Sensors (Basel)},

volume = {17},

number = {8},

abstract = {In this study, the preparation and electrochemical application of a chromium(III) oxide modified carbon paste electrode (Cr-CPE) and a screen printed electrode (SPE), made from the same material and optimized for the simple, cheap and sensitive simultaneous determination of zinc, cadmium, lead, copper and the detection of silver ions, is described. The limits of detection and quantification were 25 and 80 µg·L for Zn(II), 3 and 10 µg·L for Cd(II), 3 and 10 µg·L for Pb(II), 3 and 10 µg·L for Cu(II), and 3 and 10 µg·L for Ag(I), respectively. Furthermore, this promising modification was transferred to the screen-printed electrode. The limits of detection for the simultaneous determination of zinc, cadmium, copper and lead on the screen printed electrodes were found to be 350 µg·L for Zn(II), 25 µg·L for Cd(II), 3 µg·L for Pb(II) and 3 µg·L for Cu(II). Practical usability for the simultaneous detection of these heavy metal ions by the Cr-CPE was also demonstrated in the analyses of wastewaters.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28850089,

title = {Magnetic Nanoparticles: From Design and Synthesis to Real World Applications},

author = {Jiri Kudr and Yazan Haddad and Lukas Richtera and Zbynek Heger and Mirko Cernak and Vojtech Adam and Ondrej Zitka},

doi = {10.3390/nano7090243},

issn = {2079-4991},

year  = {2017},

date = {2017-08-01},

journal = {Nanomaterials (Basel)},

volume = {7},

number = {9},

abstract = {The increasing number of scientific publications focusing on magnetic materials indicates growing interest in the broader scientific community. Substantial progress was made in the synthesis of magnetic materials of desired size, morphology, chemical composition, and surface chemistry. Physical and chemical stability of magnetic materials is acquired by the coating. Moreover, surface layers of polymers, silica, biomolecules, etc. can be designed to obtain affinity to target molecules. The combination of the ability to respond to the external magnetic field and the rich possibilities of coatings makes magnetic materials universal tool for magnetic separations of small molecules, biomolecules and cells. In the biomedical field, magnetic particles and magnetic composites are utilized as the drug carriers, as contrast agents for magnetic resonance imaging (MRI), and in magnetic hyperthermia. However, the multifunctional magnetic particles enabling the diagnosis and therapy at the same time are emerging. The presented review article summarizes the findings regarding the design and synthesis of magnetic materials focused on biomedical applications. We highlight the utilization of magnetic materials in separation/preconcentration of various molecules and cells, and their use in diagnosis and therapy.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28527356,

title = {Exceptional release kinetics and cytotoxic selectivity of oxidised MWCNTs double-functionalised with doxorubicin and prostate-homing peptide},

author = {Vedran Milosavljevic and Ludmila Krejcova and Roman Guran and Hana Buchtelova and Dorota Wawrzak and Lukas Richtera and Zbynek Heger and Pavel Kopel and Vojtech Adam},

doi = {10.1016/j.colsurfb.2017.05.008},

issn = {1873-4367},

year  = {2017},

date = {2017-08-01},

journal = {Colloids Surf B Biointerfaces},

volume = {156},

pages = {123--132},

abstract = {Multiwall carbon nanotubes (MWCNTs) are among the frequently studied carbon materials, particularly because of their physical and chemical properties and high potential for application in materials chemistry, industry, and medicine. MWCNTs are very promising as transporters of bioactive molecules because of their π electrons and large surface area, which can be easily modified, mostly by the application of inorganic acids for the introduction of carboxylic moieties on the surface. In the present study, we designed an oxidised MWCNTs (oMWCNTs) transporter for the targeted delivery of doxorubicin (Dox). The modification of oMWCNTs with prostate-homing peptide (SMSIARL) promotes increased cytotoxicity for prostate cancer cells. Using advanced analytical techniques, we studied the loading efficiency, stability, and release kinetics of Dox from a oMWCNTs-Dox-Pep nanoconstruct. We show that pH strictly drives Dox release, and imitating the pH of intracellular acidic compartments, 60% of Dox is released from oMWCNTs-Dox-Pep, while in plasma conditions, only a 14% release of Dox was found during 24h. The nanoconstruct displayed no cytotoxicity in non-malignant prostate cells (PNT1A), while in metastatic prostate cancer cells (LNCaP), the cytotoxic effects were close to the cytotoxicity of free Dox. This indicates that peptide modification promotes interactions with malignant cells, resulting in efficient internalisation into the intracellular region. Overall, we show that oMWCNTs are exceptional platforms for simple and stable non-covalent modification with bioactive molecules.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28811028,

title = {Advanced nanotechnologies in avian influenza: Current status and future trends - A review},

author = {Amitava Moulick and Lukas Richtera and Vedran Milosavljevic and Natalia Cernei and Yazan Haddad and Ondrej Zitka and Pavel Kopel and Zbynek Heger and Vojtech Adam},

doi = {10.1016/j.aca.2017.06.045},

issn = {1873-4324},

year  = {2017},

date = {2017-08-01},

journal = {Anal Chim Acta},

volume = {983},

pages = {42--53},

abstract = {In the last decade, the control of avian influenza virus has experienced many difficulties, which have caused major global agricultural problems that have also led to public health consequences. Conventional biochemical methods are not sufficient to detect and control agricultural pathogens in the field due to the growing demand for food and subsidiary products; thus, studies aiming to develop potent alternatives to conventional biochemical methods are urgently needed. In this review, emerging detection systems, their applicability to diagnostics, and their therapeutic possibilities in view of nanotechnology are discussed. Nanotechnology-based sensors are used for rapid, sensitive and cost-effective diagnostics of agricultural pathogens. The application of different nanomaterials promotes interactions between these materials and the virus, which enables researchers to construct portable electroanalytical biosensing analyser that should effectively detect the influenza virus. The present review will provide insights into the guidelines for future experiments to develop better techniques to detect and control influenza viruses.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28465190,

title = {Size-related cytotoxicological aspects of polyvinylpyrrolidone-capped platinum nanoparticles},

author = {Hana Buchtelova and Simona Dostalova and Petr Michalek and Sona Krizkova and Vladislav Strmiska and Pavel Kopel and David Hynek and Lukas Richtera and Andrea Ridoskova and Pavlina Adam and Jindrich Kynicky and Martin Brtnicky and Zbynek Heger and Vojtech Adam},

doi = {10.1016/j.fct.2017.04.043},

issn = {1873-6351},

year  = {2017},

date = {2017-07-01},

journal = {Food Chem Toxicol},

volume = {105},

pages = {337--346},

abstract = {The nanotechnological concept is based on size-dependent properties of particles in the 1-100 nm range. Nevertheless, the connection between their size and effect is still not clear. Thus, we focused on reductive colloidal synthesis, characterization and biological testing of Pt nanoparticles (PtNPs) capped with biocompatible polymer polyvinylpyrrolidone (PVP). Synthesized PtNPs were of 3 different primary sizes (approx. ∼10; ∼14 and > 20 nm) and demonstrated exceptional haemocompatibility. In vitro treatment of three different types of malignant cells (prostate - LNCaP, breast - MDA-MB-231 and neuroblastoma - GI-ME-N) revealed that even marginal differences in PtNPs diameter resulted in changes in their cytotoxicity. The highest cytotoxicity was observed using the smallest PtNPs-10, where 24IC was lower (3.1-6.2 μg/mL) than for cisplatin (8.1-19.8 μg/mL). In contrast to MDA-MB-231 and LNCaP cells, in GI-ME-N cells PtNPs caused noticeable changes in their cellular structure without influencing their viability. Post-exposure analyses revealed that PtNPs-29 and PtNPs-40 were capable of forming considerably higher amount of reactive oxygen species with consequent stimulation of expression of metallothionein (MT1/2 and MT3), at both mRNA and protein level. Overall, our pilot study demonstrates that in the nanoscaled world even the smallest differences can have crucial biological effect.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28395246,

title = {Electrochemical and optical study of metallothionein interactions with prion proteins},

author = {Alzbeta Cardova and Pavlina Adam and Stefano Mariani and Lukas Richtera and Zbynek Heger and Jan Labuda and Maria Minunni and Vojtech Adam},

doi = {10.1016/j.jpba.2017.03.044},

issn = {1873-264X},

year  = {2017},

date = {2017-06-01},

journal = {J Pharm Biomed Anal},

volume = {140},

pages = {355--361},

abstract = {The prion protein (PrP) can be structurally shifted to its PrP isoform causing a wide range of neurodegenerative diseases, which are currently incurable. There is an evidence that metallothioneins (MTs), and especially MT-3, are associated with neurodegenerative diseases. PrP and MTs play pivotal roles in maintaining metal homeostasis; therefore, it is conceivable that each of them has its own significance in prion diseases. In this paper, we study the nature of interactions between PrP, MT, and copper ions, Cu(II), using the method of differential pulse voltammetry (DPV) coupled with adsorptive transfer stripping technique (AdTS). Electrochemical properties of PrP itself and its interactions with both the Cu(II) ions and MTs have been found. Based on the results obtained, we hypothesised the formation of the complex in molar ratio 2:1 (PrP:MT). Surface plasmon resonance imaging (SPRi) was used as a control reference assay to further confirm results obtained by the electrochemical approach, such as the specific interactions between PrP and MT-3.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28213325,

title = {Carbon dots based FRET for the detection of DNA damage},

author = {Jiri Kudr and Lukas Richtera and Kledi Xhaxhiu and David Hynek and Zbynek Heger and Ondrej Zitka and Vojtech Adam},

doi = {10.1016/j.bios.2017.01.067},

issn = {1873-4235},

year  = {2017},

date = {2017-06-01},

journal = {Biosens Bioelectron},

volume = {92},

pages = {133--139},

abstract = {Here, we aimed our attention at the synthesis of carbon dots (C-dots) with the ability to interact with DNA to suggest an approach for the detection of DNA damage. Primarily, C-dots modified with amine moieties were synthesized using the one-step microwave pyrolysis of citric acid in the presence of diethylenetriamine. The C-dots showed strong photoluminescence with a quantum yield of 4%. In addition, the C-dots (2.8±0.8nm) possessed a good colloidal stability and exhibited a positive surface charge (ζ=36mV) at a neutral pH. An interaction study of the C-dots and the DNA fragment of λ bacteriophage was performed, and the DNA binding resulted in changes to the photoluminescent and absorption properties of the C-dots. A binding of the C-dots to DNA was also observed as a change to DNA electrophoretic mobility and a decreased ability to intercalate ethidium bromide (EtBr). Moreover, the Förster (or fluorescence) resonance energy transfer (FRET) between the C-dots and EtBr was studied, in which the C-dots serve as an excitation energy donor and the EtBr serves as an acceptor. When DNA was damaged using ultraviolet (UV) radiation (λ=254nm) and hydroxyl radicals, the intensity of the emitted photoluminescence at 612nm significantly decreased. The concept was proved on analysis of the genomic DNA from PC-3 cells and DNA isolated from melanoma tissues.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Determination of the Fineness of Medieval Coins—Evaluation of Methods in a Case Study of a Medieval Pfennig},

author = {Kučera, L. and Richtera, L. and Zmrzlý, M. and Jarošová, M. and Kučerová, P. and Bednář, P.},

doi = {https://doi.org/10.1111/arcm.12313},

year  = {2017},

date = {2017-05-12},

journal = {Archaeometry},

volume = {60},

issue = {2},

abstract = {The original fineness of coins is very important information that can help us to understand the commercial situation in a wide historical context. This paper deals with a comparison of analytical methods suitable for the evaluation of the actual and original fineness of coins based on a detailed case study of a medieval coin sample. Both non-destructive (i.e., scanning electron microscopy/energy-dispersive X-ray spectroscopy, X-ray fluorescence, atomic force microscopy and hydrostatic weighing) and destructive (i.e., inductively coupled plasma – mass spectrometry and the Volhard titration method) techniques were used. The original fineness can be also deduced from knowledge of the internal structure of the coin (limited miscibility of copper and silver). A new analytical method based on a combination of a micrograph of the metallographic cross-section with consequent image analysis was developed for determination of the original fineness. The proposed approach is relatively simple and provides reliable values. Sample heterogeneity and its impact on the determination of fineness are also discussed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28101932,

title = {Amino Acid Profiling of Zinc Resistant Prostate Cancer Cell Lines: Associations With Cancer Progression},

author = {Monika Kratochvilova and Martina Raudenska and Zbynek Heger and Lukas Richtera and Natalia Cernei and Vojtech Adam and Petr Babula and Marie Novakova and Michal Masarik and Jaromir Gumulec},

doi = {10.1002/pros.23304},

issn = {1097-0045},

year  = {2017},

date = {2017-05-01},

journal = {Prostate},

volume = {77},

number = {6},

pages = {604--616},

abstract = {BACKGROUND: Failure in intracellular zinc accumulation is a key process in prostate carcinogenesis. Nevertheless, epidemiological studies of zinc administration have provided contradicting results. In order to examine the impact of the artificial intracellular increase of zinc(II) ions on prostate cancer metabolism, PNT1A, 22Rv1, and PC-3 prostatic cell lines-depicting different stages of cancer progression-and their zinc-resistant counterparts were used. To determine "benign" and "malignant" metabolic profiles, amino acid patterns, gene expression, and antioxidant capacity of these cell lines were assessed.



METHODS: Amino acid profiles were examined using an ion-exchange liquid chromatography. Intracellular zinc content was measured by atomic absorption spectrometry. Metallothionein was quantified using differential pulse voltammetry. The content of reduced glutathione was determined using high performance liquid chromatography coupled with an electrochemical detector. Cellular antioxidant capacity was determined by the ABTS test and gene expression analysis was performed by qRT-PCR.



RESULTS AND CONCLUSIONS: Long-term zinc treatment was shown to reroute cell metabolism from benign to more malignant type. Long-term application of high concentration of zinc(II) significantly enhanced cisplatin resistance, invasiveness, cellular antioxidant capacity, synthesis of glutathione, and expression of treatment resistance- and stemness-associated genes (SOX2, POU5F1, BIRC5). Tumorous cell lines universally displayed high accumulation of aspartate and sarcosine and depletion of essential amino acids. Increased aspartate/threonine, aspartate/methionine, and sarcosine/serine ratios were associated with cancer phenotype with high levels of sensitivity and specificity. Prostate 77: 604-616, 2017. © 2017 Wiley Periodicals, Inc.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Real-time monitoring of the UV-induced formation of quantum dots on a milliliter, microliter, and nanoliter scale},

author = {Lukas Nejdl and Jan Zitka and Filip Mravec and Vedran Milosavljevic and Ondrej Zitka and Pavel Kopel and Vojtech Adam and Marketa Vaculovicova},

doi = {10.1007/s00604-017-2149-8},

year  = {2017},

date = {2017-03-03},

journal = {Microchimica Acta},

pages = {1489–1497},

abstract = {The authors report on a systematic study on the low-cost, low-temperature, and fast synthesis of water soluble quantum dots (QDs) stabilized by mercaptosuccinic acid by UV irradiation. The effects of UV irradiation (at 254 nm and 250 nm) and temperature on the precursors (Cd:Se, Cd:Te, Cd, Zn:S, Zn:Se and Zn) are described. Best results are achieved with a mixture of precursors containing cadmium, selenium and MSA where a 10-min irradiation with 254-nm light gives CdSe QDs with a quantum yield of 13.5%. The authors also describe the preparation and monitoring of the formation of QDs in sub-mg, sub-μg and sub-ng quantities, the smallest concentration being 258 pg in volume of 4 nL. The growth of the QDs can be monitored in real time by absorption, fluorescence and dynamic light scattering. The solutions of the particles also are characterized by fluorescence correlation spectroscopy and detected by LED-induced fluorescence. The preparation of such QDs by UV radiation is simple, easily controllable, and inexpensive. Conceivably, it can be integrated with lab-on-chip, micro total analysis systems or other instrumentation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28287470,

title = {The Application of Curve Fitting on the Voltammograms of Various Isoforms of Metallothioneins-Metal Complexes},

author = {Miguel Angel Merlos Rodrigo and Jorge Molina-López and Ana Maria Jimenez Jimenez and Elena Planells Del Pozo and Pavlina Adam and Tomas Eckschlager and Ondrej Zitka and Lukas Richtera and Vojtech Adam},

doi = {10.3390/ijms18030610},

issn = {1422-0067},

year  = {2017},

date = {2017-03-01},

journal = {Int J Mol Sci},

volume = {18},

number = {3},

abstract = {The translation of metallothioneins (MTs) is one of the defense strategies by which organisms protect themselves from metal-induced toxicity. MTs belong to a family of proteins comprising MT-1, MT-2, MT-3, and MT-4 classes, with multiple isoforms within each class. The main aim of this study was to determine the behavior of MT in dependence on various externally modelled environments, using electrochemistry. In our study, the mass distribution of MTs was characterized using MALDI-TOF. After that, adsorptive transfer stripping technique with differential pulse voltammetry was selected for optimization of electrochemical detection of MTs with regard to accumulation time and pH effects. Our results show that utilization of 0.5 M NaCl, pH 6.4, as the supporting electrolyte provides a highly complicated fingerprint, showing a number of non-resolved voltammograms. Hence, we further resolved the voltammograms exhibiting the broad and overlapping signals using curve fitting. The separated signals were assigned to the electrochemical responses of several MT complexes with zinc(II), cadmium(II), and copper(II), respectively. Our results show that electrochemistry could serve as a great tool for metalloproteomic applications to determine the ratio of metal ion bonds within the target protein structure, however, it provides highly complicated signals, which require further resolution using a proper statistical method, such as curve fitting.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27894780,

title = {Antibody-free detection of infectious bacteria using quantum dots-based barcode assay},

author = {Kristyna Cihalova and Dagmar Hegerova and Ana Maria Jimenez and Vedran Milosavljevic and Jiri Kudr and Sylvie Skalickova and David Hynek and Pavel Kopel and Marketa Vaculovicova and Vojtech Adam},

doi = {10.1016/j.jpba.2016.10.025},

issn = {1873-264X},

year  = {2017},

date = {2017-02-01},

journal = {J Pharm Biomed Anal},

volume = {134},

pages = {325--332},

abstract = {Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Klebsiella pneumoniae are the most representative bacteria causing infectious diseases. Due to the increased application of antibiotics, the bacterial resistance is growing causing severe complications. Therefore, a sensitive determination of these pathogens is crucial for effective treatment. The aim of this study was to design an effective method for multiplex detection of Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Klebsiella pneumoniae taking advantage from properties of magnetic particles as well as fluorescent nanoparticles (quantum dots). The method was able to detect as low concentrations of bacteria as 10 CFU/mL using the bacteria-specific genes (fnbA, mecA and wcaG).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28392686,

title = {Apoferritin as an ubiquitous nanocarrier with excellent shelf life},

author = {Simona Dostalova and Katerina Vasickova and David Hynek and Sona Krizkova and Lukas Richtera and Marketa Vaculovicova and Tomas Eckschlager and Marie Stiborova and Zbynek Heger and Vojtech Adam},

doi = {10.2147/IJN.S130267},

issn = {1178-2013},

year  = {2017},

date = {2017-01-01},

journal = {Int J Nanomedicine},

volume = {12},

pages = {2265--2278},

abstract = {Due to many adverse effects of conventional chemotherapy, novel methods of targeting drugs to cancer cells are being investigated. Nanosize carriers are a suitable platform for this specific delivery. Herein, we evaluated the long-term stability of the naturally found protein nanocarrier apoferritin (Apo) with encapsulated doxorubicin (Dox). The encapsulation was performed using Apo's ability to disassemble reversibly into its subunits at low pH (2.7) and reassemble in neutral pH (7.2), physically entrapping drug molecules in its cavity (creating ApoDox). In this study, ApoDox was prepared in water and phosphate-buffered saline and stored for 12 weeks in various conditions (-20°C, 4°C, 20°C, and 37°C in dark, and 4°C and 20°C under ambient light). During storage, a very low amount of prematurely released drug molecules were detected (maximum of 7.5% for ApoDox prepared in PBS and 4.4% for ApoDox prepared in water). Fourier-transform infrared spectra revealed no significant differences in any of the samples after storage. Most of the ApoDox prepared in phosphate-buffered saline and ApoDox prepared in water and stored at -20°C formed very large aggregates (up to 487% of original size). Only ApoDox prepared in water and stored at 4°C showed no significant increase in size or shape. Although this storage caused slower internalization to LNCaP prostate cancer cells, ApoDox (2.5 μM of Dox) still retained its ability to inhibit completely the growth of 1.5×10 LNCaP cells after 72 hours. ApoDox stored at 20°C and 37°C in water was not able to deliver Dox inside the nucleus, and thus did not inhibit the growth of the LNCaP cells. Overall, our study demonstrates that ApoDox has very good stability over the course of 12 weeks when stored properly (at 4°C), and is thus suitable for use as a nanocarrier in the specific delivery of anticancer drugs to patients.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27984119,

title = {Comparative study on toxicity of extracellularly biosynthesized and laboratory synthesized CdTe quantum dots},

author = {Marketa Kominkova and Vedran Milosavljevic and Petr Vitek and Hana Polanska and Kristyna Cihalova and Simona Dostalova and Veronika Hynstova and Roman Guran and Pavel Kopel and Lukas Richtera and Michal Masarik and Martin Brtnicky and Jindrich Kynicky and Ondrej Zitka and Vojtech Adam},

doi = {10.1016/j.jbiotec.2016.10.024},

issn = {1873-4863},

year  = {2017},

date = {2017-01-01},

journal = {J Biotechnol},

volume = {241},

pages = {193--200},

abstract = {Nanobiosynthesis belongs to the most recent methods for synthesis of nanoparticles. This type of synthesis provides many advantages including the uniformity in particle shape and size. The biosynthesis has also a significant advantage regarding chemical properties of the obtained particles. In this study, we characterized the basic properties and composition of quantum dots (QDs), obtained by the extracellular biosynthesis by Escherichia coli. Furthermore, the toxicity of the biosynthesized QDs was compared to QDs prepared by microwave synthesis. The obtained results revealed the presence of cyan CdTe QDs after removal of substantial amounts of organic compounds, which stabilized the nanoparticle surface. QDs toxicity was evaluated using three cell lines Human Foreskin Fibroblast (HFF), Human Prostate Cancer cells (PC-3) and Breast Cancer cells (MCF-7) and the MTT assay. The test revealed differences in the toxicity between variants of QDs, varying about 10% in the HFF and 30% in the MCF-7 cell lines. The toxicity of the biosynthesized QDs to the PC-3 cell lines was about 35% lower in comparison with the QDs prepared by microwave synthesis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27943679,

title = {Alternative Synthesis Route of Biocompatible Polyvinylpyrrolidone Nanoparticles and Their Effect on Pathogenic Microorganisms},

author = {Vedran Milosavljevic and Pavlina Jelinkova and Ana Maria Jimenez Jimenez and Amitava Moulick and Yazan Haddad and Hana Buchtelova and Sona Krizkova and Zbynek Heger and Lukas Kalina and Lukas Richtera and Pavel Kopel and Vojtech Adam},

doi = {10.1021/acs.molpharmaceut.6b00807},

issn = {1543-8392},

year  = {2017},

date = {2017-01-01},

journal = {Mol Pharm},

volume = {14},

number = {1},

pages = {221--233},

abstract = {Herein we describe a novel alternative synthesis route of polyvinylpyrrolidone nanoparticles using salting-out method at a temperature close to polyvinylpyrrolidone decomposition. At elevated temperatures, the stability of polyvinylpyrrolidone decreases and the opening of pyrrolidone ring fractions occurs. This leads to cross-linking process, where separate units of polyvinylpyrrolidone interact among themselves and rearrange to form nanoparticles. The formation/stability of these nanoparticles was confirmed by transmission electron microscopy, X-ray photoelectron spectroscopy, mass spectrometry, infrared spectroscopy, and spectrophotometry. The obtained nanoparticles possess exceptional biocompatibility. No toxicity and genotoxicity was found in normal human prostate epithelium cells (PNT1A) together with their high hemocompatibility. The antimicrobial effects of polyvinylpyrrolidone nanoparticles were tested on bacterial strains isolated from the wounds of patients suffering from hard-to-heal infections. Molecular analysis (qPCR) confirmed that the treatment can induce the regulation of stress-related survival genes. Our results strongly suggest that the polyvinylpyrrolidone nanoparticles have great potential to be developed into a novel antibacterial compound.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27356860,

title = {Selenium nanoparticles as a nutritional supplement},

author = {Sylvie Skalickova and Vedran Milosavljevic and Kristyna Cihalova and Pavel Horky and Lukas Richtera and Vojtech Adam},

doi = {10.1016/j.nut.2016.05.001},

issn = {1873-1244},

year  = {2017},

date = {2017-01-01},

journal = {Nutrition},

volume = {33},

pages = {83--90},

abstract = {Selenium is an essential trace element in the diet, required for maintenance of health and growth; however, its toxicity could cause serious damage depending on dose and chemical form. Selenium nanoparticles (SeNPs) represent what we believe to be a novel prospect for nutritional supplementation because of their lower toxicity and ability to gradually release selenium after ingestion. In this review, we discuss various forms and types of SeNPs, as well as the way they are synthesized. We also discuss absorption and bioavailability of nanoparticles within the organism. SeNPs demonstrate anticancer and antimicrobial properties that may contribute to human health, not only as dietary supplements, but also as therapeutic agents.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28243089,

title = {Using CdTe/ZnSe core/shell quantum dots to detect DNA and damage to DNA},

author = {Amitava Moulick and Vedran Milosavljevic and Jana Vlachova and Robert Podgajny and David Hynek and Pavel Kopel and Vojtech Adam},

doi = {10.2147/IJN.S121840},

issn = {1178-2013},

year  = {2017},

date = {2017-01-01},

journal = {Int J Nanomedicine},

volume = {12},

pages = {1277--1291},

abstract = {CdTe/ZnSe core/shell quantum dot (QD), one of the strongest and most highly luminescent nanoparticles, was directly synthesized in an aqueous medium to study its individual interactions with important nucleobases (adenine, guanine, cytosine, and thymine) in detail. The results obtained from the optical analyses indicated that the interactions of the QDs with different nucleobases were different, which reflected in different fluorescent emission maxima and intensities. The difference in the interaction was found due to the different chemical behavior and different sizes of the formed nanoconjugates. An electrochemical study also confirmed that the purines and pyrimidines show different interactions with the core/shell QDs. Based on these phenomena, a novel QD-based method is developed to detect the presence of the DNA, damage to DNA, and mutation. The QDs were successfully applied very easily to detect any change in the sequence (mutation) of DNA. The QDs also showed their ability to detect DNAs directly from the extracts of human cancer (PC3) and normal (PNT1A) cells (detection limit of 500 pM of DNA), which indicates the possibilities to use this easy assay technique to confirm the presence of living organisms in extreme environments.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27825623,

title = {Fully automated two-step assay for detection of metallothionein through magnetic isolation using functionalized γ-FeO particles},

author = {Miguel Angel Merlos Rodrigo and Ludmila Krejcova and Jiri Kudr and Natalia Cernei and Pavel Kopel and Lukas Richtera and Amitava Moulick and David Hynek and Vojtech Adam and Marie Stiborova and Tomas Eckschlager and Zbynek Heger and Ondrej Zitka},

doi = {10.1016/j.jchromb.2016.10.018},

issn = {1873-376X},

year  = {2016},

date = {2016-12-01},

journal = {J Chromatogr B Analyt Technol Biomed Life Sci},

volume = {1039},

pages = {17--27},

abstract = {Metallothioneins (MTs) are involved in heavy metal detoxification in a wide range of living organisms. Currently, it is well known that MTs play substantial role in many pathophysiological processes, including carcinogenesis, and they can serve as diagnostic biomarkers. In order to increase the applicability of MT in cancer diagnostics, an easy-to-use and rapid method for its detection is required. Hence, the aim of this study was to develop a fully automated and high-throughput assay for the estimation of MT levels. Here, we report the optimal conditions for the isolation of MTs from rabbit liver and their characterization using MALDI-TOF MS. In addition, we described a two-step assay, which started with an isolation of the protein using functionalized paramagnetic particles and finished with their electrochemical analysis. The designed easy-to-use, cost-effective, error-free and fully automated procedure for the isolation of MT coupled with a simple analytical detection method can provide a prototype for the construction of a diagnostic instrument, which would be appropriate for the monitoring of carcinogenesis or MT-related chemoresistance of tumors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27435634,

title = {Electrochemical speciation analysis for simultaneous determination of Cr(iii) and Cr(vi) using an activated glassy carbon electrode},

author = {Lukas Richtera and Hoai Viet Nguyen and David Hynek and Jiri Kudr and Vojtech Adam},

doi = {10.1039/c6an00983b},

issn = {1364-5528},

year  = {2016},

date = {2016-10-01},

journal = {Analyst},

volume = {141},

number = {19},

pages = {5577--5585},

abstract = {In this study, the enhancement of electrochemical signals of Cr(iii) and Cr(vi) by using an activated glassy carbon electrode (GCE) measured by differential pulse voltammetry (DPV) is demonstrated. The activated GCE exhibited higher sensitivity for detection of Cr(iii) and Cr(vi) compared with the bare GCE. By using the activated GCE, the limit of detection decreased 15.3 times (from 0.230 to 0.015 μM) in the case of Cr(iii) determination and 75 times (from 9.000 to 0.120 μM) in the case of Cr(vi) determination. Moreover, a simultaneous speciation analysis of Cr(iii) and Cr(vi) using the activated GCE was presented. Scanning electron microscopy, elemental mapping, and electrochemical impedance spectroscopy were employed for investigation of the surface of the activated GCE. Finally, the influence of different ions (Na(+), K(+), NH4(+), SO4(2-), NO3(-), and Cl(-) in the form of Na2SO4, NaNO3, NH4Cl, and KCl salts) on the speciation signals of Cr(iii) and Cr(vi) in a mixture of the two Cr oxidation states was investigated. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Gold nanoparticles-modified nanomaghemite and quantum dots-based hybridization assay for detection of HPV},

author = {Ana Maria Jimenez Jimenez and Miguel Angel Merlos Rodrigo and Vedran Milosavljevic and Sona Krizkova and Pavel Kopel and Zbynek Heger and Vojtech Adam

},

doi = {https://doi.org/10.1016/j.snb.2016.08.091},

issn = {0925-4005},

year  = {2016},

date = {2016-09-08},

urldate = {2016-09-08},

journal = {Sensors and Actuators B: Chemical},

volume = {240},

pages = {503-510},

abstract = {Head and neck squamous cell carcinomas (HNSCC) are malignant tumors originating from the upper aerodigestive tract. The environmental pollution, high alcohol consumption and smoking are associated with this type of cancer, as well as the human papillomavirus (HPV), which is often involved in the carcinogenesis and significantly correlates with the cancer prognosis. In recent decades, the number of techniques based on diagnostic of HPV using nanotechnologies including nanoparticles and their surface modification has been developed. Herein, we describe specific biosensing system for detection of HPV. The biosensor employs gold-coated nanoparticles-coated superparamagnetic nanomaghemite (AuMNPs) covered with thiolated oligodeoxyribonucleotides complementary to DNA sequence of E6 HPV-16 oncogene. Successful binding of viral ssDNA was recognized by anti-dsDNA antibodies labeled with HWRGWVC peptide-modified-CdTe quantum dots. The recognition and detection parts were characterized and the specificity was tested using HIV, influenza and HBV-specific oligonucleotides. As a proof-of-concept, system was employed for a detection of HPV-16 E6 presence in DNA obtained by eight subjects with histologically confirmed HNSCC. The obtained results were successfully verified using polymerase chain reaction (PCR). The developed system offers a cheap alternative to conventional PCR with a comparable sensitivity and versatility.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27219717,

title = {Site-Directed Conjugation of Antibodies to Apoferritin Nanocarrier for Targeted Drug Delivery to Prostate Cancer Cells},

author = {Simona Dostalova and Tereza Cerna and David Hynek and Zuzana Koudelkova and Tomas Vaculovic and Pavel Kopel and Jan Hrabeta and Zbynek Heger and Marketa Vaculovicova and Tomas Eckschlager and Marie Stiborova and Vojtech Adam},

doi = {10.1021/acsami.6b04286},

issn = {1944-8252},

year  = {2016},

date = {2016-06-01},

journal = {ACS Appl Mater Interfaces},

volume = {8},

number = {23},

pages = {14430--14441},

abstract = {Herein, we describe a novel approach for targeting of ubiquitous protein apoferritin (APO)-encapsulating doxorubicin (DOX) to prostate cancer using antibodies against prostate-specific membrane antigen (PSMA). The conjugation of anti-PSMA antibodies and APO was carried out using HWRGWVC heptapeptide, providing their site-directed orientation. The prostate-cancer-targeted and nontargeted nanocarriers were tested using LNCaP and HUVEC cell lines. A total of 90% of LNCaP cells died after treatment with DOX (0.25 μM) or DOX in nontargeted and prostate-cancer-targeted APO, proving that the encapsulated DOX toxicity for LNCaP cells remained the same. Free DOX showed higher toxicity for nonmalignant cells, whereas the toxicity was lower after treatment with the same dosage of APO-encapsulated DOX (APODOX) and even more in prostate-cancer-targeted APODOX. Hemolytic assay revealed exceptional hemocompatibility of the entire nanocarrier. The APO encapsulation mechanism ensures applicability using a wide variety of chemotherapeutic drugs, and the presented surface modification enables targeting to various tumors. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27164078,

title = {Specific Magnetic Isolation of E6 HPV16 Modified Magnetizable Particles Coupled with PCR and Electrochemical Detection},

author = {Ana Maria Jimenez Jimenez and Branislav Ruttkay-Nedecky and Simona Dostalova and Ludmila Krejcova and Petr Michalek and Lukas Richtera and Vojtech Adam},

doi = {10.3390/ijms17050585},

issn = {1422-0067},

year  = {2016},

date = {2016-05-01},

journal = {Int J Mol Sci},

volume = {17},

number = {5},

abstract = {The majority of carcinomas that were developed due to the infection with human papillomavirus (HPV) are caused by high-risk HPV types, HPV16 and HPV18. These HPV types contain the E6 and E7 oncogenes, so the fast detection of these oncogenes is an important point to avoid the development of cancer. Many different HPV tests are available to detect the presence of HPV in biological samples. The aim of this study was to design a fast and low cost method for HPV identification employing magnetic isolation, polymerase chain reaction (PCR) and electrochemical detection. These assays were developed to detect the interactions between E6-HPV16 oncogene and magnetizable particles (MPs) using commercial Dynabeads M-280 Streptavidin particles and laboratory-synthesized "homemade" particles called MANs (MAN-37, MAN-127 and MAN-164). The yields of PCR amplification of E6-HPV16 oncogene bound on the particles and after the elution from the particles were compared. A highest yield of E6-HPV16 DNA isolation was obtained with both MPs particles commercial M-280 Streptavidin and MAN-37 due to reducing of the interferents compared with the standard PCR method. A biosensor employing the isolation of E6-HPV16 oncogene with MPs particles followed by its electrochemical detection can be a very effective technique for HPV identification, providing simple, sensitive and cost-effective analysis. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {3D printed stratospheric probe as a platform for determination of DNA damage based on carbon quantum dots/DNA complex fluorescence increase},

author = {Zbynek Heger and Jan Zitka and Lukas Nejdl and Amitava Moulick and Vedran Milosavljevic and Pavel Kopel and Ondrej Zavodsky and Jakub Kapus and Libor Lenza and Milan Rezka and Vojtech Adam and Rene Kizek},

doi = {10.1007/s00706-016-1705-y},

year  = {2016},

date = {2016-03-10},

urldate = {2016-03-10},

journal = {Monatshefte für Chemie - Chemical Monthly},

pages = {873–880},

abstract = {We present a utilization of carbon quantum dots (CQDs), passivated with polyethylene glycol as a fluorescent recognition probe for DNA damage. Synthesized CQDs were characterized in detail, using optical and electrochemical methods. Further, fluorescent behavior of CQDs was monitored in the presence of genomic DNA, isolated from Staphylococcus aureus. In laboratory conditions, after 30 min of exposure to UV irradiation (λ = 254 nm), the DNA/CQDs complex significantly increased its fluorescence. Further, stratospheric probe was suggested and crafted by using technology of 3D printing (acrylonitrile–butadiene–styrene as a material). CQDs were exploited to evaluate the DNA damage in stratospheric conditions (up to 20,000 m) by determination of fluorescence increase (λ exc = 245 nm, λ em = 400 nm), together with other parameters (temperature, humidity, altitude, pressure, UV intensity, and X-ray irradiation). The obtained data showed that the sensor utilizing the DNA/CQDs was able to identify the DNA damage, together with external conditions. It was shown the proposed concept is able to operate at temperatures lower than −70 °C. The proposed protocol may by applicable as a biosensor for long-term space missions, like international space station, missions to the Moon or Mars.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28773383,

title = {Nanoparticles Suitable for BCAA Isolation Can Serve for Use in Magnetic Lipoplex-Based Delivery System for L, I, V, or R-rich Antimicrobial Peptides},

author = {Radek Vesely and Pavlina Jelinkova and Dagmar Hegerova and Natalia Cernei and Pavel Kopel and Amitava Moulick and Lukas Richtera and Zbynek Heger and Vojtech Adam and Ondrej Zitka},

doi = {10.3390/ma9040260},

issn = {1996-1944},

year  = {2016},

date = {2016-03-01},

journal = {Materials (Basel)},

volume = {9},

number = {4},

abstract = {This paper investigates the synthesis of paramagnetic nanoparticles, which are able to bind branched chain amino acids (BCAAs)-leucine, valine, and isoleucine and, thus, serve as a tool for their isolation. Further, by this, we present an approach for encapsulation of nanoparticles into a liposome cavity resulting in a delivery system. Analyses of valine and leucine in entire complex show that 31.3% and 32.6% recoveries are reached for those amino acids. Evaluation of results shows that the success rate of delivery in  () is higher in the case of BCAAs on nanoparticles entrapped in liposomes (28.7% and 34.7% for valine and leucine, respectively) when compared to nanoparticles with no liposomal envelope (18.3% and 13.7% for valine and leucine, respectively). The nanoparticles with no liposomal envelope exhibit the negative zeta potential (-9.1 ± 0.3 mV); however, their encapsulation results in a shift into positive values (range of 28.9 ± 0.4 to 33.1 ± 0.5 mV). Thus, electrostatic interactions with negatively-charged cell membranes (approx. -50 mV in the case of ) leads to a better uptake of cargo. Our delivery system was finally tested with the leucine-rich antimicrobial peptide (FALALKALKKALKKLKKALKKAL) and it is shown that hemocompatibility (7.5%) and antimicrobial activity of the entire complex against ,  (), and methicilin-resistant  (MRSA) is comparable or better than conventional penicillin antibiotics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electrochemical methods for study of influence of selenium nanoparticles on antioxidant status of rats},

author = {Horky, Pavel and Ruttkay-Nedecky, Branislav and Nejdl, Lukas and Richtera, Lukáš and Cernei, Natalia and Pohanka, Miroslav and Kopel, Pavel and Skladanka, Jiri and Hloucalová, Pavlína and Sláma, Petr and Nevrkla, Pavel and Mlejnková, Veronika and Klusonova, Iva and Kizek, Rene and Adam, Vojtech},

doi = {10.20964/110402799},

year  = {2016},

date = {2016-03-01},

urldate = {2016-03-01},

journal = {International journal of electrochemical science},

volume = {11},

abstract = {The aim of the experiment was to determine the effect of selenium nanoparticles (SeN) and selenium nanoparticles bound with glucose (SeN-GLU) on the antioxidant status of rats. The rats were fed with two defined forms of selenium nanoparticles for ten days. The first experimental group (n=6) was dosed with SeN solution (0.06 mg of Se per kg of body weight / day). The second experimental group (n=6) was dosed with SeN-GLU (0.06 mg of Se and 0.3 mg of glucose per kg of body weight / day). In both experimental groups, the antioxidant activity was decreased in rat plasma and increased in liver, when measured using the both free radicals (FR) and Fe rric Reducing Antioxidant Power (FRAP) method. Electrochemical technique (differential pulse voltammetry - DPV) was applied to analyze the content of metallothionein (MT) and heavy metals. The reduced and oxidized forms of glutathione were analyzed by high performance liquid chromatography with electrochemical detection (HPLC-ED). In the analysis of whole blood, a significant increase of reduced glutathione (GSH) by 41% (P < 0.05) was observed in the SeN-GLU group compared with the control goup. Higher levels of GSH were also observed in the SeN group by 12%, but without any statistical significance. On the other hand, a smaller increase in oxidized glutathione (GSSG) by 22% (P < 0.05) was observed for the SeN-GLU group and an insignificant decrease by 13% w as recorded for the SeN group which implies increased GSH/GSSG ratio and higher antioxidant activity for both SeN-GLU and SeN groups in the whole blood. In the assessing of GSH in erythrocytes, a linear increase was observed for each group. An increase by 14% in the SeN group and a significant increase by 19% (P < 0.05) in the SeN-GLU group of rats was recorded. The amount of GSSG was the highest in the SeN group (an increase by 21%). In the liver, decrease in both forms of glutathione was observed. MT values were significantly higher in erythrocytes, plasma and liver in the groups with addition of SeN and SeN-GLU, which again implies higher antioxidant activity. The levels of zinc and copper were not significantly changed in the plasma or in the liver. From these results, it is apparent that SeN and SeN-GLU may be considered as an alternative source of selenium for improving of antioxidant status of the animal organism, which is characterized by high usability.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Antiviral activity of fullerene C60 nanocrystals modified with derivatives of anionic antimicrobial peptide maximin H5},

author = {Simona Dostalova and Amitava Moulick and Vedran Milosavljevic and Roman Guran and Marketa Kominkova and Kristyna Cihalova and Zbynek Heger and Lucie Blazkova and Pavel Kopel and David Hynek and Marketa Vaculovicova and Vojtech Adam and Rene Kizek},

doi = {10.1007/s00706-016-1675-0},

year  = {2016},

date = {2016-03-01},

journal = {Monatshefte fuer Chemie/Chemical Monthly },

abstract = {Many active antiviral substances come from natural sources. In this way, peptides, isolated from Asian toad Bombina maxima, called maximins, are very promising. Most of them have good antimicrobial activity; however, derivatives of anionic 20 amino acids-long maximin H5 show also promising antiviral activity. The effect can be enhanced by binding to suitable nanocarriers such as fullerenes. In the present study, six mutants of maximin H5 were designed where aspartic acid at position 11 was replaced by asparagine, histidine, tyrosine, alanine, glycine, or valine. The binding yield of each peptide to fullerene C60 nanocrystals was studied by derivatization with fluorescent reagent fluorescamine. The antiviral activity of these peptides and peptides bound to fullerene C60 nanocrystals was studied using bacteriophage λ as a model virus. All of the designed peptides had higher antiviral activity compared to maximin H5. The highest antiviral activity was observed in case of maximin variants H5N, H5V, or H5Y. Moreover, the antiviral activity was dependent on the amount of peptide bound on the surface of fullerene C60 nanocrystals, which was enhanced by trimesic acid (benzene-1,3,5-tricarboxylic acid) treated fullerene C60 nanocrystals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid26462605,

title = {Bioconjugation of peptides using advanced nanomaterials to examine their interactions in 3D printed flow-through device},

author = {Petr Michalek and Lukas Richtera and Ludmila Krejcova and Lukas Nejdl and Renata Kensova and Jan Zitka and Pavel Kopel and Zbynek Heger and Vojtech Adam and Rene Kizek},

doi = {10.1002/elps.201500345},

issn = {1522-2683},

year  = {2016},

date = {2016-02-01},

journal = {Electrophoresis},

volume = {37},

number = {3},

pages = {444--454},

abstract = {Peptide-peptide interactions are crucial in the living cell as they lead to the formation of the numerous types of complexes. In this study, synthetic peptides containing 11 of cysteines (α-domain of metallothionein (MT)) and sialic acid binding region (130-loop of hemagglutinin (HA)) were employed. The aim of the experiment was studying the interactions between MT and HA-derived peptides. For this purpose, fragments were tagged with cysteines at C-terminal part to serve as ligand sites for PbS and CuS quantum dots (QDs), and therefore these conjugates can be traced and quantified during wide spectrum of methods. As a platform for interaction, γ-Fe2O3 paramagnetic particles modified with tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane (hydrodynamic diameter 30-40 nm) were utilized and MT/HA interactions were examined using multi-instrumental approach including electrochemistry, electrophoretic methods, and MALDI-TOF/TOF mass spectrometry. It was found that peptides enter mutual creation of complexes, which are based on some of nonbonded interactions. The higher willingness to interact was observed in MT-derived peptides toward immobilized HA. Finally, we designed and manufactured flow-through electrochemical 3D printed device (reservoir volume 150 μL) and utilized it for automated analysis of the HA/MT metal labels. Under the optimal conditions, (deposition time and flow rate 80 s and 1.6 mL/min for CuS and 120 s and 1.6 mL/min PbS, respectively), the results of peptide-conjugated QDs were comparable with atomic absorption spectrometry.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28787832,

title = {Improved Electrochemical Detection of Zinc Ions Using Electrode Modified with Electrochemically Reduced Graphene Oxide},

author = {Jiri Kudr and Lukas Richtera and Lukas Nejdl and Kledi Xhaxhiu and Petr Vitek and Branislav Rutkay-Nedecky and David Hynek and Pavel Kopel and Vojtech Adam and Rene Kizek},

doi = {10.3390/ma9010031},

issn = {1996-1944},

year  = {2016},

date = {2016-01-01},

journal = {Materials (Basel)},

volume = {9},

number = {1},

abstract = {Increasing urbanization and industrialization lead to the release of metals into the biosphere, which has become a serious issue for public health. In this paper, the direct electrochemical reduction of zinc ions is studied using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The graphene oxide (GO) was fabricated using modified Hummers method and was electrochemically reduced on the surface of GCE by performing cyclic voltammograms from 0 to -1.5 V. The modification was optimized and properties of electrodes were determined using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The determination of Zn(II) was performed using differential pulse voltammetry technique, platinum wire as a counter electrode, and Ag/AgCl/3 M KCl reference electrode. Compared to the bare GCE the modified GCE/ERGO shows three times better electrocatalytic activity towards zinc ions, with an increase of reduction current along with a negative shift of reduction potential. Using GCE/ERGO detection limit 5 ng·mL was obtained.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@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}

}