7th International Conference on Nanomaterials - Research & Application
October 14th - 16th 2015 / Hotel Voronez I, Brno, Czech Republic, EU
Nowadays, the number of consumer products including nanomaterials in many fields is increasing. Products properties (durability, electrical and thermal conductivity etc.) are efficiently improved by combining nanomaterials. On the other hand, it is reported that nanoparticles cause lung inflammations. However, regulations of exposure for handling of those products are still under development. For this reason, it is necessary to develop measurement method for the exposure to nanoparticles released by using products containing nanomaterials.
This study aims at developing chamber to distinguish the background concentration from nanoparticle concentration released. Especially, the goal of system is possible to measure exposure for workers simply and stably. It is currently difficult for the worker to measure this exposure because of complexity of nanoparticles behavior. Hence, we created a chamber which it is possible to crush nanomaterials or spray them sealed conditions. This chamber is equipped with working gloves, ventilation systems and a circulation system with a pipeline. To test our method, we used a standard particles (sucrose, size is approximately 10 nm) generated by generator. The air circulation is regulated with a controlled ventilation speed so that the particles do not agglomerate through the pipe. Due to the chamber, we can obtain a representative concentration value in the pipe. As a result, The agglomeration rate was confirmed under 5 %.
Inorganic nanomaterials have large specific surface area and high bioactivity which made them promising alternatives to the traditional organic antimicrobial agents that are extremely irritant and toxic. In the present report, CdTe/ZnSe core/shell quantum dots (QDs) were conjugated with different nucleobases and their antibacterial activity against Escherichia coli was investigated. The CdTe/ZnSe core/shell QDs were synthesized in a green way or environment-friendly way using water as a solvent instead of organic solvents. They were successfully conjugated with different nucleobases and were characterized using fluorescence and absorbance spectrophotometry and dynamic light scattering techniques. The antimicrobial activity of all the samples along with control (bare QDs) was checked on E. coli, a commonly used bacterial model species in microbiology research. Almost all nucleobases showed good antibacterial activity comparing to control probably forming excess ROS which can disturb different metabolisms in bacterial cell. Guanine showed the best result among all other nucleobases.
The growth in the application of nanomaterials (of any structure in any use) leads to increasing concentrations in the environment. These nanomaterials may also enter into wastewater treatment plants and interact with activated sludge, so at least partial knowledge of the behaviour of nanoparticles in the activated sludge is essential. This paper deals with the feedback of sewage microorganisms
to nanostructures (nanoparticles or nanofibers). The main task was to observe the impact of nanostructures on the microorganisms based on microscopy access and image analysis procedures. The examination included changes in bacterial morphological properties (size and roughness), and the viability of the microorganisms. The experiments demonstrated an increase in the adhesion of the microorganisms to the nanofibers during the first few hours, a significant influence of the microorganism’s viability in the presence
of nanoparticles (reduced by up to 99 %); and a changeover of the bacterial morphological properties (dispersed into floc-forming clusters or vice versa) of the nanofibers and nanoparticles.
This paper deals with the observation and assessment of the impact of TiO2, SiO2 and ZrO2 nanoparticles on microorganisms in activated sludge. These nanoparticles were tested in three different concentrations – 100 mg/L, 300 mg/L and 500 mg/L. The influence of the nanoparticles was assessed especially through respirometric measurements and fluorescence microscopy using a Live/Dead Cells Kit, which allowed the observation of the activity (O2 consumption) and viability of the microorganisms in the tested activated sludge. In addition, the morphology of the activated sludge was observed using Gram staining under optical microscopy. The acute toxicity of nanoparticles was evaluated; however, no significant toxic effects for most of the tested nanoparticles were observed. The impact of the tested nanoparticles depends on their type and concentration. The most significant decrease in respiration measurements was observed in a sample containing nanoparticles of zirconium dioxide at a concentration of 500 mg/L, whereby the respiration was reduced by 45.3 % compared to the control sample. In contrast, respiration of samples containing nanoparticles of SiO2 (300 mg/L and 500 mg/L), TiO2 (500 mg/L) and ZrO2 (300 mg/L) was almost the same as the control sample.
Use of the biological and microbiological tests, in vitro assays and computational modeling for characterization of nanomaterials is presented and bioanalytical methods for sensitive and selective detection of nanomaterials effects towards selected biomolecules are evaluated. Among technical devices of this branch of bioanalytical chemistry, DNA-based biosensors have been numerously demonstrated as effective warning devices for tests of DNA affinity interactions and structural changes caused by chemicals and physical factors.
An effect of the CdTe and CdS quantum dots of various sizes and fluorescence intensity on a deep degradation of dsDNA under UV-C radiation was investigated. Electrochemical DNA-based biosensors composed of glassy carbon electrode with a dsDNA layer covered by the nanoparticles and cyclic voltammetry together with electrochemical impedance spectroscopy with the [Fe(CN)6]3-/4- redox indicator, as well as square-wave voltammetry of the guanine moiety signal were used for the evaluation of DNA degradation. To confirm the DNA degradation, gel electrophoresis after irradiation of the DNA solution containing CdTe or CdS has been performed as well. It was found that damage to DNA by UV-C is enhanced in the presence of quantum dots in dependence on their fluorescence ability.
ACKNOWLEDGEMENTS:
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-0797-11, the Scientific Grant Agency VEGA of the Slovak Republic (Project 1/0361/14) and the Competence Center for SMART Technologies for Electronics and Informatics Systems and Services, ITMS 26240220072, funded by the Research&Development Operational Programme from the ERDF.
Results of toxicity and ecotoxicity studies tend to be significantly affected by behavior of nanoparticles in physiological fluids or environmental media. The effort was focused on development of testing procedure applicable in common laboratory practice providing data, which are not distorted due to hardly controllable processes occurring during the experiment. The agarose gel was therefore employed as an exposure medium, which should supposedly suppress the rate of agglomeration and ensure homogeneous distribution of tested nanoparticles in the whole medium volume. Ecotoxicity of zinc oxide nanoparticle (ZnO-NPs) powder with the mean particle size diameter of 10 nm to the annelid Enchytraeus crypticus was tested in agarose gel. Two methods of ZnO-NPs powder introduction into exposure media were used. Within the first one, the nano-powder was initially cryogenically ground with the dry agar and then the water was added. The second procedure started with the re-suspension of nanoparticles in distilled water with the addition of dispersant (sodium pyrophosphate decahydrate). Obtained colloid was subsequently mixed with hot agar gel. Relative mortalities observed after 96h exposure of worms in cryogenically ground medium with 50, 100, 200, 500 and 1000 mg ZnO-NPs/kg agar ranged between 28.9 and 34.4 % and did not exhibit any concentration dependence. When the second exposure media preparation method was applied, the relative mortality ranged from 0 to 66.6 % at the same concentration region and showed concentration dependence. The results of particle size and amount of released zinc cation analysis showed, that observed ecotoxicity was obviously driven by size of ZnO-NPs agglomerates influenced by applied technique of exposure media preparation.
Many recent studies illustrate the removal of wide range of organic and inorganic contaminants from the real groundwater environment using nanoscale zero-valent iron (nZVI) particles. The decontamination processes are significantly connected with nZVI ability to migrate within groundwater at the polluted areas. What is also important is its fate after application to the groundwater and the transformation towards oxidized products. One of the pilot test is situated in an industrial factory Spolchemie, Ústí nad Labem (Czech Republic), which has a long-term chemical production history. Recently, the contaminated groundwater is treated by nZVI applied into array of wells. Groundwater and sediments were sampled from the bottom of 3 monitoring wells periodically during 7 months. The key characteristics of samples, for instance: total concentration of iron, particle size, morphology and form of iron/iron oxides were evaluated by combination of experimental techniques - AAS, SEM, TEM, XRD and Mössbauer spectroscopy. Generally, results from samples analyses proved good migration ability of nZVI and their concentration depends on the distance of application sites to the monitoring wells. Transformed products of applied nZVI such as ferric/ferrous oxides were determined in the selected samples. The gathered information about nZVI migration and fate is crucial for future remediation actions based on nZVI. Monitoring the behaviour of nZVI during remediation processes for sufficiently long time could lead to get information where and how can be nZVI spread during remediation processes or an exclusion of potentially dangerous effects on the environment.
ACKNOWLEDGEMENTS:
This work was supported by grants from the EU FP7 (project NANOREM) and TAČR ("Competence Centres", project No. TE01020218).
Our research is focused on the phase, structure and chemical analysis of the powder particles released by braking of cars from their brake components – disks and pads. The basic information on structure and phase composition was obtained by X-Ray Powder Diffraction, Mössbauer Spectroscopy, and scanning electron microscopy with EDX. The results of the particle analysis are compared with materials used for manufacturing brake components and with the powder prepared by ball milling of the mixture of the pad composite and disk steel. Most of recognized nanoparticles are based on carbon, silica/silicates and iron oxides. Their effects on street environment are mentioned.
Water pollution encourages the development of inovative treatments of wastewater which we can reuse. The aim of this study was to compare the filtration ability of selected nanomaterials for water clarifying and treatment. Commercially used nanofiltering materials and microfiltering material SPURTEX from SPUR a.s. Zlín were compared to each other.
Escherichia coli was selected for the representation of microbiological contamination. This bacterium is an important indicator of faecal contamination and its occurrence in water is strictly monitored. The spreading of this bacterium in a human being is the cause of a range of digestive and urogynaecological illnesses.
100 ml of contaminated water was filtrated at a pressure of 0,5 bar through a filtration device, which is made from anticorrosive steel and was sterilised before the experiment. For every sample, parameters of filtration were determined (filtration time, amount of bacteria before and after filtration, efficiency of filtration, etc.). In the samples, Escherichia coli on VRBL agar (Biokar Diagnostics, France) was determined using the plate cultivation method during 24 h at a temperature of 37 ˚C.
The conclusions of this study can show how to reuse wastewater by this filtration method which is relatively fast, effective and financially advantegous.
Submicron particles occuring in the environment are of natural origin, but are also formed by anthropogenic activities as secondary products. The source of these submicron particles are energy industries, ore processing, cosmetic and pharmaceutical industries, food, smoking, transportation. Chemical composition of these particles is not precisely known. Due to their size (˂1 µm) they can be easily inhaled and thus enter deep respiratory tract into the lungs. Depending on their size and chemical composition may have the ability to induce oxidative stress in cells, which may lead to damage to the body. An example might be the occurrence of unspecified peripheral T-cell lymphoma in a 74-year-old male patient, non-smoker, previously working in metal rollers worker. This case was evaluated from the pathological point of view, together with a detection of submicron particles / clusters in the sample of the tumor tissue. Histologically was the tumor in lung tissue inaccurately bounded with diffusely growing medium sized to large lymphoid elements having nuclei of irregular size and shape and with one or multiple nucleoli with prominent mitotic activity. In the tissue was also dispersed dark pigment and during examination by light microscopy at high magnification under polarized light was observed foreign particles probably of metallic character. Experimental method used included scanning electron microscopy (SEM-EDX) and Raman microspectroscopy. SEM-EDX revealed presence of particles/clusters in sizes ˂500 nm consisted mainly of iron. Occurrence of iron particles namely siderite (FeCO3) was confirmed by Raman microspectroscopy. Moreover the tumor tissue was identified to contain carbon black and graphite-based particles.
New nanomaterials are used in nearly every industrial area and provide many benefits. Nevertheless, with new properties of new nanomaterials come new potential risks. Social demands to ensure the safety of nanomaterials enters to forefront, taking into account risks, caused by nanomaterials production and use, and are connected with whole nanomaterial life cycle. Potential risks associated with the end-of-life of nanomaterials are an issue that needs to be addressed. Nanoparticles or transformed nanomaterials can be released during disposal methods and enter environment, what should be monitored.
Carbon based nanomaterials are interesting for incineration tests, because they might be eliminated totally. As the case study of nanoparticles release potential during incineration, multiwalled carbon nanotubes (MWCNTs) and carbon black were tested. The primary objective of tests described in this study consisted in validating, whether nanoparticles can be released in the gas phase during the combustion in static air and low-oxygen atmosphere. Nanoparticles (28 – 462 nm) were released from 875°C, resp. 925°C, to 1000°C for two types of MWCNTs. A comparison of nanoparticles size distribution and raw MWCNTs diameters indicates that fibres disintegrate during combustion. The highest nanoparticles concentrations were around diameter 30 – 70 nm. In nitrogen atmosphere thermogravimetric experiments showed mass decrease. There is a hypothesis that even very low-oxygen concentration leads to mass loss, probably due to oxidation of nanomaterials. SEM analysis of nanomaterials residue showed modified and variously deformed fibres with conical ends. So, there is hypothesis that needle-like fibre shapes of CNT are more toxic than other carbon nanomaterials.
The aim of the study was to develop a material suitable for wound dressing which would be also suitable for cell growth and cell proliferation. Such matrix should have the structure of interconnected pores and a high porosity to ensure the adequate penetration of the cells and the supply of nutrients to the cells during their formation, diffusion of waste products out of the matrix and exclusion the products of matrix degradation. The study is focused on optimization the method of preparation of 3D porous structures and subsequent testing of cytotoxicity of thus prepared structures. The cytotoxicity of the structers was tested on human fibroblast cells. Fibroblasts are the basic cells of fibrous tissue. The cytotoxicity was tested by measuring the cell viability and using XTT. Another performed test was the test of biocidity/biodegradability.
Our main objective was to determine the antimicrobial effects of selenium nanoparticles (SeNPs). For the testing of their influence we exploited isolates obtained from swabs from patients (n = 25) with hard-to-heal skin infections. Using mass spectrometry we identified 49 various bacterial strains. Antimicrobial properties of SeNPs were tested using measurement of inhibition zones; determination of growth curves and measurement of possible toxicity by inhibition of nucleic acid replication. Clinical isolates were exposed to the constant concentration of SeNPs (100 µg/mL). In almost all of bacterial strains we observed inhibition zones higher than 5 mm, which are the legislatively given as the lowest value for confirmation of effectivity of tested antimicrobial agents. The most sensitive strains were further exposed to the concentration range of selenium nanoparticles (0; 1; 2; 4; 8; 16; 32 and 48 µg/mL). Growth curves exhibited inhibition effects caused even by the lowest applied concentration (1 µg/mL) in all of tested bacterial isolates. In Escherichia fergusonii, Pseudomonas aeruginosa and Streptococcus agalactiae, application of 64 µg/mL of SeNPs resulted in total growth inhibition. We confirmed the antimicrobial effects of SeNPs, which may be used in the future for the elimination of hard-to-heal bacterial infections.