Gabriela Kratošová

Fungi as an efficient mycosystem for the synthesis of metal nanoparticles: progress and key aspects of research

Nanotechnology is an emerging cutting-edge technology, which involves interdisciplinary subjects, such as physics, chemistry, biology, material science and medicine. Different methods for the synthesis of nanoparticles have been discussed here. Although physical and chemical methods have been successfully used to synthesize nanoparticles, the use of hazardous chemicals and synthesis at high temperature is a matter of concern. Hence, there is a necessity to develop eco-friendly techniques for the synthesis of nanoparticles. Biosynthesis of nanoparticles by fungi, bacteria, actinomycetes, lichen and viruses have been reported eco-friendly. Moreover, the fungal system has emerged as an efficient system for nanoparticle synthesis as fungi possess distinctive characters including high wall binding capacity, easy to culture and simpler biomass handling, etc. In this review, we have discussed fungi as an important tool for the fabrication of nanoparticles. In addition, methods and mechanism for synthesis of nanoparticles and its potential applications have also been discussed.

Role of Al2O3 in Semi-Metallic Friction Materials and its Effects on Friction and Wear Performance

In this work the semi-metallic friction composites with moderately increased content of Al2O3 (0, 3.4, 5.6, 9.0, and 14.6 vol%) were successfully fabricated by casting technology and their tribological properties were evaluated. The character of friction surfaces was confirmed by SEM. The sample with 5.6 vol% of Al2O3 offers the best tribological property among the prepared formulations, and is characterized by high and steady friction coefficient (about 0.45) and low wear. With the temperature increasing, the stibnite patches population on friction surface increases and individual steel fibers spread due to their plastic deformation to form larger primary contact plateaus. The area covered by contact primary plateaus decreases with the alumina content increasing.

Biosynthesis of Metallic Nanoparticles and Their Applications

Biosynthesis and biofabrication of the metallic NPs have became an important approach to NP preparation. They are not only equal with the chemical or physical methods, but also offer quite a few assets compared to classical tacks. In this review, we present comprehensive overview of existing published records, which include clear and realistic application of biosynthesized metallic NPs. Our survey covers NP utilization from biosorption and catalysis to medicinal and sensing applications. Moreover, we add current review references and comparison (or synergy) with chemical and physical methods.

Physiological response of culture media-grown barley (Hordeum vulgare L.) to titanium oxide nanoparticles

ABSTRACT Since the fate of nanoparticles after their release in the environment and their possible transfer in plants and subsequent impacts is still largely unknown, this paper evaluates the potential phytotoxic effects of up to 20% w/w TiO2 nanoparticles (nTiO2) on barley cultivated in hydroponics and agar media. The X-ray diffraction analysis confirmed that nTiO2 powder corresponds to anatase phase. On agar medium only high concentrations of nTiO2 (10% and 20% w/w) induced significant inhibition of shoot growth. However, hydroponics treatment with nTiO2 up to 1000 mg L−1 did not show any adverse effect on the shoot growth. In both experiments, (i) root growth inhibition effects became visible with increasing concentration of nTiO2, (ii) plants treated with nTiO2 showed no change in chlorophyll a and b content, even though the plants absorbed nTiO2, (iii) weight of biomass treated with nTiO2 was not significantly different compared to control. Therefore, we assume that transport of nTiO2 into the aerial parts is limited due to the presence of effective mechanical or physiological barriers in roots. Overall, it appears that early root growth is a relevant indicator of potential effects of nTiO2 exposure. Our results also indicate that synthesized nTiO2 are not significantly toxic to the barley when applied at the concentrations used in this work, even though plants absorb titanium.

Adaptation of Acidithiobacillus bacteria to metallurgical wastes and its potential environmental risks

Metallurgical wastes – oxygen converter sludge, dust from cast iron production, lead matte, and slag from recycling of used lead batteries – were treated with Acidithiobacillus bacteria. Bacterial activity and adaptability on waste and some waste mixtures were investigated. Acidithiobacillus bacteria may easily attack oxygen converter sludge, lead matte and slag and affect the mobility of metals. Cast iron dust is not a suitable substrate for applied bacteria due to the absence of reduced sulfur and reduced iron in its mineralogical composition. Nevertheless, the pure culture was able to adapt to the mixture of this waste with slag. Disposal of these metallurgical wastes deserves special attention due to potential attack by microorganisms and consequent pH changes. According to subsequent release of hazardous substances to the environment, this phenomenon can lead to evident environmental risks.

Colloidal Bio-nanoparticles in Polymer Fibers: Current Trends and Future Prospects

Biotechnology and bio-nanotechnology are emerging fields that inspire vast scientific and engineering inquiry. Bio-nanotechnology is relatively new and dynamic, applying biological principles to produce new systems and materials at nanoscale level. Eco-friendly nanomaterial development and production by biosynthesis have an interesting niche, where metallic and functionally diverse biosynthesized nanoparticles (bio-NPs) are prepared by exploiting both biological processes in microorganisms and biochemical reactions in plant extracts and other biomass. The major advantage of this approach is one-step chemical reduction and stabilization, with the two principal components providing toxic-free intermediates in the bio-NP genesis. This heralds exciting possibilities for inexpensive NP production and consequent rapid and wide adoption of novel applications, such as incorporation of bio-NPs to augment polymer nanofiber properties.

Erratum to: Antimicrobial bionanocomposite–from precursors to the functional material in one simple step

In the published manuscript http://dx.doi.org/10.1007 /s11051-016-3664-y, the minimal inhibitory concentration (MIC) value for the monitored composites is incorrectly stated: 0.014 mg/ml is the stated value while the correct value is 0.14 mg/ml. The incorrect value does not influence the general concept of the article, its other results or its conclusions, nor it demands an in-depth revision of the published text. J Nanopart Res (2017) 19: 244 DOI 10.1007/s11051-017-3938-z

Investigation of Nanoparticles in Biological Objects by Electron Microscopy Techniques

Electron microscopy (EM) is the most used technique for materials characterisation. Both methods—scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with high resolution mode have become extensively used especially in nanomaterials research. This chapter provides a summary of modern EM techniques used for the analysis of nanoparticles. Regarding a broad spectrum of various nanomaterials being prepared to date or just naturally occurring in the environment, several case studies focusing on nanoparticles analysis by EM methods are introduced. Modified EM methods such as cryo techniques and environmental SEM (ESEM) are also mentioned because of their importance and great potential in research areas combining nanotechnology and biology.