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Glucose-to-fructose isomerization is the key process in the reaction sequence that can lead to the total conversion of biomass into valuable fine chemicals. However, it is challenging to find an...

Purpose The biomedical applications of silver nanoparticles (AgNPs) are heavily investigated due to their cytotoxic and antimicrobial properties. However, the scientific literature is lacking in data on the aggregation behavior of nanoparticles, especially regarding its impact on biological activity. Therefore, to assess the potential of AgNPs in therapeutic applications, two different AgNP samples were compared under biorelevant conditions. Methods Citrate-capped nanosilver was produced by classical chemical reduction and stabilization with sodium citrate (AgNP@C), while green tea extract was used to produce silver nanoparticles in a green synthesis approach (AgNP@GTs). Particle size, morphology, and crystallinity were characterized using transmission electron microscopy. To observe the effects of the most important biorelevant conditions on AgNP colloidal stability, aggregation grade measurements were carried out using UV-Vis spectroscopy and dynamic light scatterig, while MTT assay and a microdilution method were performed to evaluate the effects of aggregation on cytotoxicity and antimicrobial activity in a time-dependent manner. Results The aggregation behavior of AgNPs is mostly affected by pH and electrolyte concentration, while the presence of biomolecules can improve particle stability due to the biomolecular corona effect. We demonstrated that high aggregation grade in both AgNP samples attenuated their toxic effect toward living cells. However, AgNP@GT proved less prone to aggregation thus retained a degree of its toxicity. Conclusion To our knowledge, this is the first systematic examination regarding AgNP aggregation behavior with simultaneous measurements of its effect on biological activity. We showed that nanoparticle behavior in complex systems can be estimated by simple compounds like sodium chloride and glutamine. Electrostatic stabilization might not be suitable for biomedical AgNP applications, while green synthesis approaches could offer new frontiers to preserve nanoparticle toxicity by enhancing colloidal stability. The importance of properly selected synthesis methods must be emphasized as they profoundly influence colloidal stability, and therefore biological activity.

Herein, the temperature-dependent electrical transport properties of single-walled carbon nanotube (SWCNT) thin films prepared by the electrohydrodynamic atomization technique, are reported. The physico–chemical properties of SWCNT thin films are characterized using X-ray diffraction, Raman, transmission electron, and field-emission scanning electron microscopy techniques. The electrical transport measurements are carried out from 285 to 20 K. A semiconducting behavior is observed when the temperature goes down to 20 K. The prevalent transport mechanism is analyzed with a variable-range hopping model, which is well aided by Raman analysis. Furthermore, the thermal dependence of the electrical conductivity of the SWCNT thin film is investigated using the Arrhenius model, which reveals the conductivity of the SWCNT thin film at low-temperature shows in the order of mega-Ohm resistance with a small activation energy of 1.81 J mol−1, and an exponential decrement in conductivity is observed while decreasing the temperature to 20 K, which further confirms the semiconducting behavior of the SWCNT thin film. The Poole–Frenkel conduction mechanism shows best fit for the temperatures 50, 75, and 100 K, and the results provide potential insights into the science and development of SWCNT research. Refereed/Peer-reviewed

Additional file 1.

The usage of semiconductor photocatalyst has been received great attention in recent years due to their wide application in photocatalytic water-splitting and degradation of pollutants in waste water and environmental remediation application, etc. In this study, we demonstrated the efficient synergistically piezo-phototronic effect (which is combined activity of piezo- and photocatalytic) of ZnO-Ag8S hybrid for the degradation of an organic dye. Hydrothermal method was adopted for the growth of ZnO tetrapods on the surface of glass substrate. Ag8S modified ZnO obtained by successive ionic layer adsorption and reaction (SILAR) method, has shown an increased photo-decolorization rate compared with bare photocatalyst. This piezo-photocatalytic hybrid material plays an important role in electron trapping and also hindered the charge carrier recombination. The photo-degradation mechanism of Rhodamine-B dye with Ag8S modified piezoelectric ZnO hybrid material has shown 7.3 fold increment when compared with bare photocatalyst. Our study reveals that ZnO-Ag8S hybrid shows a better visible-light piezophototronic activity which further explores a new catalyst design approach for existing photocatalytic application in environmental remediation.

Carbon paste electrodes (graphite/paraffin oil) bulk-modified with multiwalled carbon nanotubes (MWCNT) and chemically oxidized MWCNT (O-MWCNT) were used as sensors for the hydrodynamic chronoamperometric determination of hydrogen peroxide (H2O2). Experimental parameters, such as the type and pH of the supporting electrolyte or the working potential(s) applied were investigated in the batch arrangement.

Metal-containing nanoparticles have newly been recognized as one of the major factors in occupational and other inhalation exposures. Fumes containing manganese, cadmium or lead are formed in high-temperature industrial processes. Metal oxide (MnO2, CdO2, PbO) nano¬particles were synthesized and instilled in aqueous suspension in the trachea of rats for 6 weeks, and functional changes in the somatosensory system were studied. From treated rats, as well as untreated and vehicle controls, spontaneous and stimulus-evoked activity of the primary somatosensory cortex, and compound action potential from the tail nerve, were recorded in urethane anaesthesia. In the spontaneous activity there was a shift to higher frequencies in all treated groups. The latency of the somatosensory evoked potential was typically lengthened and its dependence on the frequency of stimulation increased by high dose of Cd and Pb, and by high and low dose of Mn. On the tail nerve, Pb had the strongest effect. The similarity of the three metals’ effects indicated common mechanisms of action, most likely disturbance of Ca-dependent neuronal phenomena and oxidative stress.