This study investigates an environmentally benign approach to generate platinum nanoparticles (Pt NP) supported on the reduced graphene oxide (RGO) by non-edible gum waste of gum kondagogu (GK). The reaction adheres to the green chemistry approach by using an aqueous medium and a nontoxic natural reductant-GK-whose abundant hydroxyl groups facilitate in the reduction process of platinum salt and helps as well in the homogenous distribution of ensued Pt NP on RGO sheets. Scanning Electron Microscopy (SEM) confirmed the formation of kondagogu gum/reduced graphene oxide framed spherical platinum nanoparticles (RGO-Pt) with an average particle size of 3.3 ± 0.6 nm, as affirmed by Transmission Electron Microscopy (TEM). X-ray Diffraction (XRD) results indicated that the Pt NPs formed are crystalline with a face-centered cubic structure, while morphological analysis by XRD and Raman spectroscopy revealed a simultaneous reduction of GO and Pt. The hydrogenation of 4-nitrophenol could be accomplished in the superior catalytic performance of RGO-Pt. The current strategy emphasizes a simple, fast and environmentally benign technique to generate low-cost gum waste supported nanoparticles with a commendable catalytic activity that can be exploited in environmental applications.

• Klíčová slova
• 4-nitrophenol reduction, Pt nanoparticle, RGO, greener catalysts, kondagogu gum,
• MeSH
• Bixaceae chemie   MeSH
• difrakce rentgenového záření MeSH
• grafit chemie   MeSH
• katalýza MeSH
• kovové nanočástice chemie   ultrastruktura   MeSH
• nitrofenoly MeSH
• oxidace-redukce MeSH
• platina chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 4-nitrophenol MeSH Prohlížeč
• grafit MeSH
• graphene oxide MeSH Prohlížeč
• nitrofenoly MeSH
• platina MeSH

OBJECTIVES: The aim of this study was to clarify the influence of three different sizes of platinum nanoparticles on aquatic ecosystem and assess the toxic effect in term of particle size. Tests were conducted on organisms representing all trophic levels of the aquatic ecosystem, namely producers (duckweed Lemna minor), consumers (water fleas Daphnia magna) and decomposers (bacteria Vibrio fischeri). DESIGN: Experiments were carried out methodologically in accordance with the following standards: OECD 221 guideline (Lemna sp. Growth Inhibition test), OECD 202 guideline (Inhibition of the mobility of Daphnia magna) and ISO 11348-2 (Inhibitory effect of platinum nanoparticles on the light emission of Vibrio fischeri). RESULTS: The most toxic have been the smallest sized platinum nanoparticles for all tested organisms. The highest toxicity of all tested samples (Pt1, Pt2, Pt3) was observed in bacteria (30´EC50 = 135.47; 167.94; 254.64 µg.L-1), respectively. The lowest toxicity was recorded for Daphnia (48hEC50 = 405.74; 413.24; 514.07 µg.L-1), respectively. CONCLUSION: The ecotoxicity of platinum nanoparticles varies considerably according to the test organisms and particle size.

• MeSH
• Aliivibrio fischeri MeSH
• Daphnia MeSH
• kovové nanočástice chemie   toxicita   MeSH
• látky znečišťující vodu toxicita   MeSH
• platina chemie   toxicita   MeSH
• společenstvo MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• látky znečišťující vodu MeSH
• platina MeSH

Sparsely tested group of platinum nanoparticles (PtNPs) may have a comparable effect as complex platinum compounds. The aim of this study was to observe the effect of PtNPs in in vitro amplification of DNA fragment of phage λ, on the bacterial cultures (Staphylococcus aureus), human foreskin fibroblasts and erythrocytes. In vitro synthesized PtNPs were characterized by dynamic light scattering (PtNPs size range 4.8-11.7 nm), zeta potential measurements (-15 mV at pH 7.4), X-ray fluorescence, UV/vis spectrophotometry and atomic absorption spectrometry. The PtNPs inhibited the DNA replication and affected the secondary structure of DNA at higher concentrations, which was confirmed by polymerase chain reaction, DNA sequencing and DNA denaturation experiments. Further, cisplatin (CisPt), as traditional chemotherapy agent, was used in all parallel experiments. Moreover, the encapsulation of PtNPs in liposomes (LipoPtNPs) caused an approximately 2.4x higher of DNA damage in comparison with CisPt, LipoCisPt and PtNPs. The encapsulation of PtNPs in liposomes also increased their antibacterial, cytostatic and cytotoxic effect, which was determined by the method of growth curves on S. aureus and HFF cells. In addition, both the bare and encapsulated PtNPs caused lower oxidative stress (determined by GSH/GSSG ratio) in the human erythrocytes compared to the bare and encapsulated CisPt. CisPt was used in all parallel experiments as traditional chemotherapy agent.

• MeSH
• buněčné linie MeSH
• erytrocyty účinky léků   MeSH
• fibroblasty účinky léků   MeSH
• kovové nanočástice škodlivé účinky   chemie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• oxidační stres MeSH
• platina škodlivé účinky   chemie   MeSH
• poškození DNA * MeSH
• replikace DNA * MeSH
• Staphylococcus aureus účinky léků   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• platina MeSH

Although some metallic nanoparticles (NPs) are commonly used in the food processing plants as nanomaterials for food packaging, or as coatings on the food handling equipment, little is known about antimicrobial properties of palladium (PdNPs) and platinum (PtNPs) nanoparticles and their potential use in the food industry. In this study, common food-borne pathogens Salmonella enterica Infantis, Escherichia coli, Listeria monocytogenes and Staphylococcus aureus were tested. Both NPs reduced viable cells with the log10 CFU reduction of 0.3-2.4 (PdNPs) and 0.8-2.0 (PtNPs), average inhibitory rates of 55.2-99% for PdNPs and of 83.8-99% for PtNPs. However, both NPs seemed to be less effective for biofilm formation and its reduction. The most effective concentrations were evaluated to be 22.25-44.5 mg/L for PdNPs and 50.5-101 mg/L for PtNPs. Furthermore, the interactions of tested NPs with bacterial cell were visualized by transmission electron microscopy (TEM). TEM visualization confirmed that NPs entered bacteria and caused direct damage of the cell walls, which resulted in bacterial disruption. The in vitro cytotoxicity of individual NPs was determined in primary human renal tubular epithelial cells (HRTECs), human keratinocytes (HaCat), human dermal fibroblasts (HDFs), human epithelial kidney cells (HEK 293), and primary human coronary artery endothelial cells (HCAECs). Due to their antimicrobial properties on bacterial cells and no acute cytotoxicity, both types of NPs could potentially fight food-borne pathogens.

• Klíčová slova
• acute cytotoxicity, antimicrobial properties, food-borne pathogens, minimum inhibitory concentrations, palladium nanoparticles, platinum nanoparticles,
• MeSH
• antibakteriální látky chemie   farmakologie   MeSH
• Bacteria klasifikace   účinky léků   růst a vývoj   MeSH
• fibroblasty cytologie   účinky léků   MeSH
• kovové nanočástice aplikace a dávkování   chemie   MeSH
• kultivované buňky MeSH
• ledviny cytologie   účinky léků   MeSH
• lidé MeSH
• nemoci přenášené potravou prevence a kontrola   MeSH
• palladium chemie   MeSH
• platina chemie   MeSH
• potravinářská mikrobiologie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• palladium MeSH
• platina MeSH

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 24IC50 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.

• Klíčová slova
• Comet assay, Cytotoxicity, Haemocompatibility, Nanomedicine, Reactive oxygen species,
• MeSH
• buněčné linie MeSH
• buňky účinky léků   metabolismus   MeSH
• kovové nanočástice chemie   MeSH
• lidé MeSH
• nanotechnologie MeSH
• platina chemie   farmakologie   MeSH
• polymery chemická syntéza   chemie   MeSH
• povidon chemická syntéza   chemie   farmakologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• velikost částic MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• platina MeSH
• polymery MeSH
• povidon MeSH
• reaktivní formy kyslíku MeSH

The fabrication of nanoparticles using different formulations, and which can be used for the delivery of chemotherapeutics, has recently attracted considerable attention. We describe herein an innovative approach that may ultimately allow for the selective delivery of anticancer drugs to tumor cells by using an external magnet. A conventional antitumor drug, cisplatin, has been incorporated into new carboxymethylcellulose-stabilized magnetite nanoparticles conjugated with the fluorescent marker Alexa Fluor 488 or folic acid as targeting agent. The magnetic nanocarriers possess exceptionally high biocompatibility and colloidal stability. These cisplatin-loaded nanoparticles overcome the resistance mechanisms typical of free cisplatin. Moreover, experiments aimed at the localization of the nanoparticles driven by an external magnet in a medium that mimics physiological conditions confirmed that this localization can inhibit tumor cell growth site-specifically.

• Klíčová slova
• cytotoxicity, drug delivery, magnetic properties, nanoparticles, platinum,
• MeSH
• antitumorózní látky aplikace a dávkování   chemie   farmakokinetika   farmakologie   MeSH
• cisplatina aplikace a dávkování   chemie   farmakokinetika   farmakologie   MeSH
• kyselina listová chemie   MeSH
• lidé MeSH
• magnetické nanočástice chemie   MeSH
• nádorové buněčné linie MeSH
• platina chemie   MeSH
• sodná sůl karboxymethylcelulosy chemie   farmakokinetika   MeSH
• systémy cílené aplikace léků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antitumorózní látky MeSH
• cisplatina MeSH
• kyselina listová MeSH
• magnetické nanočástice MeSH
• platina MeSH
• sodná sůl karboxymethylcelulosy MeSH

Metallic nanoparticles (NPs) are promising nanomaterials used in different technological solutions as well as in consumer products. Silver (Ag), gold (Au) and platinum (Pt) represent three metallic NPs with current or suggested use in different applications. Pt is also used as vehicle exhaust catalyst leading to a possible exposure via inhalation. Despite their use, there is limited data on their genotoxic potential and possible size-dependent effects, particularly for Pt NPs. The aim of this study was to explore size-dependent genotoxicity of these NPs (5 and 50 nm) following exposure of human bronchial epithelial cells. We characterised the NPs and assessed the viability (Alamar blue assay), formation of DNA strand breaks (mini-gel comet assay) and induction of micronucleus (MN) analysed using flow cytometry (in vitro microflow kit). The results confirmed the primary size (5 and 50 nm) but showed agglomeration of all NPs in the serum free medium used. Slight reduced cell viability (tested up to 50 µg/ml) was observed following exposure to the Ag NPs of both particle sizes as well as to the smallest (5 nm) Au NPs. Similarly, at non-cytotoxic concentrations, both 5 and 50 nm-sized Ag NPs, as well as 5 nm-sized Au NPs, increased DNA strand breaks whereas for Pt NPs only the 50 nm size caused a slight increase in DNA damage. No clear induction of MN was observed in any of the doses tested (up to 20 µg/ml). Taken together, by using the comet assay our study shows DNA strand breaks induced by Ag NPs, without any obvious differences in size, whereas effects from Au and Pt NPs were size-dependent in the sense that the 5 nm-sized Au NPs and 50 nm-sized Pt NPs particles were active. No clear induction of MN was observed for the NPs.

• MeSH
• buněčné linie MeSH
• epitelové buňky účinky léků   MeSH
• kometový test metody   MeSH
• kovové nanočástice toxicita   ultrastruktura   MeSH
• mikrojaderné testy MeSH
• mikrojádra chromozomálně defektní účinky léků   MeSH
• platina * toxicita   MeSH
• poškození DNA účinky léků   MeSH
• průtoková cytometrie metody   MeSH
• stříbro * toxicita   MeSH
• testy genotoxicity metody   MeSH
• velikost částic MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zlato * toxicita   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• platina * MeSH
• stříbro * MeSH
• zlato * MeSH

Engineered and anthropogenic nanoparticles represent a new type of pollutants. Up until now, many studies have reported its adverse effect on biota, but the potential influence on the properties and functions of environmental compartments has largely been ignored. In this work, the effect of Pt nanoparticles on the functions and properties of model soil organic matter has been studied. Using differential scanning calorimetry and molecular modeling, the effect of a wide range of 3 nm Pt nanoparticles concentrations on water holding capacity, the strength of water binding, the stability of water molecule bridges and the content of aliphatic crystallites was studied. It was found that strong hydration of the nanoparticles influences the 3D water structural network and acts as kosmotropic agents (structure-forming) in water bridges and as chaotropic agents (i.e. water destructuring) in larger water volumes. Contrarily, the interaction with soil organic matter moieties partially eliminates these effects. As a result, the 3 nm Pt nanoparticles decreased the evaporation enthalpy of water in soil organic matter and supported soil desiccation. They also increased the strength of water molecule bridges and increased the soil structural rigidity even at low concentrations. Additionally, at high concentrations, they decreased the water content in soil organic matter and induced the aliphatic moieties' crystallization. It is concluded that the small-sized Pt nanoparticles, and perhaps other types as well, may affect the local physicochemical processes in soils and may consequently contribute to enhanced evapotranspiration and deterioration of soil functions.

• Klíčová slova
• Evaporation, Ice, Nanoparticles, Platinum, Soil, Water,
• Publikační typ
• časopisecké články MeSH

Electronic interactions between metal nanoparticles and oxide supports control the functionality of nanomaterials, for example, the stability, the activity and the selectivity of catalysts. Such interactions involve electron transfer across the metal/support interface. In this work we quantify this charge transfer on a well-defined platinum/ceria catalyst at particle sizes relevant for heterogeneous catalysis. Combining synchrotron-radiation photoelectron spectroscopy, scanning tunnelling microscopy and density functional calculations we show that the charge transfer per Pt atom is largest for Pt particles of around 50 atoms. Here, approximately one electron is transferred per ten Pt atoms from the nanoparticle to the support. For larger particles, the charge transfer reaches its intrinsic limit set by the support. For smaller particles, charge transfer is partially suppressed by nucleation at defects. These mechanistic and quantitative insights into charge transfer will help to make better use of particle size effects and electronic metal-support interactions in metal/oxide nanomaterials.

• MeSH
• cer chemie   MeSH
• elektrony * MeSH
• katalýza MeSH
• molekulární struktura MeSH
• nanočástice chemie   MeSH
• povrchové vlastnosti MeSH
• sloučeniny platiny chemie   MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cer MeSH
• ceric oxide MeSH Prohlížeč
• sloučeniny platiny MeSH

Structured catalytic membranes with high porosity and a low pressure drop are particularly suitable for industrial processes carried out at high space velocities. One of these processes is the catalytic total oxidation of volatile organic compounds, which is an economically feasible and environmentally friendly way of emission abatement. Noble metal catalysts are typically preferred due to high activity and stability. In this paper, the preparation of a thermally stable polybenzimidazole electrospun membrane, which can be used as a support for a platinum catalyst applicable in the total oxidation of volatile organic compounds, is reported for the first time. In contrast to commercial pelletized catalysts, high porosity of the membrane allowed for easy accessibility of the platinum active sites to the reactants and the catalytic bed exhibited a low pressure drop. We have shown that the preparation conditions can be tuned in order to obtain catalysts with a desired platinum particle size. In the gas-phase oxidation of ethanol, acetone, and toluene, the catalysts with Pt particle sizes 2.1 nm and 26 nm exhibited a lower catalytic activity than that with a Pt particle size of 12 nm. Catalysts with a Pt particle size of 2.1 nm and 12 nm were prepared by equilibrium adsorption, and the higher catalytic activity of the latter catalyst was ascribed to more reactive adsorbed oxygen species on larger Pt nanoparticles. On the other hand, the catalyst with a Pt particle size of 26 nm was prepared by a solvent evaporation method and contained less active polycrystalline platinum. Last but not least, the catalyst containing only 0.08 wt.% of platinum achieved high conversion (90%) of all the model volatile organic compounds at moderate temperatures (lower than 335 °C), which is important for reducing the costs of the abatement technology.

• Klíčová slova
• electrospinning, electrospun membranes, platinum catalysts, polybenzimidazole, volatile organic compounds,
• Publikační typ
• časopisecké články MeSH