1. Synthesis of complex concentrated nanoparticles by Ultrasonic Spray Pyrolysis and lyophilisationLidija Simić, Srečko Stopić, Bernd Friedrich, Matej Zadravec, Žiga Jelen, Rajko Bobovnik, Ivan Anžel, Rebeka Rudolf, 2022, original scientific article Abstract: The development of new multicomponent nanoparticles is gaining increasing importance
due to their specific functional properties, i.e., synthesised new complex concentrated nanoparticles
(CCNPs) in the form of powder using ultrasonic spray pyrolysis (USP) and lyophilisation from the
initial cast Ag20Pd20Pt20Cu20Ni20 alloy, which was in the function of the material after its catalytic
abilities had been exhausted. Hydrometallurgical treatment was used to dissolve the cast alloy,
from which the USP precursor was prepared. As a consequence of the incomplete dissolution of
the cast alloy and the formation of Pt and Ni complexes, it was found that the complete recycling
of the alloy is not possible. A microstructural examination of the synthesised CCNPs showed that
round and mostly spherical (not 100%) nanoparticles were formed, with an average diameter of
200 nm. Research has shown that CCNPs belong to the group with medium entropy characteristics.
A mechanism for the formation of CCNPs is proposed, based on the thermochemical analysis of
element reduction with the help of H2 and based on the mixing enthalpy of binary systems.
Keywords: complex concentrated nanoparticles, ultrasonic spray pyrolysis, lyophilisation, characterization, formation mechanism
Published in DKUM: 24.03.2025; Views: 0; Downloads: 7
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2. Synthesis of Ni/Y2O3 nanocomposite through USP and lyophilisation for possible use as coatingTilen Švarc, Srečko Stopić, Žiga Jelen, Matej Zadravec, Bernd Friedrich, Rebeka Rudolf, 2022, original scientific article Abstract: The Ni/Y2O3 catalyst showed high catalytic activity. Based on this, the aim of this study
was to create Ni/Y2O3 nanocomposites powder with two innovative technologies, Ultrasonic Spray
Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition of the generated
aerosols in an N2/H2 reduction atmosphere caused a complete decomposition of the nickel (II) nitrate
to elemental Ni, which became trapped on the formed Y2O3 nanoparticles. The Ni/Y2O3 nanocomposite particles were captured via gas washing in an aqueous solution of polyvinylpyrrolidone (PVP)
in collection bottles. PVP was chosen for its ability to stabilise nano-suspensions and as an effective
cryoprotectant. Consequently, there was no loss or agglomeration of Ni/Y2O3 nanocomposite material during the lyophilisation process. The Ni/Y2O3 nanocomposite powder was analysed using
ICP-MS, SEM-EDX, and XPS, which showed the impact of different precursor concentrations on the
final Ni/Y2O3 nanocomposite particle composition. In a final step, highly concentrated Ni/Y2O3
nanocomposite ink (Ni/Y2O3 > 0.140 g/mL) and test coatings from this ink were prepared by applying them on a white matte photo paper sheet. The reflection curve of the prepared Ni/Y2O3
nanocomposite coating showed a local maximum at 440 nm with a value of 39% reflection. Given that
Ni is located on the surface of the Ni/Y2O3 nanocomposite in the elemental state and according to the
identified properties, tests of the catalytic properties of this coating will be performed in the future.
Keywords: Ultrasonic Spray Pyrolysis (USP), lyophilisation, Ni/Y2O3 nanocomposite, characterisation, coatings
Published in DKUM: 20.03.2025; Views: 0; Downloads: 11
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4. Formation of bimetallic Fe/Au submicron particles with Ultrasonic Spray PyrolysisPeter Majerič, Darja Feizpour, Bernd Friedrich, Rebeka Rudolf, 2018, original scientific article Keywords: ultrasonic spray pyrolysis, precursor salts, formation mechanism, nanoparticle structure, Fe oxides, Au
Published in DKUM: 19.04.2018; Views: 1660; Downloads: 367
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5. Structure and formation model of Ag/TiO2 and Au/TiO2 nanoparticles synthesized through Ultrasonic Spray PyrolysisAlkan Gözde, Rebeka Rudolf, Jelena Bogovic, Darja Feizpour, Bernd Friedrich, 2017, original scientific article Keywords: ultrasonic spray pyrolysis, core shell nanostructure, formation mechanism, TiO2, Ag, Au
Published in DKUM: 26.09.2017; Views: 1469; Downloads: 449
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6. Size-dependent effects of gold nanoparticles uptake on maturation and antitumor functions of human dendritic cells in vitroSergej Tomić, Nina Ogrinc Potočnik, Rebeka Rudolf, Primož Pelicon, Ivan Anžel, Marjan Rupnik, Jelena Đokić, Saša Vasilijić, Dragana Vučević, Petar Milosavljević, Srđa Janković, Jelena Rajković, Bernd Friedrich, Miodrag Čolić, 2014, original scientific article Abstract: Gold nanoparticles (GNPs) are claimed as outstanding biomedical tools for cancer diagnostics and photo-thermal therapy, but without enough evidence on their potentially adverse immunological effects. Using a model of human dendritic cells (DCs), we showed that 10 nm- and 50 nm-sized GNPs (GNP10 and GNP50, respectively) were internalized predominantly via dynamin-dependent mechanisms, and they both impaired LPS-induced maturation and allostimulatory capacity of DCs, although the effect of GNP10 was more prominent. However, GNP10 inhibited LPS-induced production of IL-12p70 by DCs, and potentiated their Th2 polarization capacity, while GNP50 promoted Th17 polarization. Such effects of GNP10 correlated with a stronger inhibition of LPS-induced changes in Ca2+ oscillations, their higher number per DC, and more frequent extraendosomal localization, as judged by live-cell imaging, proton, and electron microscopy, respectively. Even when released from heat-killed necrotic HEp-2 cells, GNP10 inhibited the necrotic tumor cell-induced maturation and functions of DCs, potentiated their Th2/Th17 polarization capacity, and thus, impaired the DCs% capacity to induce T cell-mediated anti-tumor cytotoxicity in vitro. Therefore, GNP10 could potentially induce more adverse DC-mediated immunological effects, compared to GNP50.
Keywords: gold, nanoparticles, antitumor function
Published in DKUM: 19.06.2017; Views: 1517; Downloads: 413
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7. Morphology, aggregation properties, cytocompatibility and anti-inflammatory potential of citrate-stabilized AuNPs prepared by modular Ultrasonic Spray PyrolysisRebeka Rudolf, Peter Majerič, Sergej Tomić, Mohammed Shariq, Urban Ferčec, Bojan Budič, Bernd Friedrich, Dragana Vučević, Miodrag Čolić, 2017, original scientific article Abstract: Ultrasonic Spray Pyrolysis (USP) possesses a great potential for production of higher quantities of gold nanoparticles (AuNPs), thus overcoming the problem of batch-to-batch variations in their properties. Recently, we demonstrated that USP with an additional evaporation chamber (modular USP) led to a better size control of AuNPs. However, their morphology, stability, toxicity, and immunomodulatory properties have not been investigated completely. Here, two types of spherical AuNPs were produced by using different USP parameters, followed by their stabilization in Na-citrate solution. No significant changes in their size, agglomeration, and -potential occurred 3 months after their initial production in citrate solution. However, the conditioning of AuNPs in serum-containing cell culture media for 24 h induced an increase in the AuNPs’ hydrodynamic size and a red shift in their Surface Plasmon Resonance, pointing to their instability in biological media. Cytocompatibility tests showed that the produced AuNPs were internalized by L929 cells and primary human monocytes and were not cytotoxic at the concentrations lower than 200 μg/mL, but they exhibited antiproliferative and anti-inflammatory effects, respectively. AuNPs reduced the percentage of CD14+CD16+ but not CD14lowCD16+ monocytes in vitro and reduced the expression of CD86, HLA-DR, TNF-α, and IL-12/IL-23 by these cells. These results indicate that the anti-inflammatory effects of citrate-capped AuNPs produced by modular USP could be beneficial for their application in the treatment of inflammatory conditions.
Keywords: Ultrasonic Spray Pyrolysis, gold nanoparticles, plasmon resonance, monocytes, antiinflammatory effects
Published in DKUM: 14.06.2017; Views: 1594; Downloads: 476
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8. Synthesis of NiTi/Ni-TiO[sub]2 composite nanoparticles via ultrasonic spray pyrolysisPeter Majerič, Rebeka Rudolf, Ivan Anžel, Jelena Bogovic, Srečko Stopić, Bernd Friedrich, 2015, original scientific article Abstract: In this paper we present the production of NiTi/Ni-TiO2 composite nanoparticles via the synthesis method called ultrasonic spray pyrolysis (USP). The precursor solution for the synthesis of spherical NiTi particles was prepared from an orthodontic wire with a chemical composition of Ni (amount fraction x = 51.46 %) and Ti (x = 48.54 %). TEM microscopy, in combination with EDX analyses, was used for a detailed characterization of the obtained NiTi nanoparticles. The results showed the nanoparticle sizes ranging from 60 nm to 600 nm, depending on the parameters of the production procedure. This showed the versatility of the new USP synthesis procedure, proving its usefulness for different materials and applications.
Keywords: ultrasonic spray pyrolysis, NiTi/Ni-TiO2 composite nanoparticles, characterization, Transmission electron microscope (TEM), TEM microscopy
Published in DKUM: 23.03.2017; Views: 1610; Downloads: 141
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9. Au-nanoparticle synthesis via ultrasonic spray pyrolysis with a separate evaporation zonePeter Majerič, Bernd Friedrich, Rebeka Rudolf, 2015, original scientific article Abstract: Some experiments were conducted in connection with the gold-nanoparticle production in an effort to produce a more accurate model for determining the gold-nanoparticle synthesis with a modified ultrasonic spray pyrolysis (USP). As previous experi- ments with gold nanoparticles yielded nanoparticles of various shapes (spherical, triangular, cylindrical, etc.), a focus on synthesizing only spherical nanoparticles is underway, as a mixture of different shapes is difficult to characterize and utilize. One of the factors for the particle formation is droplet evaporation. In an attempt to produce the optimum conditions for droplet evaporation with the solvent diffusion and precipitation, a separate furnace and a separate reaction-gas inlet were used. This modification separates the evaporation stage from the reaction stage, compared to the standard USP set-up. Using relatively low temperatures, from 60 °C up to 140 °C, for the evaporation stage provides for more time and better conditions for the diffusion of the solvent into the center of a droplet and a higher probability of forming a spherical particle.
Keywords: nanotehnology, ultrasonic spray pyrolysis, gold, aerosol, TEM microscopy
Published in DKUM: 14.03.2017; Views: 1786; Downloads: 537
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10. Sinteza nanodelcev zlata z modificirano ultrazvočno razpršilno pirolizoPeter Majerič, 2016, doctoral dissertation Abstract: Doktorsko delo predstavlja študije, eksperimentalno delo, tehnike karakterizacije, rezultate in analize, s katerimi je povezana sinteza čistih, okroglih, neaglomeriranih nanodelcev zlata (AuNPs) z velikostjo okoli 50 nm. V prvem delu raziskav smo sintetizirali AuNPs s konvencionalno ultrazvočno razpršilno pirolizo (USP). Za surovino smo uporabili tetrakloroaurično kislino HAuCl4(s), ki smo jo raztopili v vodi. To raztopino smo v komori z ultrazvokom razpršili v kapljice, ki jih je nosilni plin N2 prenesel v reakcijsko peč. V tej peči so potekale stopnje sinteze: izhlapevanje kapljic, toplotna dekompozicija, redukcija s plinom H2 in zgoščevanje. Nastali so AuNPs različnih oblik z velikostmi do 300 nm, pri čemer smo identificirali visoko stopnjo aglomeracije. Ker s konvencionalnim USP nismo dosegli cilja, smo postavili hipotezo, da lahko izdelamo ciljne AuNPs z modificiranim USP, kjer je cona izhlapevanja kapljic ločena od reakcijske peči, reducirni plin pa je uveden neposredno v reakcijsko peč. Za potrditev hipoteze smo z eksperimenti preučevali vplivne parametre USP-sinteze: koncentracijo Au v začetni raztopini, temperature v coni izhlapevanja kapljic in v reakcijski peči ter pretok plinov N2 in H2. S pomočjo tehnik karakterizacij (TEM, DLS, ICP) na nastalih AuNPs smo ugotovili, da pri USP-sintezi hkrati potekata dva mehanizma nastanka nanodelcev (»kapljica-v-delec«, DTP in »plin-v-delec«, GTP). Z DTP nastajajo veliki nanodelci – do 300 nm, z GTP pa majhni – do 50 nm. Kadar potekata oba mehanizma hkrati, dobimo neugodno bimodalno velikostno porazdelitev AuNPs. Na tej osnovi smo postavili model nastanka AuNPs, ki pojasnjuje, kako lahko pri USP-sintezi s spreminjanjem koncentracije Au v začetni raztopini in pretokov plinov vplivamo na DTP in GTP mehanizma nastanka v korist GTP. S ciljno izbranimi parametri (0,5 g/l Au, 4,5 l/min N2, 2,0 l/min H2) smo ustvarili pogoje za nastanek AuNPs z GTP-mehanizmom. Pri tem so nastali okrogli AuNPs z ozko velikostno porazdelitvijo (37,0 ± 5,5 nm). Tako smo potrdili pravilnost postavljenega modela in hipotezo, da lahko z modificiranim USP izdelamo AuNPs ciljnih lastnosti.
Keywords: modificirana ultrazvočna razpršilna piroliza, nanodelci zlata, mehanizmi nastanka, karakterizacija
Published in DKUM: 08.06.2016; Views: 2267; Downloads: 235
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