“Theoretical investigation of grain size tuning during prolonged bias-enhanced nucleation”. Eckert M, Mortet V, Zhang L, Neyts E, Verbeeck J, Haenen ken, Bogaerts A, Chemistry of materials 23, 1414 (2011). http://doi.org/10.1021/cm102481y
Abstract: In this paper, the effects of prolonged bias-enhanced nucleation (prolonged BEN) on the growth mechanisms of diamond are investigated by molecular dynamics (MD) and combined MD-Metropolis Monte Carlo (MD-MMC) simulations. First, cumulative impacts of CxHy+ and Hx+ on an a-C:H/nanodiamond composite were simulated; second, nonconsecutive impacts of the dominant ions were simulated in order to understand the observed phenomena in more detail. As stated in the existing literature, the growth of diamond structures during prolonged BEN is a process that takes place below the surface of the growing film. The investigation of the penetration behavior of CxHy+ and Hx+ species shows that the carbon-containing ions remain trapped within this amorphous phase where they dominate mechanisms like precipitation of sp3 carbon clusters. The H+ ions, however, penetrate into the crystalline phase at high bias voltages (>100 V), destroying the perfect diamond structure. The experimentally measured reduction of grain sizes at high bias voltage, reported in the literature, might thus be related to penetrating H+ ions. Furthermore, the CxHy+ ions are found to be the most efficient sputtering agents, preventing the build up of defective material.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 9.466
Times cited: 9
DOI: 10.1021/cm102481y
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“Comparison of calculated and measured optical emission intensities in a direct current argon-copper glow discharge”. Bogaerts A, Donko Z, Kutasi K, Bano G, Pinhao N, Pinheiro M, Spectrochimica acta: part B : atomic spectroscopy 55, 1465 (2000). http://doi.org/10.1016/S0584-8547(00)00253-6
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 33
DOI: 10.1016/S0584-8547(00)00253-6
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“Computer simulations of argon-hydrogen Grimm-type glow discharges”. Bogaerts A, Journal of analytical atomic spectrometry 23, 1476 (2008). http://doi.org/10.1039/b810599e
Abstract: Computer simulations have been performed to describe the effect of small admixtures of hydrogen to an argon glow discharge in the Grimm-type configuration. The two-dimensional density profiles of the various plasma species (i.e., electrons, Ar+, ArH+, H+, H2+ and H3+ ions, H atoms and H2 molecules, Ar metastable atoms and sputtered Cu atoms) are presented for 1% H2 added to the argon glow discharge, and the effect of different H2 additions (varying between 0.1 and 10%) on the species densities, the hydrogen dissociation degree, and the sputtering process, are investigated. Finally, the relative contributions of various production and loss processes for the different plasma species are calculated.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.379
Times cited: 23
DOI: 10.1039/b810599e
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“The effect of the sampling cone position and diameter on the gas flow dynamics in an ICP”. Aghaei M, Lindner H, Bogaerts A, Journal of analytical atomic spectrometry 28, 1485 (2013). http://doi.org/10.1039/c3ja50107h
Abstract: An inductively coupled plasma, connected to a sampling cone of a mass spectrometer, is computationally investigated. The effects of the sampler orifice diameter (ranging from 1 to 2 mm) and distance of the sampler cone from the load coil (ranging from 7 to 17 mm) are studied. An increase in sampler orifice diameter leads to a higher central plasma temperature at the place of the sampler, as well as more efficient gas transfer through the sampler, by reducing the interaction of the plasma gas with the sampling cone. However, the flow velocity at the sampler position is found to be independent of the sampler orifice diameter. Moreover, by changing the sampler orifice diameter, we can control whether only the central gas or also the auxiliary gas can exit through the sampler. Finally, with the increasing distance of the sampler from the load coil, the plasma temperature at the place of the sampler decreases slightly, which might also have consequences for the ion generation and transport through the sampling cone.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.379
Times cited: 14
DOI: 10.1039/c3ja50107h
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“Modeling of glow discharge optical emission spectrometry: calculation of the argon atomic optical emission spectrum”. Bogaerts A, Gijbels R, Vlcek J, Spectrochimica acta: part B : atomic spectroscopy 53, 1517 (1998). http://doi.org/10.1016/S0584-8547(98)00139-6
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 44
DOI: 10.1016/S0584-8547(98)00139-6
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“Modeling of the target surface modification by reactive ion implantation during magnetron sputtering”. Depla D, Chen ZY, Bogaerts A, Ignatova V, de Gryse R, Gijbels R, Journal of vacuum science and technology: A: vacuum surfaces and films 22, 1524 (2004). http://doi.org/10.1116/1.1705641
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.374
Times cited: 13
DOI: 10.1116/1.1705641
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“Cytoglobin Silencing Promotes Melanoma Malignancy but Sensitizes for Ferroptosis and Pyroptosis Therapy Response”. De Backer J, Maric D, Zuhra K, Bogaerts A, Szabo C, Vanden Berghe W, Hoogewijs D, Antioxidants 11, 1548 (2022). http://doi.org/10.3390/antiox11081548
Abstract: Despite recent advances in melanoma treatment, there are still patients that either do not respond or develop resistance. This unresponsiveness and/or acquired resistance to therapy could be explained by the fact that some melanoma cells reside in a dedifferentiated state. Interestingly, this dedifferentiated state is associated with greater sensitivity to ferroptosis, a lipid peroxidation-reliant, iron-dependent form of cell death. Cytoglobin (CYGB) is an iron hexacoordinated globin that is highly enriched in melanocytes and frequently downregulated during melanomagenesis. In this study, we investigated the potential effect of CYGB on the cellular sensitivity towards (1S, 3R)-RAS-selective lethal small molecule (RSL3)-mediated ferroptosis in the G361 melanoma cells with abundant endogenous expression. Our findings show that an increased basal ROS level and higher degree of lipid peroxidation upon RSL3 treatment contribute to the increased sensitivity of CYGB knockdown G361 cells to ferroptosis. Furthermore, transcriptome analysis demonstrates the enrichment of multiple cancer malignancy pathways upon CYGB knockdown, supporting a tumor-suppressive role for CYGB. Remarkably, CYGB knockdown also triggers activation of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and subsequent induction of pyroptosis target genes. Altogether, we show that silencing of CYGB expression modulates cancer therapy sensitivity via regulation of ferroptosis and pyroptosis cell death signaling pathways.
Keywords: A1 Journal article; Pharmacology. Therapy; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Proteinscience, proteomics and epigenetic signaling (PPES)
Impact Factor: 7
DOI: 10.3390/antiox11081548
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“Computer simulations of a dielectric barrier discharge used for analytical spectrometry”. Martens T, Bogaerts A, Brok W, van Dijk J, Analytical and bioanalytical chemistry 388, 1583 (2007). http://doi.org/10.1007/s00216-007-1269-0
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.431
Times cited: 28
DOI: 10.1007/s00216-007-1269-0
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“Characterization of Non-Thermal Dielectric Barrier Discharges for Plasma Medicine: From Plastic Well Plates to Skin Surfaces”. Lin A, Gromov M, Nikiforov A, Smits E, Bogaerts A, Plasma Chemistry and Plasma Processing 43, 1587 (2023). http://doi.org/10.1007/s11090-023-10389-w
Abstract: technologies have been expanding, and one of the most exciting and rapidly growing
applications is in biology and medicine. Most biomedical studies with DBD plasma systems are performed in vitro, which include cells grown on the surface of plastic well plates, or in vivo, which include animal research models (e.g. mice, pigs). Since many DBD systems use the biological target as the secondary electrode for direct plasma generation and treatment, they are sensitive to the surface properties of the target, and thus can be altered based on the in vitro or in vivo system used. This could consequently affect biological response from plasma treatment. Therefore, in this study, we investigated the DBD plasma behavior both in vitro (i.e. 96-well flat bottom plates, 96-well U-bottom plates, and 24-well flat bottom plates), and in vivo (i.e. mouse skin). Intensified charge coupled device (ICCD) imaging was performed and the plasma discharges were visually distinguishable between the different systems. The geometry of the wells did not affect DBD plasma generation for low application distances (≤ 2 mm), but differentially affected plasma uniformity on the bottom of the well at greater distances. Since DBD plasma treatment in vitro is rarely performed in dry wells for plasma medicine experiments, the effect of well wetness was also investigated. In all in vitro cases, the uniformity of the DBD plasma was affected when comparing wet versus dry wells, with the plasma in the wide-bottom wells appearing the most similar to plasma generated on mouse skin. Interestingly, based on quantification of ICCD images, the DBD plasma intensity per surface area demonstrated an exponential one-phase decay with increasing application distance, regardless of the in vitro or in vivo system. This trend is similar to that of the energy per pulse of plasma, which is used to determine the total plasma treatment energy for biological systems. Optical emission spectroscopy performed on the plasma revealed similar trends in radical species generation between the plastic well plates and mouse skin. Therefore, taken together, DBD plasma intensity per surface area may be a valuable parameter to be used as a simple method for in situ monitoring during biological treatment and active plasma treatment control, which can be applied for in vitro and in vivo systems.
Keywords: A1 Journal Article; Non-thermal plasma · Plasma medicine · Dielectric barrier discharge · Plasma diagnostics · Plasma surface interaction · In situ plasma monitoring; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.6
DOI: 10.1007/s11090-023-10389-w
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“Modeling adatom surface processes during crystal growth: a new implementation of the Metropolis Monte Carlo algorithm”. Eckert M, Neyts E, Bogaerts A, CrystEngComm 11, 1597 (2009). http://doi.org/10.1039/b822973m
Abstract: In this paper, a new implementation of the Metropolis Monte Carlo (MMC) algorithm is presented. When combining the MMC model with a molecular dynamics (MD) code, crystal growth by plasma-enhanced chemical vapor deposition can be simulated. As the MD part simulates impacts of growth species onto the surface on a time scale of picoseconds, the MMC algorithm simulates the slower adatom surface processes. The implementation includes a criterion for the selection of atoms that are allowed to be displaced during the simulation, and a criterion of after how many MMC cycles the simulation is stopped. We performed combined MD-MMC simulations for hydrocarbon species that are important for the growth of ultrananocrystalline diamond (UNCD) films at partially hydrogenated diamond surfaces, since this implementation is part of a study of the growth mechanisms of (ultra)nanocrystalline diamond films. Exemplary for adatom arrangements during the growth of UNCD, the adatom surface behavior of C and C2H2 at diamond (111)1 × 1, C and C4H2 at diamond (111)1 × 1 and C3 at diamond (100)2 × 1 has been investigated. For all cases, the diamond crystal structure is pursued under the influence of MMC simulation. Additional longer time-scale MD simulations put forward very similar structures, verifying the MMC algorithm. Nevertheless, the MMC simulation time is typically one order of magnitude shorter than the MD simulation time.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.474
Times cited: 15
DOI: 10.1039/b822973m
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“Cold Atmospheric Plasma-Treated PBS Eliminates Immunosuppressive Pancreatic Stellate Cells and Induces Immunogenic Cell Death of Pancreatic Cancer Cells”. Van Loenhout J, Flieswasser T, Freire Boullosa L, De Waele J, Van Audenaerde J, Marcq E, Jacobs J, Lin A, Lion E, Dewitte H, Peeters M, Dewilde S, Lardon F, Bogaerts A, Deben C, Smits E, Cancers 11, 1597 (2019). http://doi.org/10.3390/cancers11101597
Abstract: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a low response to treatment and a five-year survival rate below 5%. The ineffectiveness of treatment is partly because of an immunosuppressive tumor microenvironment, which comprises tumor-supportive pancreatic stellate cells (PSCs). Therefore, new therapeutic strategies are needed to tackle both the immunosuppressive PSC and pancreatic cancer cells (PCCs). Recently, physical cold atmospheric plasma consisting of reactive oxygen and nitrogen species has emerged as a novel treatment option for cancer. In this study, we investigated the cytotoxicity of plasma-treated phosphate-buffered saline (pPBS) using three PSC lines and four PCC lines and examined the immunogenicity of the induced cell death. We observed a decrease in the viability of PSC and PCC after pPBS treatment, with a higher efficacy in the latter. Two PCC lines expressed and released damage-associated molecular patterns characteristic of the induction of immunogenic cell death (ICD). In addition, pPBS-treated PCC were highly phagocytosed by dendritic cells (DCs), resulting in the maturation of DC. This indicates the high potential of pPBS to trigger ICD. In contrast, pPBS induced no ICD in PSC. In general, pPBS treatment of PCCs and PSCs created a more immunostimulatory secretion profile (higher TNF-α and IFN-γ, lower TGF-β) in coculture with DC. Altogether, these data show that plasma treatment via pPBS has the potential to induce ICD in PCCs and to reduce the immunosuppressive tumor microenvironment created by PSCs. Therefore, these data provide a strong experimental basis for further in vivo validation, which might potentially open the way for more successful combination strategies with immunotherapy for PDAC.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Laboratory for Experimental Hematology (LEH); Center for Oncological Research (CORE)
Times cited: 6
DOI: 10.3390/cancers11101597
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“Covalent Cysteine Targeting of Bruton’s Tyrosine Kinase (BTK) Family by Withaferin-A Reduces Survival of Glucocorticoid-Resistant Multiple Myeloma MM1 Cells”. Logie E, Chirumamilla CS, Perez-Novo C, Shaw P, Declerck K, Palagani A, Rangarajan S, Cuypers B, De Neuter N, Mobashar Hussain Urf Turabe F, Kumar Verma N, Bogaerts A, Laukens K, Offner F, Van Vlierberghe P, Van Ostade X, Berghe WV, Cancers 13, 1618 (2021). http://doi.org/10.3390/cancers13071618
Abstract: Multiple myeloma (MM) is a hematological malignancy characterized by plasma cells’ uncontrolled growth. The major barrier in treating MM is the occurrence of primary and acquired therapy resistance to anticancer drugs. Often, this therapy resistance is associated with constitutive hyperactivation of tyrosine kinase signaling. Novel covalent kinase inhibitors, such as the clinically approved BTK inhibitor ibrutinib (IBR) and the preclinical phytochemical withaferin A (WA), have, therefore, gained pharmaceutical interest. Remarkably, WA is more effective than IBR in killing BTK-overexpressing glucocorticoid (GC)-resistant MM1R cells. To further characterize the kinase inhibitor profiles of WA and IBR in GC-resistant MM cells, we applied phosphopeptidome- and transcriptome-specific tyrosine kinome profiling. In contrast to IBR, WA was found to reverse BTK overexpression in GC-resistant MM1R cells. Furthermore, WA-induced cell death involves covalent cysteine targeting of Hinge-6 domain type tyrosine kinases of the kinase cysteinome classification, including inhibition of the hyperactivated BTK. Covalent interaction between WA and BTK could further be confirmed by biotin-based affinity purification and confocal microscopy. Similarly, molecular modeling suggests WA preferably targets conserved cysteines in the Hinge-6 region of the kinase cysteinome classification, favoring inhibition of multiple B-cell receptors (BCR) family kinases. Altogether, we show that WA’s promiscuous inhibition of multiple BTK family tyrosine kinases represents a highly effective strategy to overcome GC-therapy resistance in MM.
Keywords: A1 Journal article; ADReM Data Lab (ADReM); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.3390/cancers13071618
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“Monte Carlo method for simulations of adsorbed atom diffusion on a surface”. Liu YH, Neyts E, Bogaerts A, Diamond and related materials 15, 1629 (2006). http://doi.org/10.1016/j.diamond.2006.01.012
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.561
Times cited: 5
DOI: 10.1016/j.diamond.2006.01.012
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“How the alignment of adsorbed ortho H pairs determines the onset of selective carbon nanotube etching”. Khalilov U, Bogaerts A, Xu B, Kato T, Kaneko T, Neyts EC, Nanoscale 9, 1653 (2017). http://doi.org/10.1039/C6NR08005G
Abstract: Unlocking the enormous technological potential of carbon nanotubes strongly depends on our ability to specifically produce metallic or semiconducting tubes. While selective etching of both has already been demonstrated, the underlying reasons, however, remain elusive as yet. We here present computational and experimental evidence on the operative mechanisms at the atomic scale. We demonstrate that during the adsorption of H atoms and their coalescence, the adsorbed ortho hydrogen pairs on single-walled carbon nanotubes induce higher shear stresses than axial stresses, leading to the elongation of HC–CH bonds as a function of their alignment with the tube chirality vector, which we denote as the γ-angle. As a result, the C–C cleavage occurs more rapidly in nanotubes containing ortho H-pairs with a small γ-angle. This phenomenon can explain the selective etching of small-diameter semiconductor nanotubes with a similar curvature. Both theoretical and experimental results strongly indicate the important role of the γ-angle in the selective etching mechanisms of carbon nanotubes, in addition to the nanotube curvature and metallicity effects and lead us to clearly understand the onset of selective synthesis/removal of CNT-based materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 7.367
Times cited: 6
DOI: 10.1039/C6NR08005G
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“Reaction mechanisms of low-kinetic energy hydrocarbon radicals on typical hydrogenated amorphous carbon (a-C:H) sites: a molecular dynamics study”. Neyts E, Tacq M, Bogaerts A, Diamond and related materials 15, 1663 (2006). http://doi.org/10.1016/j.diamond.2006.02.003
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.561
Times cited: 18
DOI: 10.1016/j.diamond.2006.02.003
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“Grain size tuning of nanocrystalline chemical vapor deposited diamond by continuous electrical bias growth : experimental and theoretical study”. Mortet V, Zhang L, Eckert M, D'Haen J, Soltani A, Moreau M, Troadec D, Neyts E, De Jaeger JC, Verbeeck J, Bogaerts A, Van Tendeloo G, Haenen K, Wagner P, Physica status solidi : A : applications and materials science 209, 1675 (2012). http://doi.org/10.1002/pssa.201200581
Abstract: In this work, a detailed structural and spectroscopic study of nanocrystalline diamond (NCD) thin films grown by a continuous bias assisted CVD growth technique is reported. This technique allows the tuning of grain size and phase purity in the deposited material. The crystalline properties of the films are characterized by SEM, TEM, EELS, and Raman spectroscopy. A clear improvement of the crystalline structure of the nanograined diamond film is observed for low negative bias voltages, while high bias voltages lead to thin films consisting of diamond grains of only ∼10 nm nanometer in size, showing remarkable similarities with so-called ultrananocrystalline diamond. These layers arecharacterized by an increasing amount of sp2-bonded carbon content of the matrix in which the diamond grains are embedded. Classical molecular dynamics simulations support the observed experimental data, giving insight in the underlying mechanism for the observed increase in deposition rate with bias voltage. Furthermore, a high atomic concentration of hydrogen has been determined in these films. Finally, Raman scattering analyses confirm that the Raman line observed at ∼1150 cm−1 cannot be attributed to trans-poly-acetylene, which continues to be reported in literature, reassigning it to a deformation mode of CHx bonds in NCD.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.775
Times cited: 31
DOI: 10.1002/pssa.201200581
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“Collisional-radiative model for the sputtered copper atoms and ions in a direct current argon glow discharge”. Bogaerts A, Gijbels R, Carman RJ, Spectrochimica acta: part B : atomic spectroscopy 53, 1679 (1998). http://doi.org/10.1016/S0584-8547(98)00201-8
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 71
DOI: 10.1016/S0584-8547(98)00201-8
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“Postplasma Catalytic Model for NO Production: Revealing the Underlying Mechanisms to Improve the Process Efficiency”. Eshtehardi HA, van 't Veer K, Delplancke M-P, Reniers F, Bogaerts A, ACS Sustainable Chemistry and Engineering 11, 1720 (2023). http://doi.org/10.1021/acssuschemeng.2c05665
Abstract: Plasma catalysis is emerging for plasma-assisted gas conversion processes. However, the underlying mechanisms of plasma catalysis are poorly understood. In this work, we present a 1D heterogeneous catalysis model with axial dispersion (i.e., accounting for back-mixing and molecular diffusion of fluid elements in the process stream in the axial direction), for plasma-catalytic NO production from N2/O2 mixtures. We investigate the concentration and reaction rates of each species formed as a function of time and position across the catalyst, in order to determine the underlying mechanisms. To obtain insights into how the performance of the process can be further improved, we also study how changes in the postplasma gas flow composition entering the catalyst bed and in the operation conditions of the catalytic stage affect the performance of NO production.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.2c05665
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“Postplasma Catalytic Model for NO Production: Revealing the Underlying Mechanisms to Improve the Process Efficiency”. Eshtehardi HA, Van ‘t Veer K, Delplancke M-P, Reniers F, Bogaerts A, ACS Sustainable Chemistry and Engineering 11, 1720 (2023). http://doi.org/10.1021/acssuschemeng.2c05665
Abstract: Plasma catalysis is emerging for plasma-assisted gas conversion
processes. However, the underlying mechanisms of plasma catalysis are poorly
understood. In this work, we present a 1D heterogeneous catalysis model with axial
dispersion (i.e., accounting for back-mixing and molecular diffusion of fluid elements in
the process stream in the axial direction), for plasma-catalytic NO production from
N2/O2 mixtures. We investigate the concentration and reaction rates of each species
formed as a function of time and position across the catalyst, in order to determine the
underlying mechanisms. To obtain insights into how the performance of the process
can be further improved, we also study how changes in the postplasma gas flow
composition entering the catalyst bed and in the operation conditions of the catalytic
stage affect the performance of NO production.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.2c05665
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“Postplasma Catalytic Model for NO Production: Revealing the Underlying Mechanisms to Improve the Process Efficiency”. Eshtehardi HA, Van ‘t Veer K, Delplancke M-P, Reniers F, Bogaerts A, ACS Sustainable Chemistry and Engineering 11, 1720 (2023). http://doi.org/10.1021/acssuschemeng.2c05665
Abstract: Plasma catalysis is emerging for plasma-assisted gas conversion
processes. However, the underlying mechanisms of plasma catalysis are poorly
understood. In this work, we present a 1D heterogeneous catalysis model with axial
dispersion (i.e., accounting for back-mixing and molecular diffusion of fluid elements in
the process stream in the axial direction), for plasma-catalytic NO production from
N2/O2 mixtures. We investigate the concentration and reaction rates of each species
formed as a function of time and position across the catalyst, in order to determine the
underlying mechanisms. To obtain insights into how the performance of the process
can be further improved, we also study how changes in the postplasma gas flow
composition entering the catalyst bed and in the operation conditions of the catalytic
stage affect the performance of NO production.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 8.4
DOI: 10.1021/acssuschemeng.2c05665
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“Plasma treatment causes structural modifications in lysozyme, and increases cytotoxicity towards cancer cells”. Attri P, Kaushik NK, Kaushik N, Hammerschmid D, Privat-Maldonado A, De Backer J, Shiratani M, Choi EH, Bogaerts A, International Journal Of Biological Macromolecules 182, 1724 (2021). http://doi.org/10.1016/j.ijbiomac.2021.05.146
Abstract: Bacterial and mammalian proteins, such as lysozyme, are gaining increasing interest as anticancer drugs. This study aims to modify the lysozyme structure using cold atmospheric plasma to boost its cancer cell killing effect. We investigated the structure at acidic and neutral pH using various experimental techniques (circular dichroism, fluorescence, and mass spectrometry) and molecular dynamics simulations. The controlled structural modification of lysozyme at neutral pH enhances its activity, while the activity was lost at acidic pH at the same treatment conditions. Indeed, a larger number of amino acids were oxidized at acidic pH after plasma treatment, which results in a greater distortion of the lysozyme structure, whereas only limited structural changes were observed in lysozyme after plasma treatment at neutral pH. We found that the plasma-treated lysozyme significantly induced apoptosis to the cancer cells. Our results reveal that plasma-treated lysozyme could have potential as a new cancer cell killing drug.
Keywords: A1 Journal Article; Lysozyme; Cold atmospheric plasma; Cancer cell death; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.671
DOI: 10.1016/j.ijbiomac.2021.05.146
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“NOxproduction in a rotating gliding arc plasma: potential avenue for sustainable nitrogen fixation”. Jardali F, Van Alphen S, Creel J, Ahmadi Eshtehardi H, Axelsson M, Ingels R, Snyders R, Bogaerts A, Green Chemistry 23, 1748 (2021). http://doi.org/10.1039/D0GC03521A
Abstract: The fast growing world population demands food to survive, and nitrogen-based fertilizers are essential to ensure sufficient food production. Today, fertilizers are mainly produced from non-sustainable fossil fuels<italic>via</italic>the Haber–Bosch process, leading to serious environmental problems. We propose here a novel rotating gliding arc plasma, operating in air, for direct NO<sub>x</sub>production, which can yield high nitrogen content organic fertilizers without pollution associated with ammonia emission. We explored the efficiency of NO<sub>x</sub>production in a wide range of feed gas ratios, and for two arc modes: rotating and steady. When the arc is in steady mode, record-value NO<sub>x</sub>concentrations up to 5.5% are achieved which are 1.7 times higher than the maximum concentration obtained by the rotating arc mode, and with an energy consumption of 2.5 MJ mol<sup>−1</sup>(or<italic>ca.</italic>50 kW h kN<sup>−1</sup>);<italic>i.e.</italic>the lowest value so far achieved by atmospheric pressure plasma reactors. Computer modelling, using a combination of five different complementary approaches, provides a comprehensive picture of NO<sub>x</sub>formation in both arc modes; in particular, the higher NO<sub>x</sub>production in the steady arc mode is due to the combined thermal and vibrationally-promoted Zeldovich mechanisms.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 9.125
DOI: 10.1039/D0GC03521A
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“Power Pulsing To Maximize Vibrational Excitation Efficiency in N2Microwave Plasma: A Combined Experimental and Computational Study”. Van Alphen S, Vermeiren V, Butterworth T, van den Bekerom DCM, van Rooij GJ, Bogaerts A, Journal Of Physical Chemistry C 124, 1765 (2020). http://doi.org/10.1021/acs.jpcc.9b06053
Abstract: Plasma is gaining increasing interest for N2 fixation, being a flexible, electricity-driven alternative for the current conventional fossil fuel-based N2 fixation processes. As the vibrational-induced dissociation of N2 is found to be an energy-efficient pathway to acquire atomic N for the fixation processes, plasmas that are in vibrational nonequilibrium seem promising for this application. However, an important challenge in using nonequilibrium plasmas lies in preventing vibrational−translational (VT) relaxation processes, in which vibrational energy crucial for N2 dissociation is lost to gas heating. We present here both experimental and modeling results for the vibrational and gas temperature in a microsecond-pulsed microwave (MW) N2 plasma, showing how power pulsing can suppress this unfavorable VT relaxation and achieve a maximal vibrational nonequilibrium. By means of our kinetic model, we demonstrate that pulsed plasmas take advantage of the long time scale on which VT processes occur, yielding a very pronounced nonequilibrium over the whole N2 vibrational ladder. Additionally, the effect of pulse parameters like the pulse frequency and pulse width are investigated, demonstrating that the advantage of pulsing to inhibit VT relaxation diminishes for high pulse frequencies (around 7000 kHz) and long power pulses (above 400 μs). Nevertheless, all regimes studied here demonstrate a clear vibrational nonequilibrium while only requiring a limited power-on time, and thus, we may conclude that a pulsed plasma seems very interesting for energyefficient vibrational excitation.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.7
DOI: 10.1021/acs.jpcc.9b06053
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“Plasma-Catalytic Ammonia Reforming of Methane over Cu-Based Catalysts for the Production of HCN and H2at Reduced Temperature”. Yi Y, Wang X, Jafarzadeh A, Wang L, Liu P, He B, Yan J, Zhang R, Zhang H, Liu X, Guo H, Neyts EC, Bogaerts A, Acs Catalysis 11, 1765 (2021). http://doi.org/10.1021/acscatal.0c04940
Abstract: Industrial production of HCN from NH3 and CH4 not only uses precious Pt or Pt−Rh catalysts but also requires extremely high temperatures (∼1600 K). From an energetic, operational, and safety perspective, a drastic decrease in temperature is highly desirable. Here, we report ammonia reforming of methane for the production of HCN and H2 at 673 K by the combination of CH4/NH3 plasma and a supported Cu/silicalite-1 catalyst. 30% CH4 conversion has been achieved with 79% HCN selectivity. Catalyst characterization and plasma diagnostics reveal that the excellent reaction performance is attributed to metallic Cu active sites. In addition, we propose a possible reaction pathway, viz. E-R reactions with N, NH, NH2, and CH radicals produced in the plasma, for the production of HCN, based on density functional theory calculations. Importantly, the Cu/silicalite-1 catalyst costs less than 5% of the commercial Pt mesh catalyst.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 10.614
DOI: 10.1021/acscatal.0c04940
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“Cold Atmospheric Plasma Increases Temozolomide Sensitivity of Three-Dimensional Glioblastoma Spheroids via Oxidative Stress-Mediated DNA Damage”. Shaw P, Kumar N, Privat-Maldonado A, Smits E, Bogaerts A, Cancers 13, 1780 (2021). http://doi.org/10.3390/cancers13081780
Abstract: Glioblastoma multiforme (GBM) is the most frequent and aggressive primary malignant brain tumor in adults. Current standard radiotherapy and adjuvant chemotherapy with the alkylating agent temozolomide (TMZ) yield poor clinical outcome. This is due to the stem-like properties of tumor cells and genetic abnormalities in GBM, which contribute to resistance to TMZ and progression. In this study, we used cold atmospheric plasma (CAP) to enhance the sensitivity to TMZ through inhibition of antioxidant signaling (linked to TMZ resistance). We demonstrate that CAP indeed enhances the cytotoxicity of TMZ by targeting the antioxidant specific glutathione (GSH)/glutathione peroxidase 4 (GPX4) signaling. We optimized the threshold concentration of TMZ on five different GBM cell lines (U251, LN18, LN229, U87-MG and T98G). We combined TMZ with CAP and tested it on both TMZ-sensitive (U251, LN18 and LN229) and TMZ-resistant (U87-MG and T98G) cell lines using two-dimensional cell cultures. Subsequently, we used a three-dimensional spheroid model for the U251 (TMZ-sensitive) and U87-MG and T98G (TMZ-resistant) cells. The sensitivity of TMZ was enhanced, i.e., higher cytotoxicity and spheroid shrinkage was obtained when TMZ and CAP were administered together. We attribute the anticancer properties to the release of intracellular reactive oxygen species, through inhibiting the GSH/GPX4 antioxidant machinery, which can lead to DNA damage. Overall, our findings suggest that the combination of CAP with TMZ is a promising combination therapy to enhance the efficacy of TMZ towards the treatment of GBM spheroids.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Center for Oncological Research (CORE)
DOI: 10.3390/cancers13081780
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“Sustainable gas conversion by gliding arc plasmas: a new modelling approach for reactor design improvement”. Van Alphen S, Jardali F, Creel J, Trenchev G, Snyders R, Bogaerts A, Sustainable energy &, fuels 5, 1786 (2021). http://doi.org/10.1039/D0SE01782E
Abstract: Research in plasma reactor designs is developing rapidly as plasma technology is gaining increasing interest for sustainable gas conversion applications, like the conversion of greenhouse gases into value-added chemicals and renewable fuels, and fixation of N<sub>2</sub>from air into precursors of mineral fertilizer. As plasma is generated by electric power and can easily be switched on/off, these applications allows for efficient conversion and energy storage of intermittent renewable electricity. In this paper, we present a new comprehensive modelling approach for the design and development of gliding arc plasma reactors, which reveals the fluid dynamics, the arc behaviour and the plasma chemistry by solving a unique combination of five complementary models. This results in a complete description of the plasma process, which allows one to efficiently evaluate the performance of a reactor and indicate possible design improvements before actually building it. We demonstrate the capabilities of this method for an experimentally validated study of plasma-based NO<sub>x</sub>formation in a rotating gliding arc reactor, which is gaining increasing interest as a flexible, electricity-driven alternative for the Haber–Bosch process. The model demonstrates the importance of the vortex flow and the presence of a recirculation zone in the reactor, as well as the formation of hot spots in the plasma near the cathode pin and the anode wall that are responsible for most of the NO<sub>x</sub>formation. The model also reveals the underlying plasma chemistry and the vibrational non-equilibrium that exists due to the fast cooling during each arc rotation. Good agreement with experimental measurements on the studied reactor design proves the predictive capabilities of our modelling approach.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1039/D0SE01782E
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“One-dimensional modelling of a capacitively coupled rf plasma in silane/helium, including small concentrations of O2 and N2”. de Bleecker K, Herrebout D, Bogaerts A, Gijbels R, Descamps P, Journal of physics: D: applied physics 36, 1826 (2003)
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.588
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“Laser ablation for analytical sampling: what can we learn from modeling?”.Bogaerts A, Chen Z, Gijbels R, Vertes A, Spectrochimica acta: part B : atomic spectroscopy 58, 1867 (2003). http://doi.org/10.1016/j.sab.2003.08.004
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.241
Times cited: 321
DOI: 10.1016/j.sab.2003.08.004
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“Description of the thermalization process of the sputtered atoms in a glow discharge using a 3-dimensional Monte Carlo method”. Bogaerts A, van Straaten M, Gijbels R, Journal of applied physics 77, 1868 (1995). http://doi.org/10.1063/1.358887
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.183
Times cited: 87
DOI: 10.1063/1.358887
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“Molecular dynamics simulations for the growth of diamond-like carbon films from low kinetic energy species”. Neyts E, Bogaerts A, Gijbels R, Benedikt J, van den Sanden MCM, Diamond and related materials 13, 1873 (2004). http://doi.org/10.1016/j.diamond.2004.05.011
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.561
Times cited: 53
DOI: 10.1016/j.diamond.2004.05.011
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