Impact of gold-1-decanethiol-SAM formation and removal cycles on the surface properties of polycrystalline gold and SAM quality

Thal, Dana; Kahlert, Heike; Jeyabharathi, C.; Ahrens, Paula; Hasse, Ulrich

doi:10.1007/s10008-017-3858-y

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…The gold surface was cleaned based on a protocol by (Thal et al) 99 . Briefly, a polycrystalline gold electrodes (Ø 2 mm; Metrohm, Germany) were mechanically polished with Al 2 O 3 powder (Buehler; grain sizes 300 and 50 nm), and then the rest of alumina particles were removed by sonication from the surface of electrode.…”

Section: Methodsmentioning

confidence: 99%

A combination of electrochemistry and mass spectrometry to monitor the interaction of reactive species with supported lipid bilayers

Ravandeh

Kahlert

Jablonowski

et al. 2020

Sci Rep

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Reactive oxygen and nitrogen species (RONS), e.g. generated by cold physical plasma (CPP) or photodynamic therapy, interfere with redox signaling pathways of mammalian cells, inducing downstream consequences spanning from migratory impairment to apoptotic cell death. However, the more austere impact of RONS on cancer cells remains yet to be clarified. In the present study, a combination of electrochemistry and high-resolution mass spectrometry was developed to investigate the resilience of solid-supported lipid bilayers towards plasma-derived reactive species in dependence of their composition. A 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayer was undisturbed by 200 µM H2O2 (control) but showed full permeability after CPP treatment and space-occupying oxidation products such as PoxnoPC, PAzePC, and POPC hydroperoxide were found. Electron paramagnetic resonance spectroscopy demonstrated the presence of hydroxyl radicals and superoxide anion/hydroperoxyl radicals during the treatment. In contrast, small amounts of the intramembrane antioxidant coenzyme Q10 protected the bilayer to 50% and LysoPC was the only POPC derivative found, confirming the membrane protective effect of Q10. Such, the lipid membrane composition including the presence of antioxidants determines the impact of pro-oxidant signals. Given the differences in membrane composition of cancer and healthy cells, this supports the application of cold physical plasma for cancer treatment. In addition, the developed model using the combination of electrochemistry and mass spectrometry could be a promising method to study the effect of reactive species or mixes thereof generated by chemical or physical sources.

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Section: Methodsmentioning

confidence: 99%

A combination of electrochemistry and mass spectrometry to monitor the interaction of reactive species with supported lipid bilayers

Ravandeh

Kahlert

Jablonowski

et al. 2020

Sci Rep

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“…The surface of a polycrystalline gold electrode (Ø 2 mm; Metrohm, Filderstadt, Germany) was cleaned by mechanical polishing with Al 2 O 3 powder (Buehler, Esslingen, Germany); grain sizes 300 and 50 nm), and electrochemical cleaning by cyclic voltammetry (CV) from 0 to 1.5 V in 0.1 M H 2 SO 4 at 0.1 V s −1 for about 40 cycles. Moreover, by additional 10 cycles in 0.1 M H 2 SO 4 from 0.75 to 0.2 V at 0.1 V·s −1 the gold oxides were removed from the surface of the electrode [ 66 , 76 ].…”

Section: Methodsmentioning

confidence: 99%

Protective Role of Sphingomyelin in Eye Lens Cell Membrane Model against Oxidative Stress

et al. 2021

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In the eye lens cell membrane, the lipid composition changes during the aging process: the proportion of sphingomyelins (SM) increases, that of phosphatidylcholines decreases. To investigate the protective role of the SMs in the lens cell membrane against oxidative damage, analytical techniques such as electrochemistry, high-resolution mass spectrometry (HR-MS), and atomic force microscopy (AFM) were applied. Supported lipid bilayers (SLB) were prepared to mimic the lens cell membrane with different fractions of PLPC/SM (PLPC: 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine). The SLBs were treated with cold physical plasma. A protective effect of 30% and 44% in the presence of 25%, and 75% SM in the bilayer was observed, respectively. PLPC and SM oxidation products were determined via HR-MS for SLBs after plasma treatment. The yield of fragments gradually decreased as the SM ratio increased. Topographic images obtained by AFM of PLPC-bilayers showed SLB degradation and pore formation after plasma treatment, no degradation was observed in PLPC/SM bilayers. The results of all techniques confirm the protective role of SM in the membrane against oxidative damage and support the idea that the SM content in lens cell membrane is increased during aging in the absence of effective antioxidant systems to protect the eye from oxidative damage and to prolong lens transparency.

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“…The evolution of the Pb‐UPD signal is similar to the removal of a self‐assembled thiol monolayer from the Au surface by hydroxyl radicals. [ 28 ] The UV–vis absorption spectra of EC‐Au 25 NCs after Pb‐UPD cycling show unaltered absorption spectra after cycling in the UPD potential window. This indicates the refinement of exposed Au sites retaining the core structure (Figure 3d).…”

Section: Resultsmentioning

confidence: 99%

Platinum‐Grafted Twenty‐Five Atom Gold Nanoclusters for Robust Hydrogen Evolution

Mymoona,

Rival,

Nonappa

et al. 2023

Small

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A robust hydrogen evolution is demonstrated from Au25(PET)18]− nanoclusters (PET = 2‐phenylethanethiol) grafted with minimal platinum atoms. The fabrication involves an electrochemical activation of nanoclusters by partial removal of thiols, without affecting the metallic core, which exposes Au‐sites adsorbed with hydrogen and enables an electroless grafting of platinum. The exposed Au‐sites feature the (111)‐facet of the fcc‐Au25 nanoclusters as assessed through lead underpotential deposition. The electrochemically activated nanoclusters (without Pt loading) show better electrocatalytic reactivity toward hydrogen evolution reaction than the pristine nanoclusters in an acidic medium. The platinum‐grafted nanocluster outperformed with a lower overpotential of 0.117 V vs RHE (RHE = Reversible Hydrogen Electrode) compared to electrochemically activated nanoclusters (0.353 V vs RHE ) at 10 mA cm−2 and is comparable with commercial Pt/C. The electrochemically activated nanoclusters show better reactivity at higher current density owing to the ease of hydrogen release from the active sites. The modified nanoclusters show unique supramolecular self‐assembly characteristics as observed in electron microscopy and tomography due to the possible metallophilic interactions. These results suggest that the post‐surface modification of nanoclusters will be an ideal tool to address the sustainable production of green hydrogen.

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Impact of gold-1-decanethiol-SAM formation and removal cycles on the surface properties of polycrystalline gold and SAM quality

Cited by 7 publications

References 23 publications

A combination of electrochemistry and mass spectrometry to monitor the interaction of reactive species with supported lipid bilayers

A combination of electrochemistry and mass spectrometry to monitor the interaction of reactive species with supported lipid bilayers

Protective Role of Sphingomyelin in Eye Lens Cell Membrane Model against Oxidative Stress

Platinum‐Grafted Twenty‐Five Atom Gold Nanoclusters for Robust Hydrogen Evolution

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