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DDC: 540 × Subject: environment ×

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    Poisoning of bubble propelled catalytic micromotors: The chemical environment matters
    (Cambridge [u.a.] : Royal Society of Chemistry, 2013) Zhao, G.; Sanchez, S.; Schmidt, O.G.; Pumera, M.
    Self-propelled catalytic microjets have attracted considerable attention in recent years and these devices have exhibited the ability to move in complex media. The mechanism of propulsion is via the Pt catalysed decomposition of H2O2 and it is understood that the Pt surface is highly susceptible to poisoning by sulphur-containing molecules. Here, we show that important extracellular thiols as well as basic organic molecules can significantly hamper the motion of catalytic microjet engines. This is due to two different mechanisms: (i) molecules such as dimethyl sulfoxide can quench the hydroxyl radicals produced at Pt surfaces and reduce the amount of oxygen gas generated and (ii) molecules containing -SH, -SSR, and -SCH3 moieties can poison the catalytically active platinum surface, inhibiting the motion of the jet engines. It is essential that the presence of such molecules in the environment be taken into consideration for future design and operation of catalytic microjet engines. We show this effect on catalytic micromotors prepared by both rolled-up and electrodeposition approaches, demonstrating that such poisoning is universal for Pt catalyzed micromotors. We believe that our findings will contribute significantly to this field to develop alternative systems or catalysts for self-propulsion when practical applications in the real environment are considered.
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    Antioxidant Defense in Primary Murine Lung Cells following Short- and Long-Term Exposure to Plastic Particles
    (Basel : MDPI, 2023) Schmidt, Anke; Mühl, Melissa; Brito, Walison Augusto da Silva; Singer, Debora; Bekeschus, Sander
    Polystyrene nano- and micro-sized plastic particles (NMP) are one of the common plastic materials produced that dramatically pollute the environment, water, and oceanic habitats worldwide. NMP are continuously absorbed by the body through a number of routes, especially via intestinal ingestion, dermal uptake, and inhalation into the lung. Several studies provided evidence of NMP provoking oxidative stress and affecting cellular responses. Yet, the NMP effects on primary lung cells have not been studied. To this end, we isolated and cultured murine lung cells and exposed them short-term or long-term to polystyrene 0.2–6.0 µm-sized NMP. We studied cellular consequences regarding oxidative stress, morphology, and secretion profiling. Visualization, distribution, and expression analyses confirmed lung cells accumulating NMP and showed several significant correlations with particle size. Moreover, we found substantial evidence of biological consequences of small-scale NMP uptake in lung cells. Besides alterations of cytokine secretion profiles resulting in inflammatory responses, indicators of oxidative stress were identified that were accompanied by Nrf2 and β-catenin signaling changes. Our results serve as an important basis to point out the potential hazards of plastic contaminations and uptake in lung cells.
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    Advanced Materials Safety 2023: Abstract book
    (Zenodo, 2023) Leibniz Research Alliance Advanced Materials Safety
    With this abstract book, the organizers of the conference Advanced Materials Safety 2023, publish the abstracts of the works that are presented during the conference. The functionality of advanced materials, their impact on humans and the environment as well as the acceptance of the technologies are the focus of the conference. With the Advanced Materials Safety 2023, we bring together researchers with different relevant expertise and identify possible interfaces for joint research projects that allow us to investigate such complex challenges.