Nanoparticle Release from Thermal Decomposition of Polymer Nanocomposites and the Biological Potential of the Emissions

Adding nanoparticles to polymers improves the properties significantly, such as UV resistance or even electrical conductivity. The growing use of these composite materials leads to a higher amount in disposals eventually. Within the circular economy there are two ways of handling: the recycling by shredding and reuse and the thermal treatment by combustion in municipal waste incinerators. In both cases there is nearly no information about the behavior of the nanoparticles and possible release scenarios. In this study a laboratory burner is used as a flexible set up to incinerate the polymer nanocomposites. The flue gas containing a complex mixture of combustion gases and particles is characterized by different particle analysers, PAH analysis, VOC analysis and TEM. The biological impact is studied by using a VITROCELL Automated ALI exposure station. Hereby, cells of the adenocarcino cell line A549 as well as a reconstituted bronchial epithelium (MucilAir, Epithelix) were exposed for 4 hours to the aerosols emitted from the combustion process. Within the exposure process, cells were exposed to the native aerosol, an aerosol under conditions to increase particle deposition via high voltage as well as a filtered aerosol, and therefore the sole gaseous phase. Furthermore, each exposure included a so-called clean air control, where cells where exposed to filtered air. The exposure was followed by a 21 h post-incubation before the cytotoxic effects were determined via LDH-release. To reveal if possible adverse effects are caused by the used nano-scaled filling material, all used nanomaterials did also undergo the same combustion process as a single material. Cytotoxicity studies showed no increased cytotoxic effects after the combustion of the sole nano-scaled filling materials. However, combustion of PE containing materials resulted in an enhanced LDH-release, and therefore cytotoxicity, in both cell culture models. Since no difference between exposures of unfiltered and filtered aerosols was apparent, it suggested that the observed cytotoxicity is due to the combustion induced gaseous phase

Proteomic analysis of the U1 snRNP of Schizosaccharomyces pombe reveals three essential organism-specific proteins

Characterization of spliceosomal complexes in the fission yeast Schizosaccharomyces pombe revealed particles sedimenting in the range of 30–60S, exclusively containing U1 snRNA. Here, we report the tandem affinity purification (TAP) of U1-specific protein complexes. The components of the complexes were identified using (LC-MS/MS) mass spectrometry. The fission yeast U1 snRNP contains 16 proteins, including the 7 Sm snRNP core proteins. In both fission and budding yeast, the U1 snRNP contains 9 and 10 U1 specific proteins, respectively, whereas the U1 particle found in mammalian cells contains only 3. Among the U1-specific proteins in S. pombe, three are homolog to the mammalian and six to the budding yeast Saccharomyces cerevisiae U1-specific proteins, whereas three, called U1H, U1J and U1L, are proteins specific to S. pombe. Furthermore, we demonstrate that the homolog of U1-70K and the three proteins specific to S. pombe are essential for growth. We will discuss the differences between the U1 snRNPs with respect to the organism-specific proteins found in the two yeasts and the resulting effect it has on pre-mRNA splicing