TY - JOUR A1 - Kieserling, Helena A1 - Sieg, Holger A1 - Heilscher, Jasmin A1 - Drusch, Stephan A1 - Braeuning, Albert A1 - Thünemann, Andreas A1 - Rohn, Sascha T1 - Towards Understanding Particle-Protein Complexes: Physicochemical, Structural, and Cellbiological Characterization of β-Lactoglobulin Interactions with Silica, Polylactic Acid, and Polyethylene Terephthalate Nanoparticles N2 - Nanoplastic particles and their additives are increasingly present in the food chain, interacting with biomacromolecules with not yet known consequences. A protein corona forms around the particles in these usually complex matrices, primarily with a first contact at surface-active proteins. However, systematic studies on the interactions between the particles and proteins –especially regarding protein affinity and structural changes due to surface properties like polarity – are limited. It is also unclear whether the protein corona can "mask" the particles, mimic protein properties, and induce cytotoxic effects when internalized by mammalian cells. This study aimed at investigating the physicochemical properties of model particle-protein complexes, the structural changes of adsorbed proteins, and their effects on Caco-2 cells. Whey protein β-lactoglobulin (β-Lg) was used as a well-characterized model protein and studied in a mixture with nanoparticles of varying polarity, specifically silica, polylactic acid (PLA), and polyethylene terephthalate (PET). The physicochemical analyses included measurements of the hydrodynamic diameter and the zeta potential, while the protein conformational changes were analyzed using Fourier-transform-infrared spectroscopy (FTIR) and intrinsic fluorescence. Cellular uptake in Caco-2 cells was assessed through flow cytometry, cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, and cellular impedance was analyzed with xCELLigence® technology. The results indicated that β-Lg had the highest affinity for hydrophilic silica particles, forming silica-β-Lg complexes and large aggregates through electrostatic interactions. The affinity decreased for PLA and was lowest for hydrophobic PET, which formed smaller complexes. Adsorption onto silica caused partial unfolding and refolding of β-Lg. The silica-β-Lg complexes were internalized by Caco-2 cells, impairing cell proliferation. In contrast, PLA- and PET-protein complexes were not internalized, though PLA complexes slightly reduced cell viability. This study enhances our understanding of protein adsorption on nanoparticles and its potential biological effects. KW - Nanoplastics KW - Microplastics KW - Reference materials KW - Scattering KW - DLS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630093 DO - https://doi.org/10.1016/j.colsurfb.2025.114702 SN - 1873-4367 VL - 253 SP - 1 EP - 12 PB - Elsevier BV CY - Amsterdam AN - OPUS4-63009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Maxi B. A1 - Böhmert, Linda A1 - Thünemann, Andreas A1 - Loeschner, Katrin A1 - Givelet, Lucas A1 - Fahrenson, Christoph A1 - Braeuning, Albert A1 - Sieg, Holger T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles. KW - Toxicology KW - Nanoparticles KW - Dynamic Light Scattering KW - Nanoplastics KW - Microplastics KW - Reference Method KW - Reference Material PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947 DO - https://doi.org/10.1016/j.fct.2023.114423 SN - 0278-6915 VL - 184 SP - 1 EP - 16 PB - Elsevier B.V. AN - OPUS4-59394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sieg, Holger A1 - Heilscher, Jasmin A1 - Ott, Franziska A1 - Böhmert, Linda A1 - Drusch, Stephan A1 - Thünemann, Andreas A1 - Rohn, Sascha A1 - Braeuning, Albert A1 - Kieserling, Helena T1 - Direct Interactions of Micro- and Nanoplastics with Proteins – A Key to Mechanistic Understanding? N2 - Micro-/Nanoplastics (MNP) have gained widespread scientific and public attention within the last two decades. While knowledge about measuring techniques, occurrence and exposure was improved substantially, questions on toxicological impact of MNP remained unclear. A major reason for that are the continued remaining knowledge gaps with regard to mechanistical understanding of MNP effects. Our work aimed at investigating MNP properties, protein interactions, and cellular effects in combination. Therefore, we characterized MNP-protein- adsorption, changes in protein structure, cellular uptake and cellular modes of action. In a first study, we studied the molecular interactions of β-lactoglobulin, a serum and storage protein, with different MNP materials1. We identified structural changes, depending on physicochemical MNP properties, using FTIR- and fluorescence spectroscopy. Furthermore, we investigated cellular uptake of MNP individually and as a complex with β-lactoglobulin and studied the effects on cell growth and viability, using colorimetric MTT testing, flow cytometry, and cell impedance measurements. MNP material properties, especially hydrophobicity, had an impact on protein folding and consequently also on cellular interactions. In a second study, we applied α-amylase, an extracellular digestive protein with enzymatic activity. Here, in addition, we investigated the influence of MNP binding on enzyme activity, using a colorimetric starch degradation assay. We observed for the most MNP, that adsorption processes resulted in a decrease of enzyme activity. Furthermore, we used Alexa633 staining to visualize MNP uptake with and without the presence of α-amylase. Taken together, this work aims to close data gaps regarding mechanistical effects of MNP on cells by investigating direct MNP-protein-interactions. Mechanistic knowledge is crucial for understanding toxicological effects of MNP, and therefore, also for the risk assessment of possible hazards on human health. T2 - 92. Jahrestagung der Deutschen Gesellschaft für Experimentelle und Klinische Pharmakologie und Toxikologie (DGPT) CY - Düsseldorf, Germany DA - 17.03.2026 KW - Microplastics KW - Nanoplastics PY - 2026 AN - OPUS4-65667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -