63009 2025 eng 1 12 12 253 article Elsevier BV Amsterdam 1 -- -- -- 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. Colloids and Surfaces B: Biointerfaces 10.1016/j.colsurfb.2025.114702 1873-4367 urn:nbn:de:kobv:b43-630093 true journal-article publish 12.05.2025 Creative Commons - CC BY - Namensnennung 4.0 International Helena Kieserling Holger Sieg Jasmin Heilscher Stephan Drusch Albert Braeuning Andreas Thünemann Sascha Rohn eng uncontrolled Nanoplastics eng uncontrolled Microplastics eng uncontrolled Reference materials eng uncontrolled Scattering eng uncontrolled DLS Ingenieurwissenschaften und zugeordnete Tätigkeiten Sanitär- und Kommunaltechnik; Umwelttechnik 6 Materialchemie 6.5 Synthese und Streuverfahren nanostrukturierter Materialien Umwelt Umwelt-Material-Interaktionen Material Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM Advanced Materials Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/63009/Kieserling_Colloids_and_Surfaces_B_Biointerfaces_2025_253_114702.pdf