title: Quantification of Al2O3nanoparticles in human cell lines applying inductively coupled plasma mass spectrometry (neb-ICP-MS, LA-ICP-MS) and flow cytometry-based methods.
abstract: In order to quantify and compare the uptake of aluminum oxide nanoparticles of three different sizes into two human cell lines (skin keratinocytes (HaCaT) and lung epithelial cells (A549)), three analytical methods were applied: digestion followed by nebulization inductively coupled plasma mass spectrometry (neb-ICP-MS), direct laser ablation ICP-MS (LA-ICP-MS), and flow cytometry. Light and electron microscopy revealed an accumulation and agglomeration of all particle types within the cell cytoplasm, whereas no particles were detected in the cell nuclei. The internalized Al2O3particles exerted no toxicity in the two cell lines after 24 h of exposure. The smallest particles with a primary particle size (xBET) of 14 nm (Alu1) showed the lowest sedimentation velocity within the cell culture media, but were calculated to have settled completely after 20 h. Alu2 (xBET= 111 nm) and Alu3 (xBET= 750 nm) were calculated to reach the cell surface after 7 h and 3 min, respectively. The internal concentrations determined with the different methods lay in a comparable range of 2-8 µg Al2O3/cm2cell layer, indicating the suitability of all methods to quantify the nanoparticle uptake. Nevertheless, particle size limitations of analytical methods using optical devices were demonstrated for LA-ICP-MS and flow cytometry. Furthermore, the consideration and comparison of particle properties as parameters for particle internalization revealed the particle size and the exposure concentration as determining factors for particle uptake.
authors.affiliation: Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Steffi
authors.initials: S
authors.lastname: Böhme
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Stärk
authors.affiliation: Department of Powder and Suspension Characterization, Fraunhofer Institute for Ceramic Technologies and Systems - IKTS, Winterbergstr. 28, 01277 Dresden, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Meißner
authors.affiliation: Centre for Translational Bone, Joint and Soft Tissue Research, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Springer
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Reemtsma
authors.affiliation: Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Dana
authors.initials: D
authors.lastname: Kühnel
authors.affiliation: Department of Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
authors.forename: Wibke
authors.initials: W
authors.lastname: Busch
keywords: Aluminum oxide; Cellular internalization; Flow cytometry; Inductively coupled plasma mass spectrometry (ICP-MS); Size dependency