title: Flow cytometry for intracellular SPION quantification: specificity and sensitivity in comparison with spectroscopic methods.
abstract: Due to their special physicochemical properties, iron nanoparticles offer new promising possibilities for biomedical applications. For bench to bedside translation of super-paramagnetic iron oxide nanoparticles (SPIONs), safety issues have to be comprehensively clarified. To understand concentration-dependent nanoparticle-mediated toxicity, the exact quantification of intracellular SPIONs by reliable methods is of great importance. In the present study, we compared three different SPION quantification methods (ultraviolet spectrophotometry, magnetic particle spectroscopy, atomic adsorption spectroscopy) and discussed the shortcomings and advantages of each method. Moreover, we used those results to evaluate the possibility to use flow cytometric technique to determine the cellular SPION content. For this purpose, we correlated the side scatter data received from flow cytometry with the actual cellular SPION amount. We showed that flow cytometry provides a rapid and reliable method to assess the cellular SPION content. Our data also demonstrate that internalization of iron oxide nanoparticles in human umbilical vein endothelial cells is strongly dependent to the SPION type and results in a dose-dependent increase of toxicity. Thus, treatment with lauric acid-coated SPIONs (SEON(LA)) resulted in a significant increase in the intensity of side scatter and toxicity, whereas SEON(LA) with an additional protein corona formed by bovine serum albumin (SEON(LA-BSA)) and commercially available Rienso(®) particles showed only a minimal increase in both side scatter intensity and cellular toxicity. The increase in side scatter was in accordance with the measurements for SPION content by the atomic adsorption spectroscopy reference method. In summary, our data show that flow cytometry analysis can be used for estimation of uptake of SPIONs by mammalian cells and provides a fast tool for scientists to evaluate the safety of nanoparticle products.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Ralf P
authors.initials: RP
authors.lastname: Friedrich
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Janko
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Poettler
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Tripal
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Zaloga
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Iwona
authors.initials: I
authors.lastname: Cicha
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany ; Department of Otorhinolaryngology, Head and Neck Surgery, Section of Phoniatrics and Pediatric Audiology, University hospital Erlangen, Erlangen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Dürr
authors.affiliation: Technische Universität Dresden, Chair of Magnetofluiddynamics, Measuring and Automation Technology, Dresden, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Nowak
authors.affiliation: Technische Universität Dresden, Chair of Magnetofluiddynamics, Measuring and Automation Technology, Dresden, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Odenbach
authors.affiliation: Physikalisch-Technische Bundesanstalt Berlin, Berlin, Germany.
authors.forename: Ioana
authors.initials: I
authors.lastname: Slabu
authors.affiliation: Physikalisch-Technische Bundesanstalt Berlin, Berlin, Germany.
authors.forename: Maik
authors.initials: M
authors.lastname: Liebl
authors.affiliation: Physikalisch-Technische Bundesanstalt Berlin, Berlin, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Trahms
authors.affiliation: Department of Radiology, Division of Diagnostic and Interventional Radiology, Experimental Radiology, University hospital Jena, Jena, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Stapf
authors.affiliation: Department of Radiology, Division of Diagnostic and Interventional Radiology, Experimental Radiology, University hospital Jena, Jena, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Hilger
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Lyer
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Section of Experimental Oncology and Nanomedicine, University hospital Erlangen, Erlangen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Alexiou
mesh_terms: D005434:Flow Cytometry / Q000379:methods*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D042541:Intracellular Space / Q000737:chemistry / Q000378:metabolism; D058185:Magnetite Nanoparticles / Q000032:analysis / Q000737:chemistry; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D058185:Magnetite Nanoparticles
keywords: intracellular superparamagnetic iron oxide nanoparticles; low cytometry; quantification; side scatter; spectroscopy