title: Uptake of functionalized, fluorescent-labeled polymeric particles in different cell lines and stem cells.
abstract: Labeling of cells with particles for in-vivo detection is interesting for various biomedical applications. The objective of this study was to evaluate the feasibility and efficiency labeling of cells with polymeric particles without the use of transfection agents. We hypothesized that surface charge would influence cellular uptake. The submicron particles were synthesized by the miniemulsion process. A fluorescent dye which served as reporter was embedded in these particles. The surface charge was varied by adjusting the amount of copolymerized monomer with amino group thus enabling to study the cellular uptake in correlation to the surface charge. Fluorescent-activated cell sorter (FACS) measurements were performed for detecting the uptake of the particles or attachment of particles in mesenchymal stem cells (MSC), and the three cell lines HeLa, Jurkat, and KG1a. These cell lines were chosen as they can serve as models for clinically interesting cellular targets. For these cell lines-with the exception of MSCs-a clear correlation of surface charge and fluorescence intensity could be shown. For an efficient uptake of the submicron particles, no transfection agents were needed. Confocal laser scanning microscopy and transmission electron microscopy (TEM) revealed differences in subcellular localization of the particles. In MSCs and HeLa particles were mostly located inside of cellular compartments resembling endosomes, while in Jurkat and KG1a, nanoparticles were predominantly located in clusters on the cell surface. Scanning electron microscopy showed microvilli to be involved in this process.
authors.affiliation: Department of Transfusion Medicine, Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, University of Ulm, Helmholtzstr. 10, 89081 Ulm, Germany.
authors.forename: Myriam Ricarda
authors.initials: MR
authors.lastname: Lorenz
authors.forename: Verena
authors.initials: V
authors.lastname: Holzapfel
authors.forename: Anna
authors.initials: A
authors.lastname: Musyanovych
authors.forename: Karin
authors.initials: K
authors.lastname: Nothelfer
authors.forename: Paul
authors.initials: P
authors.lastname: Walther
authors.forename: Hendrik
authors.initials: H
authors.lastname: Frank
authors.forename: Katharina
authors.initials: K
authors.lastname: Landfester
authors.forename: Hubert
authors.initials: H
authors.lastname: Schrezenmeier
authors.forename: Volker
authors.initials: V
authors.lastname: Mailänder
mesh_terms: D002460:Cell Line; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000737:chemistry* / Q000648:ultrastructure; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission
chemical_list: D005456:Fluorescent Dyes