title: Assessing the Intracellular Integrity of Phosphine-Stabilized Ultrasmall Cytotoxic Gold Nanoparticles Enabled by Fluorescence Labeling.
abstract: As the size of nanoparticles (NPs) is in the range of biological molecules and subcellular structures, they provide new perspectives in biomedicine. This work presents studies concerning the cellular uptake and distribution of phosphine-stabilized cytotoxic 1.4 nm sized AuNPs and their probable degradation during this process. Therefore, ultrasmall phosphine-stabilized AuNPs are modified by linking a fluorophore covalently to the ligand shell. Monitoring the fluorescence on a cellular level by means of flow cytometry and confocal laser scanning microscopy allows determining the fate of the ligand shell during AuNP cell internalization, due to the fact that the fluorescence of a fluorophore bound near to the AuNP surface is quenched. Cell fractionation is conducted in order to quantify the AuNP content at the cell membrane, in the cytoplasm, and the cell nucleus. The incubation of cells with the fluorophore-modified AuNPs reveals a partial loss of the ligand shell upon AuNP cell interaction, evident by the emerging fluorescence signal. This loss is the precondition to unfold high AuNP cytotoxicity. Together with their significantly different biodistribution and enhanced circulation times compared to larger AuNPs, the findings demonstrate the high potential of ultrasmall AuNPs for drug development or therapy.
authors.affiliation: JARA-FIT and Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Broda
authors.affiliation: Institute of Biochemistry and Molecular Biology, University Hospital Aachen, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Küster
authors.affiliation: JARA-FIT and Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Westhues
authors.affiliation: Institute of Biochemistry and Molecular Biology, University Hospital Aachen, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Fahrenkamp
authors.affiliation: Department of Nuclear Medicine, University Hospital Aachen, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Andreas T J
authors.initials: AT
authors.lastname: Vogg
authors.affiliation: Institute for Laboratory Animal Science, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Steitz
authors.affiliation: Department of Nuclear Medicine, University Hospital Aachen, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Felix M
authors.initials: FM
authors.lastname: Mottaghy
authors.affiliation: Institute of Biochemistry and Molecular Biology, University Hospital Aachen, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Müller-Newen
authors.affiliation: JARA-FIT and Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Simon
mesh_terms: D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects; D005453:Fluorescence; D006046:Gold / Q000378:metabolism*; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D010316:Particle Size; D010720:Phosphines / Q000378:metabolism*; D013499:Surface Properties; D014018:Tissue Distribution
chemical_list: D010720:Phosphines; D006046:Gold; C044646:phosphine
keywords: TPPMS; cellular uptake; fluorescence; gold nanoparticles