title: Mercaptocarborane-capped gold nanoparticles: electron pools and ion traps with switchable hydrophilicity.
abstract: A simple single-phase method for the preparation of ca. 2 nm gold nanoparticles capped with mercaptocarborane ligands is introduced. The resultant monolayer protected clusters (MPCs) exhibit redox-dependent solubility and readily phase transfer between water and nonpolar solvents depending on the electronic and ionic charge stored in the metal core and in the ligand shell, respectively. The particles and their properties have been characterized by high angle annular dark field imaging in a scanning transmission electron microscope, elemental analysis, centrifugal particle sizing, UV-vis and FTIR spectroscopy, and thermogravimetric analysis and by (1)H, (11)B, and (7)Li NMR spectroscopy. Cellular uptake of the MPCs by HeLa cells has been studied by TEM, and the subsequent generation of reactive oxygen species inside the cells has been evaluated by confocal fluorescence microscopy. These MPCs qualitatively showed significant toxicity and the ability to penetrate into most cell compartments with a strong tendency of finally residing inside membranes. Applications in catalysis, electrocatalysis, and biomedicine are envisaged.
authors.affiliation: Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus UAB, E-08193 Bellaterra, Spain.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Cioran
authors.forename: Ana D
authors.initials: AD
authors.lastname: Musteti
authors.forename: Francesc
authors.initials: F
authors.lastname: Teixidor
authors.forename: Željka
authors.initials: Ž
authors.lastname: Krpetić
authors.forename: Ian A
authors.initials: IA
authors.lastname: Prior
authors.forename: Qian
authors.initials: Q
authors.lastname: He
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kiely
authors.forename: Mathias
authors.initials: M
authors.lastname: Brust
authors.forename: Clara
authors.initials: C
authors.lastname: Viñas
mesh_terms: D001692:Biological Transport; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D004583:Electrons; D006046:Gold / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D017382:Reactive Oxygen Species / Q000378:metabolism; D012995:Solubility; D013438:Sulfhydryl Compounds / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D014867:Water / Q000737:chemistry
chemical_list: D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D014867:Water; D006046:Gold