title: Biomolecular environment, quantification, and intracellular interaction of multifunctional magnetic SERS nanoprobes.
abstract: Multifunctional composite nanoprobes consisting of iron oxide nanoparticles linked to silver and gold nanoparticles, Ag-Magnetite and Au-Magnetite, respectively, were introduced by endocytic uptake into cultured fibroblast cells. The cells containing the non-toxic nanoprobes were shown to be displaceable in an external magnetic field and can be manipulated in microfluidic channels. The distribution of the composite nanostructures that are contained in the endosomal system is discussed on the basis of surface-enhanced Raman scattering (SERS) mapping, quantitative laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) micromapping, and cryo soft X-ray tomography (cryo soft-XRT). Cryo soft-XRT of intact, vitrified cells reveals that the composite nanoprobes form intra-endosomal aggregates. The nanoprobes provide SERS signals from the biomolecular composition of their surface in the endosomal environment. The SERS data indicate the high stability of the nanoprobes and of their plasmonic properties in the harsh environment of endosomes and lysosomes. The spectra point at the molecular composition at the surface of the Ag-Magnetite and Au-Magnetite nanostructures that is very similar to that of other composite structures, but different from the composition of pure silver and gold SERS nanoprobes used for intracellular investigations. As shown by the LA-ICP-MS data, the uptake efficiency of the magnetite composites is approximately two to three times higher than that of the pure gold and silver nanoparticles.
authors.affiliation: Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin, Germany. janina.kneipp@chemie.hu-berlin.de.
authors.forename: Tina
authors.initials: T
authors.lastname: Büchner
authors.affiliation: Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin, Germany. janina.kneipp@chemie.hu-berlin.de.
authors.forename: Daniela
authors.initials: D
authors.lastname: Drescher
authors.affiliation: Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin, Germany. janina.kneipp@chemie.hu-berlin.de and Humboldt-Universität zu Berlin, School of Analytical Sciences Adlershof (SALSA), Albert-Einstein-Str. 5-9, 12489 Berlin, Germany.
authors.forename: Virginia
authors.initials: V
authors.lastname: Merk
authors.affiliation: BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Str. 11, 12489 Berlin, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Traub
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Guttmann
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Werner
authors.affiliation: BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Str. 11, 12489 Berlin, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Jakubowski
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Schneider
authors.affiliation: Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin, Germany. janina.kneipp@chemie.hu-berlin.de.
authors.forename: Janina
authors.initials: J
authors.lastname: Kneipp