@article{StrasserSchrauthDembskietal.2017,
  author    = {Straßer, Marion and Schrauth, Joachim H. X. and Dembski, Sofia and Haddad, Daniel and Ahrens, Bernd and Schweizer, Stefan and Christ, Bastian and Cubukova, Alevtina and Metzger, Marco and Walles, Heike and Jakob, Peter M. and Sextl, Gerhard},
  title     = {Calcium fluoride based multifunctional nanoparticles for multimodal imaging},
  series = {Beilstein Journal of Nanotechnology},
  volume    = {8},
  journal   = {Beilstein Journal of Nanotechnology},
  doi       = {10.3762/bjnano.8.148},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170657},
  pages     = {1484-1493},
  year      = {2017},
  abstract  = {New multifunctional nanoparticles (NPs) that can be used as contrast agents (CA) in different imaging techniques, such as photoluminescence (PL) microscopy and magnetic resonance imaging (MRI), open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5-10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd\(^{3+}\) ions on the surface, the NPs reduce the MR T\(_{1}\) relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg\(^{-1}\)·s\(^{-1}\). Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL\(^{-1}\) was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs are suitable for medical imaging.},
  language  = {en}
}
@article{AppeltMenzelCubukovaGuentheretal.2017,
  author    = {Appelt-Menzel, Antje and Cubukova, Alevtina and G{\"u}nther, Katharina and Edenhofer, Frank and Piontek, J{\"o}rg and Krause, Gerd and St{\"u}ber, Tanja and Walles, Heike and Neuhaus, Winfried and Metzger, Marco},
  title     = {Establishment of a Human Blood-Brain Barrier Co-culture Model Mimicking the Neurovascular Unit Using Induced Pluri- and Multipotent Stem Cells},
  series = {Stem Cell Reports},
  volume    = {8},
  journal   = {Stem Cell Reports},
  number    = {4},
  doi       = {10.1016/j.stemcr.2017.02.021},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170982},
  pages     = {894-906},
  year      = {2017},
  abstract  = {In vitro models of the human blood-brain barrier (BBB) are highly desirable for drug development. This study aims to analyze a set of ten different BBB culture models based on primary cells, human induced pluripotent stem cells (hiPSCs), and multipotent fetal neural stem cells (fNSCs). We systematically investigated the impact of astrocytes, pericytes, and NSCs on hiPSC-derived BBB endothelial cell function and gene expression. The quadruple culture models, based on these four cell types, achieved BBB characteristics including transendothelial electrical resistance (TEER) up to 2,500 Ω cm\(^{2}\) and distinct upregulation of typical BBB genes. A complex in vivo-like tight junction (TJ) network was detected by freeze-fracture and transmission electron microscopy. Treatment with claudin-specific TJ modulators caused TEER decrease, confirming the relevant role of claudin subtypes for paracellular tightness. Drug permeability tests with reference substances were performed and confirmed the suitability of the models for drug transport studies.},
  language  = {en}
}