title: Fluorescence investigation of the detachment of aluminum phthalocyanine molecules from aluminum phthalocyanine nanoparticles in monocytes/macrophages and skin cells and their localization in monocytes/macrophages.
abstract: BACKGROUND
  Nanoparticles made from aluminum phthalocyanine (AlPc) are non-fluorescent in the nanoparticle form. Once AlPc molecules become detached from the particle, fluorescence occurs. Preliminary work showed the benefit of using aluminum phthalocyanine nanoparticles (nAlPc) for the rating of the rejection risk of skin autografts in mice by measuring fluorescence intensities of detached AlPc. Skin autografts showing a high fluorescence intensity were finally rejected suggesting an inflammatory process. In contrast, autografts with normal autofluorescence were accepted. This work was focused on the mechanism of this finding. The aim is detecting inflammatory processes and the potential use of nAlPc for PDT as a new treatment modality.
  
  
  METHODS
  The effect of the lipopolysaccharide-stimulated monocyte/macrophage murine cell line J774A.1 on the monomerization of internalized nAlPc was tested. Further, we investigated the influence of J774A.1 cells and the normal skin cell lines L-929 or HaCaT on the dissolution of nAlPc by laser scanning microscopy and flow cytometry. Localization of AlPc molecules after uptake and dissolution of nanoparticles by the cells was surveyed.
  
  
  RESULTS
  In co-culture models composed of J774A.1 and HaCaT/L-929 cells, the AlPc fluorescence intensity in J774A.1 cells is 1.38/1.89 fold higher, respectively. According to localization measurements in J774A.1 cells it can be assumed that nAlPc is taken up via endocytosis and remains in endosomes and/or lysosomes dissolving there. Detached molecules of AlPc cause rapture of the endosomal and/or lysosomal membrane after irradiation to become quite uniformly distributed in the cytoplasm.
  
  
  CONCLUSIONS
  Evidence for monocytes/macrophages being the origin of the measured AlPc fluorescence in rejected skin autografts was confirmed.
authors.affiliation: Institut für Lasertechnologien in der Medizin und Meßtechnik, Helmholtzstr. 12, 89081 Ulm, Germany; Core Facility Konfokale und Multiphotonen Mikroskopie, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany. Electronic address: jasmin.breymayer@uni-ulm.de.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Breymayer
authors.affiliation: Core Facility Konfokale und Multiphotonen Mikroskopie, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Rück
authors.affiliation: Natural Sciences Center of A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov str. 38, bld. 5, 119991 Moscow, Russia.
authors.forename: Anastasiya V
authors.initials: AV
authors.lastname: Ryabova
authors.affiliation: Natural Sciences Center of A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilov str. 38, bld. 5, 119991 Moscow, Russia.
authors.forename: Victor B
authors.initials: VB
authors.lastname: Loschenov
authors.affiliation: Institut für Lasertechnologien in der Medizin und Meßtechnik, Helmholtzstr. 12, 89081 Ulm, Germany.
authors.forename: Rudolf W
authors.initials: RW
authors.lastname: Steiner
mesh_terms: D000818:Animals; D002460:Cell Line; D006801:Humans; D007211:Indoles / Q000737:chemistry* / Q000528:radiation effects; D015603:Keratinocytes; D008027:Light; D008264:Macrophages / Q000737:chemistry* / Q000166:cytology / Q000528:radiation effects; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D051379:Mice; D009000:Monocytes / Q000737:chemistry* / Q000166:cytology / Q000528:radiation effects; D009942:Organometallic Compounds / Q000737:chemistry* / Q000528:radiation effects; D013347:Subcellular Fractions / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; C060570:aluminum phthalocyanine
keywords: Aluminum phthalocyanine; Fluorescence diagnostics; Fluorescence microscopy; Monocytes/macrophages; Nanoparticles; Photodynamic therapy