title: Intracellular uptake and toxicity of three different Titanium particles.
abstract: BACKGROUND
  Titanium (Ti) and its alloys are used for implants and other dental materials. In this study, cytotoxicity, DNA damage, cellular uptake and size of three kinds of Ti particles were measured.
  
  
  METHODS
  Cytotoxicity for Ti microparticles (Ti-MPs, <44 μm), NiTi microparticles (NiTi-MPs, <44 μm), and Ti nanoparticles (Ti-NPs, <100 nm) in periodontal ligament (PDL)-hTERT cells was measured with XTT test. DNA damage was determined with comet assay. Particle size was measured with scanning electron microscope, intracellular uptake was determined with laser scanning confocal microscopy and transmission electron microscopy.
  
  
  RESULTS
  The EC50 values of investigated particles were: 2.8 mg/ml (Ti-NPs), 41.8 mg/ml (NiTi-MPs) and >999 mg/ml (Ti-MPs). The Olive Tail Moment (OTM) values at 1/10 EC50 were: 3.2 (Ti-NPs) and 2.2 (NiTi-MPs). An OTM of 2.2 for Ti-MPs was detected at the concentration of 6666 μg/ml. Determined sizes of investigated particles were 20-250 nm (Ti-NPs), 0.7-90 μm (NiTi-MPs) and 0.3-43 μm (Ti-MPs). The highest cellular uptake efficiency was observed with Ti-NPs, followed by Ti-MPs and NiTi-MPs. Only Ti-NPs were found in the nucleus.
  
  
  CONCLUSIONS
  Compared to Ti-MPs and NiTi-MPs, Ti-NPs induced higher cellular uptake efficiency and higher toxic potential in PDL-hTERT cells. Ni in the alloy NiTi induced an increase in the toxic potential compared to Ti-MPs.
authors.affiliation: Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr 70, 80336 Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nussbaumstr 26, 80336 Munich, Germany.
authors.forename: Xiuli
authors.initials: X
authors.lastname: He
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians-University of Munich, Pettenkoferstr 11, 80336 Munich, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Hartlieb
authors.affiliation: Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr 70, 80336 Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nussbaumstr 26, 80336 Munich, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Rothmund
authors.affiliation: Institute of Anatomy and Cell Biology, Ludwig-Maximilians-University of Munich, Pettenkoferstr 11, 80336 Munich, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Waschke
authors.affiliation: Helmholtz Zentrum München-German Research Center for Environmental Health, Cooperation Group of Comprehensive Molecular Analytics, Ingolstädter Landstr 1, 85764 Neuherberg, Germany.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wu
authors.affiliation: KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium.
authors.forename: Kirsten L
authors.initials: KL
authors.lastname: Van Landuyt
authors.affiliation: Department of Anatomy II - Neuroanatomy, Ludwig-Maximilians-University of Munich, Pettenkoferstr 11, 80336 Munich, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Milz
authors.affiliation: Research Unit Analytical Biogeochemistry, Helmholtz Zentrum Munich-German Research Center for Environmental Health (GmbH), Ingolstädter Landstr 1, 85764 Neuherberg, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Michalke
authors.affiliation: Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nussbaumstr 26, 80336 Munich, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Hickel
authors.affiliation: Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr 70, 80336 Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nussbaumstr 26, 80336 Munich, Germany.
authors.forename: Franz-Xaver
authors.initials: FX
authors.lastname: Reichl
authors.affiliation: Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr 70, 80336 Munich, Germany; Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University of Munich, Nussbaumstr 26, 80336 Munich, Germany. Electronic address: christof.hoegg@lrz.uni-muenchen.de.
authors.forename: Christof
authors.initials: C
authors.lastname: Högg
mesh_terms: D016923:Cell Death; D002470:Cell Survival; D020552:Comet Assay; D004249:DNA Damage; D003722:Dental Alloys / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000633:toxicity*; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D010513:Periodontal Ligament / Q000166:cytology*; D014025:Titanium / Q000633:toxicity*
chemical_list: D003722:Dental Alloys; D014025:Titanium
keywords: Cellular uptake; Cytotoxicity; DNA damage; Nanoparticles; Titanium