title: Nanosize and vitality: TiO2 nanotube diameter directs cell fate.
abstract: We generated, on titanium surfaces, self-assembled layers of vertically oriented TiO2 nanotubes with defined diameters between 15 and 100 nm and show that adhesion, spreading, growth, and differentiation of mesenchymal stem cells are critically dependent on the tube diameter. A spacing less than 30 nm with a maximum at 15 nm provided an effective length scale for accelerated integrin clustering/focal contact formation and strongly enhances cellular activities compared to smooth TiO2 surfaces. Cell adhesion and spreading were severely impaired on nanotube layers with a tube diameter larger than 50 nm, resulting in dramatically reduced cellular activity and a high extent of programmed cell death. Thus, on a TiO2 nanotube surface, a lateral spacing geometry with openings of 30-50 nm represents a critical borderline for cell fate.
authors.affiliation: Department of Experimental Medicine I, Nikolaus Fiebiger-Center of Molecular Medicine, Germany.
authors.forename: Jung
authors.initials: J
authors.lastname: Park
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bauer
authors.forename: Klaus
authors.initials: K
authors.lastname: von der Mark
authors.forename: Patrik
authors.initials: P
authors.lastname: Schmuki
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects*; D008968:Molecular Conformation; D049329:Nanostructures / Q000008:administration & dosage* / Q000737:chemistry / Q000648:ultrastructure*; D010316:Particle Size; D051381:Rats; D014025:Titanium / Q000494:pharmacology*
chemical_list: C009495:titanium dioxide; D014025:Titanium