title: Modulation of the nanometer pore size improves magnesium adsorption into mesoporous titania coatings and promotes bone morphogenic protein 4 expression in adhering osteoblasts.
abstract: Mesoporous (MP) titania films used as implant coatings have recently been considered as release systems for controlled administration of magnesium to enhance initial osteoblast proliferation in vitro. Tuning of the pore size in such titania films is aimed at increasing the osteogenic potential through effects on the total loading capacity and the release profile of magnesium.
  
  
  
  In this study, evaporation-induced self-assembly (EISA) was used with different structure-directing agents to form three mesoporous films with average pore sizes of 2nm (MP1), 6nm (MP2) and 7nm (MP3). Mg adsorption and release was monitored using quartz crystal microbalance with dissipation (QCM-D). The film surfaces were characterized with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The effect of different Mg release on osteogenesis was investigated in human fetal osteoblasts (hFOB) using pre-designed osteogenesis arrays and real-time polymerase chain reaction (RT-PCR).
  
  
  
  Results showed a sustained release from all the films investigated, with higher magnesium adsorption into MP1 and MP3 films. No significant differences were observed in the surface nanotopography of the films, either with or without the presence of magnesium. MP3 films (7nm pore size) had the greatest effect on osteogenesis, up-regulating 15 bone-related genes after 1 week of hFOB growth and significantly promoting bone morphogenic protein (BMP4) expression after 3 weeks of growth.
  
  
  
  The findings indicate that the increase in pore width on the nano scale significantly enhanced the bioactivity of the mesoporous coating, thus accelerating osteogenesis without creating differences in surface roughness.
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Sweden. Electronic address: francesca.cecchinato@mah.se.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cecchinato
authors.affiliation: Department of Chemistry and Chemical Engineering, Applied Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Saba
authors.initials: S
authors.lastname: Atefyekta
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Sweden.
authors.forename: Ann
authors.initials: A
authors.lastname: Wennerberg
authors.affiliation: Department of Chemistry and Chemical Engineering, Applied Chemistry, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Andersson
authors.affiliation: Department of Prosthodontics, Faculty of Odontology, Malmö University, Sweden; Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Jimbo
authors.affiliation: Department of Oral Biology, Faculty of Odontology, Malmö University, Sweden.
authors.forename: Julia R
authors.initials: JR
authors.lastname: Davies
mesh_terms: D000327:Adsorption; D055415:Bone Morphogenetic Protein 4 / Q000378:metabolism*; D006801:Humans; D008274:Magnesium; D010006:Osteoblasts; D013499:Surface Properties; D014025:Titanium
chemical_list: D055415:Bone Morphogenetic Protein 4; C009495:titanium dioxide; D014025:Titanium; D008274:Magnesium
keywords: Magnesium release; Mesoporous titania films; Osteogenesis; Pore size; Titanium implant