title: UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium.
abstract: BACKGROUND
  Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV) light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability.
  
  
  RESULTS
  Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light) were immersed in simulated body fluid (SBF) for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization.
  
  
  CONCLUSIONS
  UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite deposition may be a novel method to effectively enhance micro-roughened titanium surfaces without altering their microscale morphology.
authors.affiliation: Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA.
authors.forename: Makiko
authors.initials: M
authors.lastname: Saita
authors.affiliation: Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA; Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Yokosuka, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ikeda
authors.affiliation: Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA; Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamada
authors.affiliation: Department of Prosthodontics and Oral Rehabilitation, Kanagawa Dental University Graduate School of Dentistry, Yokosuka, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kimoto
authors.affiliation: Yokosuka-Shonan Disaster Health Emergency Research Center and ESR Laboratories, Kanagawa Dental University Graduate School of Dentistry, Yokosuka, Japan.
authors.forename: Masaichi Chang-Il
authors.initials: MC
authors.lastname: Lee
authors.affiliation: Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D001031:Apatites / Q000737:chemistry* / Q000528:radiation effects; D017209:Apoptosis / Q000528:radiation effects; D032701:Biomimetics; D002448:Cell Adhesion / Q000528:radiation effects; D002465:Cell Movement / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002478:Cells, Cultured; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000379:methods*; D010006:Osteoblasts / Q000166:cytology / Q000528:radiation effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D014025:Titanium
keywords: dental and orthopedic implants; hydrocarbon; nanotechnology; osseointegration; superhydrophilic
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