title: Photofunctionalization increases the bioactivity and osteoconductivity of the titanium alloy Ti6Al4V.
abstract: This study examined the effect of photofunctionalization on bioactivity and osteoconductivity of titanium alloy Ti6Al4V. We also tested a hypothesis that the effect of photofunctionalization is as substantial as the one of surface roughening. Two different surface morphology, a roughened surface (sandblasted and acid-etched surface) and relatively smooth surface (machined surface), was tested. Ti6Al4V samples were photofunctionalized with UV light for 15 min using a photo device. Photofunctionalization converted Ti6Al4V surfaces from hydrophobic to superhydrophilic. The attachment, spread, proliferation, and the expression of functional phenotype of bone marrow-derived osteoblasts were promoted on photofunctionalized Ti6Al4V surfaces. The strength of bone-implant integration examined using a biomechanical push-in test in a rat femur model was at least 100% greater for photofunctionalized implants than for untreated implants. These effects were seen on both surface types. The strength of bone-implant integration for photofunctionalized machined implants was greater than that for untreated roughened implants, indicating that the impact of photofunctionalization may be greater than that of surface roughening. Newly prepared Ti alloy was hydrophilic, whereas the hydrophilic status degraded with time and was converted to hydrophobic in 4 weeks. This finding uncovered biological aging of Ti alloy and allowed us to consider photofunctionalization as a countermeasure for aging. These results suggest that photofunctionalization accelerates and enhances bone-implant integration of Ti6Al4V regardless of smooth and roughened surface features, supporting photofunctionalization as an effective and viable measure for improving efficacy of a wide range of Ti6Al4V-based materials used in dental and orthopedic medicine.
authors.affiliation: Laboratory of Bone and Implant Sciences (LBIS) Weintraub Center for Reconstructive Biotechnology Division of Advanced Prosthodontics, UCLA School of Dentistry, Los Angeles, California.
authors.forename: Hajime
authors.initials: H
authors.lastname: Minamikawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ikeda
authors.forename: Wael
authors.initials: W
authors.lastname: Att
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hagiwara
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirota
authors.forename: Masako
authors.initials: M
authors.lastname: Tabuchi
authors.forename: Hideki
authors.initials: H
authors.lastname: Aita
authors.forename: Wonhee
authors.initials: W
authors.lastname: Park
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000497:Alloys; D000818:Animals; D001861:Bone Regeneration / Q000528:radiation effects*; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D020007:Implants, Experimental; D008297:Male; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration / Q000187:drug effects; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D010641:Phenotype; D017207:Rats, Sprague-Dawley; D013052:Spectrometry, X-Ray Emission; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology* / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000497:Alloys; C031462:titanium alloy (TiAl6V4); D014025:Titanium; D000469:Alkaline Phosphatase; D002118:Calcium
keywords: UV; biological aging; bone-implant integration; hydrophilicity; osseointegration