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 alloyTi6Al4V. 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 fromhydrophobic to superhydrophilic. The attachment, spread, proliferation, and the expression of functional phenotype of bonemarrow-derived osteoblasts were promoted on photofunctionalized Ti6Al4V surfaces. The strength of bone-implant integrationexamined using a biomechanical push-in test in a rat femurmodel was at least 100% greater for photofunctionalizedimplants than for untreated implants. These effects were seen onboth surface types. The strength of bone-implant integration forphotofunctionalized machined implants was greater than that foruntreated roughened implants, indicating that the impact of photofunctionalization may be greater than that of surface roughening. Newly prepared Ti alloy was hydrophilic, whereas thehydrophilic status degraded with time and was converted tohydrophobic in 4 weeks. This finding uncovered biological agingof Ti alloy and allowed us to consider photofunctionalization as acountermeasure for aging. These results suggest that photofunctionalization accelerates and enhances bone-implant integrationof Ti6Al4V regardless of smooth and roughened surface features,supporting photofunctionalization as an effective and viablemeasure for improving efficacy of a wide range of Ti6Al4V-basedmaterials used in dental and orthopedic medicine. VC 2013 WileyPeriodicals, Inc. J Biomed Mater Res Part A: 102A: 3618?3630, 2014.