UV-induced chemical coating of titanium surfaces with eicosapentaenoic acid

Eicosapentaenoic acid (EPA) is an n-3 polyunsaturated fatty acid (PUFA) that has been reported to have beneficial effects on bone remodeling. Coating of titanium (Ti) implant surfaces with EPA could be used to achieve better bone healing. The aim of this study was to compare methods to coat polished Ti surfaces with a thin layer of EPA, either physically adsorbed or chemically bound, the latter being produced by UV irradiation of TiO2 and EPA. Surface characterization of the coatings was achieved by FTIR, profilometry, water contact angle (CA) measurements, and scintillation counting of [14C]-EPA. UV irradiation resulted in peroxidation of EPA molecules, while Ti surfaces became amphiphilic indicating dissociation of hydroxide molecules. The amount of [14C]-EPA that remained on UV irradiated surfaces was significantly higher than on non-irradiated surfaces. Surfaces with chemically bound EPA did not affect the viability of MC3T3-E1 cellsin vitro and were able to enhance cell attachment and differentiation, as indicated by increased gene expression of osteoblast-specific markers. Our results suggest that UV light is a suitable method to bind EPA on the surface of Ti disks, to improve cell attachment and differentiation of osteoblastic cells.