Mesenchymal stem cell response to UV-photofunctionalized TiO2 coated CoCrMo

Abstract

Ultraviolet (UV) photofunctionalization has been shown to be highly effective at improving the osteoconductivity of titanium and TiO₂ coated materials. We aimed to assess whether the bioactivity of TiO₂ coated cobalt chromium molybdenum (CoCrMo) could be enhanced by UV photofunctionalization of the surface TiO₂ layer. Using atmospheric pressure chemical vapour deposition (APCVD) a thin layer of anatase TiO₂ was deposited onto smooth CoCrMo discs (referred to as CCMT). Human mesenchymal stem cells (MSCs) were cultured onto CCMT substrates which had been treated with UV light for 24 hours and identical substrates which had not undergone UV treatment. UV treated CCMT promoted a superior cell response in the form of enhancing markers of cell adhesion. This included stimulating the development of larger cells with increased levels of the adhesion protein vinculin and cytoskeletal protein f-actin (p < 0.05). In addition, MSCs were shown to have superior retention to UV treated CCMT after 3 and 24 hours (p < 0.05). Other cellular processes including proliferation, attachment, migration and differentiation were not affected by UV photofunctionalization. Despite this, the enhancement in cellular adhesion alone should result in an improvement in MSC retention to implant surfaces following surgery, and as a consequence, increase MSC resistance to dislodgement from external forces such as blood flow and micro motion.