Synthesis of bio-functionalized three-dimensional titania nanofibrous 3 using femtosecond laser ablation

The primary objective of current tissue regeneration research is to synthesize nano-based platforms that 24 can induce guided, controlled, and rapid healing. Titanium nanotubes have been extensively considered 25 as a new biomaterial for biosensors, implants, cell growth, tissue engineering, and drug delivery systems. 26 However, cell adhesion to nanotubes is poor due to their chemical inertness, as well as the one-dimen- 27 sional structure, and surface modification is required to enhance nanotube–cell interaction. While there 28 have been a considerable number of studies on growing titanium nanotubes, synthesizing a three-dimen- 29 sional (3-D) nano-architecture which can act as a growth support platform for bone and stem cells has 30 not been reported so far. Therefore, we present a novel technique to synthesize and grow 3-D titania 31 interwoven nanofibrous structures on a titanium substrate using femtosecond laser irradiation under 32 ambient conditions. This surface architecture incorporate the functions of 3-D nano-scaled topography 33 and modified chemical properties to improve osseointegration while at the same time leaving space to 34 deliver other functional agents. The results indicate that laser pulse repetition can control the density 35 and pore size of engineered nanofibrous structures. In vitro experiments reveal that the titania nanofi- 36 brous architecture possesses excellent bioactivity and can induce rapid, uniform, and controllable 37 bone-like apatite precipitation once immersed in simulated body fluid (SBF). This approach to synthesiz- 38 ing 3-D titania nanofibrous structures suggests considerable promise for the promotion of Ti interfacial 39 properties to develop new functional biomaterials for various biomedical applications.