Biocompatible nano-ripples structured surfaces induced by femtosecond laser to rebel bacterial colonization and biofilm formation

Structured surfaces with both anti-bacterial capability and biocompatibility are essential to medical devices including orthopedic implants. Over the past few years, numerous studies indicated that nanostructures such as nanotubes, nanowires, nano-pillars and nano-ripples were capable of repelling or killing bacteria, while the morphology and dimensions of the nanostructures showed essential influence on the adhesion and proliferation of cells. The long-term functionalities of implants depend on their reliable anti-bacterial performance at the same time enhanced biocompatibility. However, researches covering both these two aspects are still very limited. In this paper, we applied one-step femtosecond laser irradiation to produce three types of nano-ripples, and to investigate their anti-bacterial behavior and their biocompatibility. Our results demonstrate that all the three types of nano-ripples are capable of preventing bacterial colonization and biofilm formation, with their anti-bacteria rates towards E. coli respectively 43%, 49% and 56%. Meanwhile, the femtosecond laser induced nano-ripples exhibit good rat mesenchymal stem cells (MSCs) proliferation capacity and spreading performance, and the nano-ripples affect significantly the orientation of MSCs. The results offer valuable information and potentials on the anti-bacteria and biocompatibility of nanostructures.