Nanofabrication methods for improved bone implants

The hypothesis of this thesis, is that nanofeatures on the surface of an implant enhance bio-functionality. This work introduces several approaches to micro- and nano-patterning which are well-known in the MEMS and NEMS fields. Micro- and nano-engineering of materials like ceramics, polymers, silicon and titanium are presented. The work was part of the STW project NanoSurf. In the first part, micro structuring of ceramic materials, utilizing tape casting and micromoulding, techniques was found to be a useful method delivering micro-patterned bioceramics. Further, a novel nanofabrication method for ridges and grooves on biomaterials delivered highly ordered nanoscale patterns. To obtain nanofeatures on biomaterial surfaces, first Laser Interference Lithography was employed to define patterns in resist on silicon. Next the structures were transferred into silicon with multiple reactive ion etching (RIE) steps. Finally the surface features were reproduced into polymers and used for in vitro studies or copied by means of Nanoimprint lithography (NIL) onto biomedical grade titanium and etched with an optimized chlorinated plasma reactive ion etching (RIE) process. In the biological research the nanofabricated surfaces were explored in interaction with ECM proteins. Finally the nanostructures were replicated in polystyrene slabs and a series of experiments with osteoblasts was performed, showing characteristic reactions of cells on distinct surface features.