Surface terracing on ferritic stainless-steel fibres and potential relevance to in vitro cell growth

Since many natural and biological materials are cellular, often with relatively high porosity levels (although sometimes these pores are partly filled with a fluid or a soft and compliant solid in the natural state), various types of porous materials are of interest for biological applications. A key feature for such applications is the space afforded for invasion, first by cells and ultimately by osseous tissue and vasculature. The surface should be chemically and topologically suitable for cells to penetrate and interlock. There is evidence that fine scale topographic features can affect both the adhesion and ingrowth of cells. One way of creating topographic features, such as terraces, is to employ suitable heat treatments so as to expose preferentially the low surface energy crystallographic planes via surface diffusion. The topography and crystallography of surface terraces, generated on solid-state-sintered ferritic stainless-steel fibre networks, have been characterised by electron back-scattered diffraction, atomic force microscopy and scanning electron microscopy. Initial work on the effect of these fine scale topographic features on cell proliferation shows encouraging results.