Experimental study on the cytocompatibility of milling surface of poly-ether-ether-ketone (PEEK)

Poly-ether-ether-ketone (PEEK) is widely used in biomedical science because of its biocompatibility. However, the material is biologically inert. Many works have showed the potentiality of surface modification technique to enhance its biological performance, such as surface coating and impregnating bioactive materials into its substrate. Even so, these techniques are low efficiency or inapplicable in processing parts with complex structure. This thesis presents an experimental work of milling for the surface modification of PEEK, and its impact on the biological response is addressed. First, the influence of milling parameters on machined surface topography features is discussed based on the Taguchi method and end milling experiments. And then, the effect of the machined surface topography on the viability of fibroblasts is investigated by using cells from a mouse fibroblast L929 and the agar overlay test, MTT test. The experimental result indicated that there is a certain surface topography (characterized by S-sk = 0.011), which ensures the highest possible cells viability, but a significant decrease of L929 viability started with the surface roughness of S-a = 1.18 mu m. The axial and radial depths of cut are the two most critical factors to affect surface topography parameters. It is concluded that the milling process significantly affects surface topography of PEEK, which in turn influences the L929 viability.