9 Laser surface modification and the tissue–implant interface

The osseointegration process around metal implants may be controlled by biomimetic design of implantable surfaces to mimic the multiscale nature of bone. The use of lasers for implant surface modification has great potential for creating hierarchical structures – from macrogeometries to site-specific nanoscale modifications. On the macroscale, features of 100–200μm are believed to be optimal for the formation of remodelled osteonal, while microscale texturing may be utilised to modulate cellular attachment and soft tissue guidance around metallic implants. Collagen, bone apatite and other biomolecules are all nanoscale structures and closely govern the mechanical properties of bone. Hierarchical structuring of implant surfaces therefore makes it possible to guide cellular recruitment and adhesion, and control the adsorption of signalling molecules, to enhance bone growth and biomechanical retention.