Investigation of cell reactions to microstructured implant surfaces

Surface topography is one of the key parameters influencing cellular reactions towards artificial materials. Surfaces with defined microstructures may be useful for enhancement of the stable anchorage of transcutaneous implants in connective tissue or for prevention of epithelial downgrowth and subsequent exfoliation. Cell reactions of keratinocytes and fibroblasts were investigated on microstructured titanium experimental surfaces with alternating grooves and ridges in the range between 1–20 μm width and 0.4–2.0 μm depth. While fibroblasts displayed oriented cell growth on the structured surfaces, human keratinocytes failed to show orientation or enhanced number of focal contacts on structures in the 2–10 μm width range. In that respect, an influence of surface structure on initial cell adhesion could not be proven. fluence of a “bioactive” fibronectin (Fn) coating on adhesion and spreading of fibroblasts was tested on smooth and structured titanium model implant surfaces. Cell spreading was enhanced significantly by the fibronectin coating. Under mechanical shear stress conditions which simulated stresses during insertion of dental implants, the stimulating effects of Fn were lost on smooth surfaces due to abrasion of the coating, while complete abrasion was prevented by microstructured surfaces. The combination of microstructures with “bioactive” coatings may be used to trigger specific cell responses in areas of the implant surface with different functionality. on and growth of different cell types on microstructured surfaces was investigated by a modified technique at the electron microscopy (EM) level. The approach allows the detection of adhesion molecules in the different membrane domains by immunocytochemical gold labelling techniques. Preliminary results with this new technique suggest that vinculin is localized in the grooves rather than on the ridges in our model system.