The effect of surface roughness on fibroblast adhesion in vitro.

Adhesion of tissue cells to biomaterial implants is a major factor of their biocompatibility. Quantitative or qualitative adhesion measurements would therefore be useful in the screening of new implant materials. Results from a quantitative method of measuring the total cell adhesion area of cultured cells is presented. It is postulated that the more compatible the surface, the greater the amount of cell adhesion. Fibroblastic cells were cultured on discs of plastic (Thermanox), commercially pure titanium (ISO 5832/2) or steel (ISO 5832/1), as used in AO fixation plates. The cells were fixed, stained, embedded in resin and their discs removed. Backscattered electron (BSE) imaging in a scanning electron microscope displayed the stained cells within the unstained resin. Imaging at high beam energy allowed visualization of the entire cell. Low beam energy displayed the regions of cell contact with the substrate, i.e. the focal adhesion sites. Images were analyzed with an image analysis and measurement system which allowed the percentage of the cell area involved with adhesion to be calculated. Results show that the material roughness, with the materials and cells tested, does not affect the total amount of cell adhesion. Implant surface design to encourage cell adhesion and discourage bacterial adhesion is discussed.