Measurement of the tensile strength of cell–biomaterial interface using the laser spallation technique

A previously developed laser spallation technique to determine the tensile strength of thin film interfaces was successfully adopted to determine the tensile strength of interfaces between three different live mammalian cells (osteoblast, chondrocyte and fibroblast) and polystyrene (untreated and fibronectin coated) and titanium surfaces. No noticeable differences in the interfacial tensile strength values were found across the three cell types on the same substrate although osteoblasts showed slightly lower adhesion strength when cultured on untreated polystyrene surfaces. Significant differences were, however, measured for cells treated on different surfaces. Use of fibronectin increased the interfacial tensile strength for all cell types, and cells bonded much better to titanium than to untreated polystyrene surfaces. Cell interfacial strength was higher when cultured with serum than in a serum-free environment. The results demonstrate the remarkable sensitivity of the laser spallation experiment in determining the effects of local interfacial microstructure and chemistry on cell adhesion.