Pretreatment with serum-free media enhances short-term adhesion of osteoblasts to borosilicate glass

To use a material for the construction of a bone implant or drug delivery system, it is crucial to understand how the cells of the body will react to the material, and key to that reaction is cellular adhesion. Colloid-probe atomic force microscopy (AFM) is useful for investigating these interactions because of its sensitivity, versatility and ability to measure adhesive interactions with individual cells. Cellular adhesion can be rapidly characterized by attaching a microsphere of the material to the AFM cantilever, and measuring the forces exerted during contact with the cell. We have investigated the pretreatment of borosilicate glass probes with serum-free and serum-containing media, and shown that, in the absence of serum, the measured adhesive force decreases non-linearly with increasing use, suggesting that the probe becomes coated with biological molecules such as proteins, and that the serum-free media pretreatment results in a slower decay in adhesion than seen with spheres pretreated with water alone. We discuss how this work fits into the broader understanding of the relationship between adhesive and non-adhesive proteins in determining the behavior of a surface.