The effect of adhesive ligands on bacterial and fibroblast adhesions to surfaces.

The modification of medical device surface with adhesive ligands has been recently shown to be an effective means for making a bioselective surface which can inhibit bacterial adhesion while promoting host cell adhesion on device materials. Currently, the lack of quantitative correlation between the adhesion strength of bacteria, nature of adhesive ligand and adhesion kinetics of mammalian cells hinders the development of such device surface. In this study, the biophysical responses of bacteria and mammalian cells towards adhesive ligand on model device surfaces formed by the chemisorption of dopamine (a moderate antibiotic) on glass are elucidated. The effects of RGD, collagen and dopamine modification on the adhesion strength of two clinically significant bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated by the determination of minimum lateral forces for bacterial detachment and the density of adhering bacteria. The result indicates that RGD has no apparent effect on E. coli and S. aureus adhesion, while collagen reduces E. coli but enhances S. aureus. In order to assess the degree of host cell integration, the adhesion kinetics of 3T3 fibroblasts on the four surfaces was examined by confocal reflectance interference contrast microscopy (C-RICM). In contrast to the difference found in bacterial adhesion, the result indicates that both collagen and RGD significantly enhance the initial rate of deformation and adhesion energy for fibroblasts compared to those on glass and dopamine-glass. Overall, it is demonstrated that the choice of adhesive ligand is critical for designing a device surface which simultaneously minimizes bacterial adhesion and enhances host cell integrations.