Probing the nanoadhesion of Streptococcus sanguinis to titanium implant surfaces by AFM

International Journal of Nanomedicine

s titanium (Ti) continues to be utilized in great extent for the fabrication of artificial implants, it is important to understand the crucial bacterium–Ti interaction occurring during the initial phases of biofilm formation. By employing a single-cell force spectroscopy technique, the nanoadhesive interactions between the early-colonizing Streptococcus sanguinis and a clinically analogous smooth Ti substrate were explored

SCFS of living S. sanguinis cells proved to be a reliable way to characterize the nature of their adhesion onto clinically analogous smooth Ti surfaces at different contact times. Within the limitations of this study, it was possible to characterize and decouple adhesion forces between an S. sanguinis bacterial probe and a clinically analogous Ti implant surface. Values for both adhesion force and adhesion work were found to increase at higher surface delays and were significantly higher than the poly-DOPA controls, and thus believed to directly reflect the interaction between immobilized S. sanguinis cells and the Ti substrate. Predicted contour lengths for single-unbinding events are consistent with previous reports in literature for similar streptococcal strains, and force-decoupling at 60 seconds contact times demonstrated that S. sanguinis attaches to Ti surfaces predominantly though specific short-range adhesive forces. Therefore, as Ti substrates employed in this study were found to be hydrophilic, we suggest hydrogen bonding as the principal driving force in the initial phase of streptococcal adhesion to Ti surfaces. Finally, the addition of a CHX solution to the system generated increased values for both adhesion force and work parameters. Hopefully, these results will give new insight on the use of SCFS for the study of bacterial adhesion onto clinically representative biomaterial surfaces.

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