Probing the nanoadhesion of Streptococcus sanguinis to titanium implant surfaces by atomic force microscopy
Year: 2016
Journal: Int. J. Nanomed.
Authors: Aguayo, S; Donos, N; Spratt, D; Bozec, L
As 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. Mean adhesion forces between S. sanguinis and Ti were found to be 0.32 +/- 0.00, 1.07 +/- 0.06, and 4.85 +/- 0.56 nN for 0, 1, and 60 seconds contact times, respectively; while adhesion work values were reported at 19.28 +/- 2.38, 104.60 +/- 7.02, and 1,317.26 +/- 197.69 aJ for 0, 1, and 60 seconds, respectively. At 60 seconds surface delays, minor-rupture events were modeled with the worm-like chain model yielding an average contour length of 668 +/- 12 nm. The mean force for S. sanguinis minor-detachment events was 1.84 +/- 0.64 nN, and Poisson analysis decoupled this value into a short-range force component of -1.60 +/- 0.34 nN and a long-range force component of -0.55 +/- 0.47 nN. Furthermore, a solution of 2 mg/mL chlorhexidine was found to increase adhesion between the bacterial probe and substrate. Overall, single-cell force spectroscopy of living S. sanguinis cells proved to be a reliable way to characterize early-bacterial adhesion onto machined Ti implant surfaces at the nanoscale.
