Bacterial Adhesion and Interaction with Biomaterial Surfaces - Biointerfaces: Where Material Meets Biology - page 377

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Figure 13.5 AFM images of platelet-bacteria interactions on polyurethane surfaces:
(a) platelet only, (b) platelet and bacteria without plasma proteins, and
platelets and bacteria in the presence of (c) human serum albumin,
(d) fibrinogen and (e) fibronectin (a-e, image size: 50 mm 50 mm),
(f) enlarged image showing platelets adherent or entrapped with bac-
teria (Image size: 20 mm 20 mm). The bacteria-platelet aggregates are
indicated by circles.
Reproduced from Xu and Siedlecki 128 with permission from Scientific
Research Publishing.

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bacteria-platelet aggregates on polyurethane surface (Figure 13.5c) while Fg
and Fn increased the formation of aggregates (Figure 13.5d and 13.5e).
Furthermore, non-activated platelets were observed on surface in the case of
HSA while all platelets were activated in the cases of Fg and Fn. The images
with higher magnification show that the activated platelets are either ad-
hered with bacteria or entrapped in bacterial cluster, forming platelet-
bacteria aggregates (Figure 13.5f).
As described previously, bacteria-platelet interaction can be characterized
by direct or indirect interactions between bacteria and platelet. S. epidermidis
induced the platelet activation and aggregation of bacteria and platelets
without addition of plasma proteins, suggesting a direct mechanism is in-
volved. When plasma proteins (Fg and Fn) were added in solution, more
bacteria-platelet aggregates were observed on biomaterial surface, sug-
gesting both direct and indirect mechanisms involved. More aggregations of
bacteria-platelet were measured on polyurethane surface when Fn or Fg are
added in bulk solution compared to the case of proteins only pre-adsorbed
on surface. This suggests that Fg or Fn may serve as linker in interaction of
bacteria and platelets.