Bacterial Adhesion and Interaction with Biomaterial Surfaces - Biointerfaces: Where Material Meets Biology - page 379

materials is of great interest for the potential clinical use in combating
health-care infections and thrombosis.

13.4.2 Principles of the Inhibition of Bacterial Adhesion by
Textured Surfaces
Attachment of bacteria onto a material's surface is a result of interactions
between the cell surface and materials or molecules adsorbed on a surface.
The availability of binding sites from cell surface or the material surface that
bacteria can access to contact is important for initial attachment of bacteria.
The hypothesis for the inhibition of bacterial adhesion by a textured surface
is that surface textures with sub-bacterial dimensions can reduce the ma-
terial surface area accessible to bacteria, resulting in decreased opportunity
for interaction of bacteria with the material surface or adhesive plasma
proteins (e.g., Fg and Fn) adsorbed on the material. Thus, the flow of fluid
over the material surface removes bacteria from a textured surface more
eciently than it would be from a smooth surface, and resists bacterial
adhesion and biofilm formation (Figure 13.6).
In our study, a polyurethane block co-polymer is used as the model bio-
material for modification with a textured surface since it is a primary ma-
terial used in a variety of blood-contacting medical devices due to its
excellent properties. Using a soft lithography two-stage replication molding
technique, polyurethane films were prepared with ordered arrays of pillars
with submicron dimensions, smaller than the diameter of bacterial cells. 153
One representative AFM three-dimensional (3D) topography image of poly-
urethane film with pattern of 500/500 nm (diameter/spacing of pillars) is

d n 3 r 4 n g | 3

.

(a) (b)

Figure 13.6 (a) AFM 3D topography image of textured polyurethane surfaces with

pattern of 500/500 nm (round pillar diameter/separation) (scan size
5 5 mm 2 ), and (b) schematic diagram for bacterial adhesion inhibition
by surface texturing, PP ¼ plasma proteins.
Reproduced from Xu and Siedlecki 153 with permission from Elsevier.