Biomedical Engineering Reference
In-Depth Information
Figure 8.12
MicroCT scanning
revealed X-ray scattering from
large agglomeration of silver
particles in nanoAg-PEEK (A),
microporous Ag-PEEK (B), Zr2k
Ag-ceramic composite (C).
Unfilled PEEK (D) was used as
a control.
antimicrobial agent. However, additional work will
be required to optimize the present techniques to
impart the antimicrobial properties of silver to PEEK
more effectively.
all the facets of bacterial adhesion to biomaterials
cannot be studied in a single experiment. Therefore,
studies must be carefully designed to answer the
questions posed. Small changes in topography or
surface chemistry can result in large differences in
bacterial adhesion in vitro and in vivo. In work from
our laboratories, we have found that changes in the
topography of PEEK due to manufacturing methods
alter bacterial adhesion by common clinical patho-
gens. Additionally, altering the surface chemistry of
PEEK for increased osseointegration by oxygen
plasma treatment leads to no change in bacterial
adhesion in the absence of a protein conditioning
film. However, the presence of a protein conditioning
film led to large differences in bacterial adhesion.
While investigating bacterial adhesion to PEEK,
care must be taken when extrapolating in vitro
results to an in vivo application. The complexity of
the in vivo environment is much greater than in
any in vitro experiment. The role of the immune
response, tissue integration, individual patient vari-
ation and the broad variation of bacteria potentially
8.5 Summary and Perspectives
Bacterial adhesion to a biomaterial is often
considered to be the event that initiates biomaterial-
associated infection. Given that the number of
biomaterial-associated infections is expected to rise
in response to an increase in implant demand,
reducing bacterial adhesion is of critical clinical
importance. This chapter has discussed topics from
the role of fundamental material properties on
bacterial adhesion in vitro, to the biological response
of the host and the generation of niches for bacterial
adhesion in vivo and, finally, to the role of antibac-
terial modifications of biomaterials.
Very few studies have focused on bacterial inter-
actions with PEEK. Because of this lack of knowl-
edge, further investigations are required. However,
