Nanostructured Selenium – A Novel Biologically-Inspired Material for Antibacterial Medical Device Applications - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 203

bacterium commonly found in numerous infections. These infections can
be serious when they occur on surgical wounds, in the bloodstream, or in
the lungs. Each year, there are 11 million outpatient/emergency room vis-
its and 464,000 hospital admissions in the US alone due to Staphylococcus
aureus infections [22]. Staphylococcus aureus have been found on a wide
range of medical devices including prosthetic heart valves, central venous
catheters, urinary catheters, orthopedic prostheses, penile prostheses,
contact lenses, endocarditis, otitis media, osteomyelitis, and sinusitis [23].
Therefore, it is signifi cant to develop a method to prevent bacteria from
attaching on the surface of today's medical devices. The use of antibiotics
is not a strategy that is working, nor is it a natural biomimetic approach
towards decreasing bacteria function.

8.2 Nanomaterials for Antibacterial Implant

Applications

A common method to treat implant infection is though systemic antibiotic
therapy. However, this method has not shown satisfactory results to date.
For example, systemic antibiotic (vancomycin and gentamicin) adminis-
tration alone without catheter removal is only 22 to 37% effective in treat-
ing blood infection associated with using long-term (more than 2 weeks)
central venous catheters. In addition, this mode of antibiotic administra-
tion has the disadvantage of causing side effects and creating a pool of
antibiotic-resistant bacteria. Another treatment method is the local deliv-
ery of antibiotics. In this method, antibiotic molecules are incorporated (for
example, by adsorption or impregnation) onto the surface or into the coat-
ings on implants so that they will slowly release locally over an extended
period of time after implantation. Because of the use of antibiotics, this
method also has signifi cant drawbacks including ineffectiveness against
antibiotic-resistant bacteria (such as methicillin-resistant Staphylococcus
aureus or MRSA, important bacterium that infects all implants). An emerg-
ing approach to prevent implant infection is engineering raw implant sur-
faces to resist bacterial attachment and colonization. Since the implant
surface itself is an important source of infection and bacterial adhesion to
the implant surface and is important in the pathogenesis of infection, the
most promising and straightforward strategy towards decreasing infec-
tion is to fabricate implant materials that resist bacteria attachment [24].
However, currently materials used as implants have been shown to be
ineffective in resisting bacterial infection [25-27].
In recent years, nanomaterials have drawn increasing attention from
many researchers because these materials exhibit special properties stem-
ming from their biologically-inspired nanoscale dimensions, which are
different compared with conventional or bulk materials. An important