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for bone tissue regeneration because of the excellent formation at the implantation site. The formation of
[18]
combination of bioactivity and osteoconductivity of biofilm takes place in several stages, starting with rapid
bioceramics with the flexibility and shape controllability surface attachment, followed by multilayered cellular
of polymers. Such nanocomposites are also able to closely proliferation and intercellular adhesion in an extracellular
mimic the microstructure of bone. These composites polysaccharide matrix. Biofilms are resistant to both the
[19]
have shown a better cell response than conventional immune response and systemic antibiotic therapies.
composites, depending on different factors, such as Different surface modification strategies for orthopedic
material composition, fabrication method, microstructure implants have been investigated, including (a) the addition
and mechanical properties of the composites, among of materials with desired functions to the surface; (b) the
others. Nonbiodegradable polymers have been used conversion of the existing surface into more desirable
in bone tissue engineering for their better mechanical chemistries and/or topographies; and (c) the removal of
properties and chemical stability than biodegradable material from the existing surface to create new relevant
polymers. However, some of these polymers, such as topographies. The latter, which was tested during in vitro
[20]
polyethylene, polypropylene and poly (etherether ketone), studies, provides the surface with a specific roughness to
demonstrate severe immune responses.
promote osteoblast proliferation and cell adhesion.
Bioceramic/natural polymer nanocomposites for Coating metal implants with a bactericidal film would
bone regeneration inhibit bacteria from colonizing implant surfaces and
Natural biopolymers (e.g. chitosan, collagen, HA, provide a high antibiotic concentration in a local region
silk fibroin, and calcium phosphate) are currently of commonly known as a nidus for bacterial infection.
[21]
interest in tissue engineering because their biological Different surface modifications and coating techniques
recognition may positively support cell adhesion and can be used, such as direct impregnation with antibiotics
function. However, these polymers have poor mechanical and immobilization of an antimicrobial agent in a matrix
properties. HA-reinforced natural polymers exhibit much capable of binding to different surfaces, as well as
[22]
better mechanical and biological properties, and thus may coating with antimicrobial, active metals such as copper
resolve many of these difficulties.
and silver, nitric oxide-releasing materials and
[24]
[23]
Carbon nanotube/polymer nanocomposites for titanium dioxide films. [25]
bone regeneration Ainslie et al. have shown in vitro that nanostructured
[26]
Carbon nanotubes (CNTs) have excellent mechanical surfaces display reduced inflammation in comparison
properties, a highly specific surface area and a low with a respective flat control. Controlled drug release
density, which makes them ideal for the fabrication of from the surfaces of implanted medical devices coated
tissue engineering scaffolds with polymers. The addition with nanostructured films is expected to yield additional
of CNTs to a polymer helps cell growth and promotes advantages over conventional coatings. However, so
cell attachment, proliferation and differentiation. The far this approach has gained limited clinical use for
cytotoxicity of CNTs is still obscure, but their toxicity can orthopedic coatings.
be reduced when incorporated into a polymeric matrix,
[21]
thus making it possible to fabricate CNT – polymer Li et al. developed biodegradable polypeptide multilayer
nanocomposites for bone tissue engineering. However, nanofilms to potentially serve as antibiotic carriers at
the long-term toxicity of CNTs in human tissue and their the implant–tissue interface. They demonstrated that
influence on bone remodeling need further investigation. polypeptide multilayer nanofilms, with or without
cefazolin, have antibacterial activity against organisms
IMPLANT‑ASSOCIATED INFECTION frequently associated with osteomyelitis, and may improve
AND NANOTECHNOLOGY bone healing through improving osteoblast cell adhesion,
viability, and proliferation.

[27]
Implant-associated infection is one of the most serious Etienne et al. developed a strategy based on the
complications in orthopedic surgery. Bone infections insertion of an antimicrobial peptide (defensin) into
associated with foreign body materials are especially polyelectrolyte multilayer films built by the alternate
difficult to treat. Removal of the infected implants, deposition of polyanions and polycations. Examination
long-term systemic antibiotic therapy, and multiple of Escherichia coli D22 growth at the surface of
revisions with radical debridement are frequently defensin-functionalized films revealed 98% inhibition when
required. [14-16] The consequences of infection can be positively charged poly (l-lysine) was the outermost layer
devastating and may lead to prolonged hospitalization, of the film, owing to the interaction of the bacteria with
poor functional outcome, sepsis, and even amputation. [17] the positively charged ends of the film.
Implant-associated infections are the result of bacterial Diamond nanoparticles or nanodiamonds (ND) have
adhesion to an implant surface and subsequent biofilm recently gained significant attention for local drug release

Plast Aesthet Res || Vol 1 || Issue 1 || Jun 2014 7