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in the form of coatings. Recent studies of cell viability, The development of nanofibers has enhanced the scope
such as the production of luminescent adenosine 5’ of fabricating scaffolds to mimic the architecture of
triphosphate, have shown that ND are not toxic to a natural human tissues at nanoscale. The high porosity of
variety of cell types. Huang et al. have examined nanofiber scaffolds provides more structural space for cell
[29]
[28]
the cytotoxicity and anti-inflammatory response of accommodation and facilitates the efficient exchange of
dexamethasone-loaded ND nanofilms in vivo and found nutrients and metabolic waste between a scaffold and its
that the nanofilms are non-apoptotic and non-cytotoxic, environment.
with efficient drug-eluting characteristics, thus being of A crucial point for the success of a scaffold, especially
great interest as novel implant coatings.
in bone tissue engineering, is a combination of the
Rauschmann et al. have developed a bioresorbable structural/mechanical properties of a polymer structure
[30]
composite of calcium sulfate and nanoparticulate HA and biological activity, both of which play a critical role
for the local delivery of antibiotics to tackle bone in cell seeding, proliferation, and new tissue formation.
infection. No in vitro cytotoxicity was noticed, and the The interest in temporary substitutes is that they provide
composite material exhibited better biocompatibility mechanical support until the tissue has regenerated and
than pure calcium phosphate. Owing to its high porosity, remodeled itself naturally.
it revealed initial high antibiotic release followed by a Kikuchi et al. fabricated an artificial bone material having
[35]
subsequent decline, ensuring concentrations well above a bone-like nanostructure and chemical composition.
the respective minimal inhibition concentrations of Composed of HA and collagen, the bone material was
gentamicin- and vancomyin-susceptible bacteria within synthesized under biomimetic conditions through
the first 3–4 days.
self-organization mechanisms between HA and collagen.
Adams et al. have examined the release of vancomycin The nanofibrous architecture improved the features of
[31]
from thin sol-gel films deposited on titanium alloy surfaces protein adsorption, including serum fibronectin and
implanted in an animal model. The coatings exhibited vitronectin, which may mediate cell interactions with
a significant inhibiting effect against the adhesion and scaffolds. [36]
biofilm formation of Staphylococcus aureus. Recombinant human bone morphogenetic protein (rhBMP)
Active coatings for the delivery of therapeutic molecules is used to induce ectopic bone formation in skeletal and
using the advantages of nanotechnology have a bright nonskeletal sites. Many other carriers have already been
[37]
future. Implant-related microbial infection is a serious reported: β-TCP, biphasic calcium phosphate, ceramics,
threat after orthopedic surgery. The literature review has insoluble bone matrix, collagen, PLA-polyglycolic acid
revealed that an increasing volume of research is focusing copolymer, tantalum, and titanium. [38-42] Most carriers
on developing antimicrobial agents with high efficiency loaded with BMP-2 show an early burst of BMP-2 release
and controlled-release ability. This method is very efficient with a reduction in retained BMP-2 to less than 10%
because it reduces systemic toxicity and the side-effects within the first 5 days.
of parenteral antibiotics, while also yielding higher drug Previous studies, using the rabbit model of DO,
concentrations in the relevant tissues. have shown that the optimal rate of lengthening is
0.7 mm/day, twice-daily lengthening; when lengthened
[43]
THE BONE HEALING PROCESS AND faster (>1.3 mm/day) the quality of the regenerated
NANOTECHNOLOGY bone is poor. Al Ruhaimi suggested that shortening the
[44]
duration of osteodistraction by increasing the distraction
Surfaces that contain micro- and nanoscale features in a rate is unsuccessful and results in nonunion. Increasing
well-controlled, “engineered” manner significantly affect the distraction rate together with the local application
cellular and subcellular function. The optimal micro/ of drugs to the distraction site is an evolving area.
[45]
nanostructure for desired osseointegration is still a Local application of osteogenic mediators such as BMPs
subject of debate. into the distraction site is useful; however, targeting
[45]
and transcutaneous injections are current problems after
A number of novel approaches have been developed for initiation of the distraction.
the fabrication of biomaterial-based three-dimensional
scaffolds. The electrospinning method has been actively Wang et al. used a rabbit model of a 1 cm tibial bone
[32]
[46]
explored recently and offers ultrafine polymer fibers, a defect to study biomaterials in DO, to determine whether
high specific surface area, and the possibility of various this could reduce the treatment time and enhance the
modifications, including mineralization of scaffolding quality of bone formation. According to their results, the
with HA, which has been shown to reduce cellular combination of biomaterials with a DO technique could
cytotoxicity in vitro. [33,34] The features of nanofiber mats be a new and cost-effective means to reduce treatment
are morphologically similar to those of the extracellular time and enhance bone consolidation in the management
matrix of natural tissue. of larger bone defects.
8 Plast Aesthet Res || Vol 1 || Issue 1 || Jun 2014