Biomedical Engineering Reference
In-Depth Information
free-form fabrication. Microfilaments deposited at angles of 0° and 90° were
designated as the “simple” scaffold architecture, whereas those deposited at
angles alternating between 0°, 90°, 45°, and -45° were designated as the “com-
plex” scaffold architecture. The scaffolds were implanted into rabbit femoral
unicortical bone defects according to four treatment groups based on pore
structure and HAp coating. After implanted for 6 and 12 weeks, scaffolds
and host bone were recovered and processed for histology. The results sug-
gest that all configurations of the scaffolds integrated with the host bone
were biocompatible and thus might offer an exciting new scaffold platform
for delivery of biologicals for bone regeneration (Kim et al. 2012).
Luvizuto et al.
(2011) studied the PLLA/PGA/β-TCP biocomposite's osteo-
conductivity
in vivo
. The PLLA/PGA/β-TCP biocomposite interference screw
completely degraded, and no remnant was present 3 years after implantation
for a bone-patellar tendon-bone graft ACL reconstruction. Osteoconductivity
was confirmed in 21 of 26 screw sites (81%) and completely filled the site in 5
of 26 (19%) (Luvizuto et al. 2011). Reichert et al.
(2012) used ovine tibial defects
as the experiment mode to search the regenerative potential of medical grade
polycaprolactone-tricalcium phosphate (mPCL-TCP) and silk-hydroxyapatite
(silk-HAp) scaffolds. Defects were left untreated, then reconstructed with
autologous bone grafts (ABG) and mPCL-TCP or silk-HAp scaffolds. Animals
were observed for 12 weeks. X-ray analysis, torsion testing, and quantitative
computed tomography (M-CT) analyses were performed. The results of this
study suggest that mPCL-TCP scaffolds combined can serve as an alterna-
tive to autologous bone grafting in long bone defect regeneration. The com-
bination of mPCL-TCP with osteogenic cells or growth factors represents an
attractive means to further enhance bone formation (Reichert et al. 2012).
Silk fibroin has been widely used for biomaterial studies by virtue of its
combination of mechanical properties, controllable biodegradability, and
cytocompatibility. As a material for uses within bone tissue engineering
material, 3D porous silk scaffolds are receiving more attention because of
their excellent physiochemical properties (Zhang et al. 2010). Bhumiratana et
al. (2011) introduced a HAp-silk fibroin scaffold composite to regenerate the
bone defects. The result shows that the cultivation of hMSCs in the silk/HAp
composite scaffolds under perfusion conditions led to the formation of bone-
like structures and an increase in the equilibrium of Young's modulus (up to
fourfold or eightfold over 5 or 10 weeks of cultivation, respectively) in a man-
ner that correlated with the initial HAp contents (Bhumiratana et al. 2011).
7.2.1.3 Biphasic Calcium Phosphate (BCP)
7.2.1.3.1 Particles
Roohani-Esfahani et al. (2011) coated the struts of a BCP scaffold with a
nanocomposite layer consisting of bioactive glass nanoparticles (nBG) and
polycaprolactone (PCL) (BCP/PCL-nBG) to enhance its mechanical and bio-
logical behavior. The effect of various nBG concentrations (1-90 wt%) on the
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