Biomedical Engineering Reference
In-Depth Information
osteoconductive, and biodegradable with no need for a second
surgical operation to remove the device after healing occurred.
Both herbal extracts [467] and K
[468] might be added to
this formulation. Another research group prepared biocomposites
of cross-linked gelatin with β-TCP and both a good biocompatibility
and bone formation upon subcutaneous implantation in rats were
found [469]. Yang et al. [474] extended this to porous (porosity
~75%) β-TCP/gelatin biocomposites those also contained BMP-4.
Furthermore, cell-compatible and possessive some osteoinductive
properties porous β-TCP/alginate-gelatin hybrid scaffolds were
prepared and successfully tested
HPO
2
4
[471]. More to the point,
biocomposites of β-TCP with PLLA [462-464] and PLGC [465] were
prepared. Although β-TCP was able to counter the acidic degradation
of the polyester to some extent, it did not prevent a pH drop down
to ~6. Nevertheless, implantation of this biocomposite in beagles'
mandibular bones was successful [465]. α-TCP/gelatin formulations
are known as well [477].
Based on a self-reinforcement concept, biocomposites of TCP
with polylactides were prepared and studied using conventional
mechanical testing [480]. Resorbable scaffolds were fabricated from
such biocomposites [481]. Chitosan was also used as the matrix for
the incorporation of β-TCP by a solid/liquid phase separation of the
polymer solution and subsequent sublimation of the solvent. Due
to complexation of the functional groups of chitosan with calcium
ions of β-TCP, these biocomposites had high compressive modulus
and strength [482]. PCL/β-TCP biocomposites were developed in
other studies [483-486] and their
in vitro
degradation behavior was
systematically monitored by immersion in simulated body fluid at
37 °C [485]. To extend this topic further, PCL/β-TCP biocomposites
might be loaded by drugs [486].
Cell culture tests on β-TCP/PLLA biocomposites were reported;
the biocomposites showed no cytotoxicity and evidenced good cell
attachment to its surface [456]. An
in vitro
study with primary rat
calvarial osteoblasts showed an increased cellular activity in the
BMP-loaded samples [474]. Other researchers investigated BMP-
2-loaded porous β-TCP/gelatin biocomposites (porosity ~95%,
average pore size 180-200 µm) [487] and confirmed the precious
study. Biocomposites of β-TCP and glutaraldehyde cross-linked
gelatin were manufactured and tested
in vitro
to measure the
material cytotoxicity [470]. The experimental results revealed that
in vitro
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