Biodegradable PHBV Polymer-Based Scaffolds for Bone Tissue Engineering - Biodegradable Polymer-Based Scaffolds for Bone Tissue Engineering - page 55

Fig. 3.13 Compressive
properties for an as-fabricated
( A ) and a degraded
(20 weeks) ( B ) PHBV
scaffold specimen
Fig. 3.14 SEM micrographs of a PHBV scaffolds and b HA/PHBV scaffolds after in vitro deg-
radation in PBS at 37 °C for 44 weeks (Sultana and Khan 2012 )
weight loss (approx. 18 %) than polymer scaffolds (<10 %). Accelerated weight
loss of nHA/PHBV composite scaffolds was due to dissolution of HA in the scaf-
folds matrix (Sultana and Khan 2012 ).
Mechanical testing showed that compressive properties of PHBV scaffolds
decreased considerably after 20 weeks immersion in PBS. Compressive properties
were determined from the initial linear part of the stress-strain curves. For each spec-
imen compressive properties decreased more than 40 % after in vitro degradation for
20 weeks at 37 °C (Fig. 3.13 ). Figure 3.14 a shows the morphology of PHBV scaf-
folds after in vitro degradation in PBS at 37 °C for 44 weeks. After 44 weeks, large
pores were observed in the PHBV scaffolds. Figure 3.14 b shows the morphological
change of nHA/PHBV composite scaffolds containing 10 % of HA after degradation
tests. After 44 weeks in PBS, major morphological changes were detected for com-
posite scaffolds. After immersion in PBS, the pore walls were found to be collapsed
in the composite scaffolds, which were not observed in the pure PHBV scaffolds.