Biodegradable PHBV Polymer-Based Scaffolds for Bone Tissue Engineering - Biodegradable Polymer-Based Scaffolds for Bone Tissue Engineering - page 54

Fig. 3.11 Plot of ln
(molecular weight, kDa) and
degradation time (wk) at
37 °C for 24 weeks (Sultana
and Khan 2012 )
Fig. 3.12 Weight loss of
PHBV scaffolds after in vitro
degradation for 6 weeks:
( A ) 78 % porosity; ( B ) 88 %
porosity
dropped significantly from 24 to 44 weeks after in vitro degradation. The average
molecular weight of as-fabricated PHBV scaffold was 229 kDa. After the scaffold
immersion in PBS for 12, 14 and 44 weeks, it decreased to 212, 194, and 121 kDa,
respectively.
The logarithm of molecular weight loss does not fall linearly over 44 weeks of
time. But for the initial period up to 24 weeks, the decrease in molecular weight
followed the linear trend (Fig. 3.11 ). Here the autocatalysis reaction model can
be applied. The slope of the straight line or the rate constant was found to be
0.0067 week − 1 . It can be concluded from this result that the reaction rate is com-
paratively slower.
Figure 3.12 shows the effect of porosity on the weight loss of the scaffolds. It
was observed that the scaffolds having higher porosity (88 %) exhibited acceler-
ated weight loss than that of lower porosity (78 %). It was also observed that after
6 week, the 10 % nHA containing PHBV composite scaffold showed elevated