Polycaprolactone-based Scaffolds Fabricated Using Fused Deposition Modelling or Melt Extrusion Techniques for Bone Tissue Engineering - Biointerfaces: Where Material Meets Biology - page 232

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Figure 9.3 A macroscopic and microscopic overview of two scaffolds degrading over
time in a 5 M NaOH solution. The scaffolds are fabricated from PCL
alone and a mixture of PCL with TCP (80 : 20 wt%). Note the different
time scales.
Adapted from Lam et al. 31

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PCL bulk increases the hydrophilicity of the bulk polymer. 31 This greatly in-
creased the degradation rate of PCL-TCP scaffolds compared to PCL only
scaffold. 5,31-33 Figure 9.3 shows the macroscopic and microscopic topography
of PCL and PCL-TCP (80 : 20 wt%) when immersed in a 5 M sodium hydroxide
solution. It was determined that PCL-TCP scaffolds had a faster degradation
rate and almost completely degraded after just 48 h. In contrast, the PCL-only
scaffolds gradually degraded over a 5 week period. 31 It has long been known
that adding hydrophilic components to degradable polyesters is a method to
control degradation rates. This is important because an ideal scaffold should
degrade at a rate whereby natural tissues can regenerate and take over.
Inclusion of different amounts of TCP is potentially a way to modulate
degradation rates of scaffolds destined for different physiological regions.
This concept was taken a step further by Kim and Kim 34 They explored the
concept of functional grading on PCL-TCP composites. The TCP concen-
tration in each layer was varied (5-40 wt%). Two control groups of plain
PCL-TCP (80 : 20 and 90 : 10 wt%) without functional grading were used.
Figure 9.4 illustrates two scaffold compositions, one homogeneous mixture
and one functionally graded. 34 The structures were analysed in vitro using