Biomedical Engineering Reference
In-Depth Information
Fig. 1.2
Scanning electron
microscopy of PCL scaffolds
obtained by phase inversion
and salt leaching technique
In particular, the synergic combination of phase inversion/salt leaching tech-
nique and the filament winding technology allows developing composite scaffolds
incorporating polylactide (PLA) continuous fibers within a PCL matrix which sat-
isfy these requirements [
17,
18
]. The employment of highly biocompatible and
bioresorbable PCL and PLA assures the maintenance of sufficient physical and
mechanical properties for at least 6 months before their degradation. The integra-
tion of a solid porogen (i.e., sodium chloride crystals) within a 3-D polymer matrix
enables creation of an interconnected pore network with well-defined pore sizes
and shapes (Fig.
1.2
).
Tricalcium phosphate (a-TCP) powder, which is able to precipitate in calcium-
deficient hydroxyapatite (CDHA) form, is recognized by the host tissue as being
similar to natural bone apatite. Moreover, it significantly hinders the stress-shielding
phenomena associated with the use of traditional rigid metal-based implants.
Meanwhile, the continuous degradation of the implant causes a gradual load
transfer to the healing tissue, preventing the stress-shielding atrophy, with the stim-
ulation of the healing and bone remodeling. The balance between chemical compo-
sition and spatial organization of reinforcement systems allows attaining an optimal
compromise between mechanical response and bioactive potential to reproduce the
bone mECM features.
1.3.2
Multi-scale Degradation
To date, much effort has been dedicated to the design of a variety of composite
materials for tissue engineering scaffolds with tailored degradation properties.
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