Biomedical Engineering Reference
In-Depth Information
Cartilage Regeneration
Because of its negative charge, HA can be used with positively-charged
molecules to build layer-by-layer assemblies. Such a polyelectrolyte
multilayer film was produced from HA and poly-L-lysine and used to
entrap BMP-2; the stiffness of the formed films was further varied by
covalent crosslinking using EDC chemistry [117]. The films supported
the attachment of both C2C12 myoblasts and MC3T3-E1 cells [117].
Layer-by-layer coatings have also been prepared from chitosan and
HA, for example on a polyethylene terephthalate artificial ligament,
where the coating promoted more bone formation at the graft-bone
interface and improved the biomechanical properties of the implanted
constructs [118].
2.9 Clinical Results and Market Potential
Thus far, this chapter has given many examples of HA formulations
taken through to preclinical evaluation for bone and cartilage
regeneration in animal studies. Some HA-based materials have
received regulatory approval and are available in clinical grade, and
therefore some HA scaffolds have made the translation to the clinic.
A scaffold that has been clinically tested and displayed encouraging
results for cartilage repair is Hyalograft C [119], which is a derivative
of HYAFF 11 [42, 120]. Clinical results have demonstrated the
production of a hyaline-like cartilage in lesions implanted with
Hyalograft C after 12 months [120].
Follow-up assessments of
patients after two or five years showed that 91.5% of the patients
improved according to the International Knee Documentation
Committee subjective evaluation [121]. Several other studies
have shown that Hyalograft C achieves better repair of damaged
articular cartilage compared to procedures such as microfracture
and autologous chondrocyte implantation [122-124].
For bone regeneration, clinical use of HA-based materials has
primarily focused on dental and craniofacial applications. Hyaloss, an
esterified high-MW HA, has been mixed with autologous bone to form
a gel for bone repair in postextractive defects, leading to accelerated
angiogenesis and bone remodelling after 4 months of healing [125].
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