Development of materials that can interactpositively with tissues is important to
regenerative medicine strategies success. Cartilage tissue engineering (TE)
scaffolding is a field of continuous evolution, and sponges derived from the
combination of polysaccharides and proteins are expected to mimic the naturally
occurring environment in the articular cartilage matrix, providing an optimum
environment for tissue growth and regeneration. Chitosan (Cht) and Bombyx
mori silk fibroin (SF) are excellent candidates for sponges design due to their
intrinsic characteristics. The present work aimed to improve the chitosan
biocompatibility through blending with Cht-SF and genipin-cross-linking.
Hydrogels, produced by cross-linking of Cht-SF, were freeze-dryed to obtain the
cross-linked chitosan/silk (CSG) sponges. Rheological and mechanical
properties, structural aspects and morphological features of CSG sponges were
evaluated. CSG sponges possess stable and ordered structures due to protein
conformation changes from alpha-helix/randomcoil to beta-sheet structure,
porous and globular-like surface morphologies, and pH/swelling dependence at
pH 3, 7.4 and 9. To evaluate sponges’ suitability for cell studies, ATDC5
chondrocyte-like cells were seeded onto CSG sponges and ATDC5 viability
(MTS assay), proliferation (DNA test), morphology (SEM analysis) and matrix
production (GAGs quantification) were assessed after 14, 21 and 28 days of
culture. ATDC5-sponge constructs showed a significant higher adhesion,
proliferation and matrix production with the time of culture when compared to
Cht, suggesting CSG sponges as potential candidates for cartilage TE
strategies. Acknowledgements. Thanks to Portuguese Foundation for Science
and Technology, STREP Project HIPPOCRATES (NMP3-CT-2003-505758) and
European NoE EXPERTISSUES (NMP3-CT-2004-500283)
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