Scaffold Design for Bone Tissue Engineering: From Micrometric to Nanometric Level - Biologically Responsive Biomaterials for Tissue Engineering - page 14

hydroxylapatite clays into nanofibrous polymer matrix allows mimicking the natural
composition of the bone ECM. In particular, nano-HA particles also concur to slow
down the degradation process by neutralizing or buffering the pH changes caused by
the typical acidic degradation products of polyesters, potentially enhancing mechani-
cal and biological response of the scaffolds during in vitro and in vivo implant.
Synthetic polymers endowed to nano-sized HA particles offer a chemical cue able to
affect the cell behavior, thus catalyzing bioactivity and mineralization processes.
Although the underlying mechanism for this phenomenon is not clear, bioactive HA
particles obtained by the dissolution and precipitation of calcium and phosphate ions
out of the fiber surface layer provide to create a microenvironment that resembles the
natural bone and stimulates osteogenic differentiation of MSCs.

1.6 Conclusions

Micro- or nanostructured tissue engineering scaffolds have the potential to direct cell
destiny, as well as to regulate processes such as angiogenesis and cell migration.
Architecture and chemical cues concur to induce cells' attachment and trigger
specific cell/materials interaction mechanisms. The addition of polymer phases may
positively contribute to finely control morphology, mechanical response, degrada-
tion profile, and, as a consequence, cellular events, guiding new tissue ingrowth by
the gradual transmission of biochemical and biophysical signals, moving towards a
true mimicking of natural ECM functions.

Acknowledgments This study was supported by the Italian Research Network “TISSUENET” n.
RBPR05RSM2 and by IP STEPS EC FP6-500465.

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