Biomedical Engineering Reference
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Fig. 1.3 Bioactive scaffolds obtained by surface mineralization via SBF treatment: cross section
images of apatite crystal coating onto the pore surface, particularly of globular apatite crystals
( upper square ) and EDS spectra for Ca and P detection ( bottom square )
polymers like Hyaluronic Acid derivate (HYAFF11 ® ). Indeed, HYAFF11 ®
dissolves in water solution only after few weeks of treatment, showing a partial
de-esterification in the presence of basic pH. In particular, Campoccia et al. [ 6 ]
have demonstrated that benzyl ester HYAFF11 ® underwent a spontaneous
hydrolytic degradation of the ester bonds even in the absence of any enzymatic
activity with a complete dissolution just after 1 week. This explains the relevant
effect of esterification degree on the degradation mechanisms as well as on the
hydrophilic behavior of the final material. Indeed, as the esterification degree
increases, polymer chains become progressively less flexible and hydrated, but
also more rigid and stable, limiting the hydrolytic attacks which act as more
active nucleation initiation sites than microscale particles. In this case, Kokubo-
like strategies rapidly fail due to a lack of crystal deposition in used experimen-
tal window time. It means that a drastic reduction of exposure time is mandatory
to prevent a catastrophic uncontrolled material loss during the conditioning via
SBF solution. Some authors have also demonstrated that organic polymers can
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