CHITIN AND CHITOSAN FOR TISSUE ENGINEERING APPLICATION - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 440

Figure 23.2. SEM micrographs of chitosan sponge scaffolds. (a) The sur-
face and cross section of the CS chitosan sponge scaffold prepared by the
TIPS process and (b) the μ -CS chitosan sponge scaffold prepared by the
modified TIPS process.

water until the filtrate reached neutral pH. The resulting chitosan
sponge scaffolds were freeze-dried again under the same condi-
tions as described earlier. The chitosan sponge scaffolds were code-
named CS and μ -CS according to fabrication by the TIPS and the
modified TIPS process, respectively.
Figure 23.2 shows the morphologies of the porous chitosan
sponge scaffolds prepared by the TIPS and the modified TIPS
process.
The addition of the nonsolvent in the chitosan solution was to
make the homogeneous micropores and interconnectivity between
macropores without any surface skin layer. The modified TIPS
process is a solid-liquid-liquid separation process adding a nonsol-
ventforchitosan.Thedifferenceofthefreezingtemperatureofeach
of the components induced the liquid-liquid and the liquid-solid
phase separation via the solvent/nonsolvent/chitosan solution. The
pore diameters of the CS scaffold prepared by the TIPS process
were mainly about 80 ∼ 100 μ m. On the contrary, the pore diame-
tersofthe μ -CSscaffoldcouldbecontrolledmainlywithintherange
4 m, with a variation of the solvent/nonsolvent ratio in the

modified TIPS process. 27

∼

50

μ