CHITIN AND CHITOSAN FOR TISSUE ENGINEERING APPLICATION - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 444

Table23.2. Preparationconditionsanddesignationsofchitosanbead
scaffolds. 7

Sample Chitosan Butanol Acetic acid Temperature Cooling media

-15 ◦ C CS-MC15 1% - 1% MC

-30 ◦ C CS-MC30 1% - 1%

-70 ◦ C CS-MC70 1% - 1%

-196 ◦ C CS-LN2 1% - 1% LN 2

→

-70 ◦ C CS-RT70 1% - 1% RT MC

-15 ◦ C 10B-MCE15 1% 10% 1%

-30 ◦ C

MC/ether mixture

10B-MCE30 1% 10% 1%

-70 ◦ C 10B-MCE70 1% 10% 1%

-196 ◦ C 10B-LN2 1% 10% 1% LN 2

RT → -70 ◦ C 10B-RT70 1% 10% 1% MC

Abbreviation: RT, room temperature.

After five minutes, the 100-well plate containing drops of chitosan
solution in MC was moved to a -70 ◦ C deep-freezer. This procedure
slows the cooling rate of chitosan solution drops than that of chi-
tosan solution drops in a -70 ◦ C cooling media directly. After three
hours, the solidified chitosan beads were moved to a cooled, freeze-
dried glass vessel for freeze-drying. The solidified chitosan beads
werefreeze-driedat-70 ◦ Cforsixhours.Theporouschitosanbeads
were washed serially with 100%, 70%, and 50% alcohol for three
hours each and then washed with deionized water until the fil-
trate reached neutral pH. The designationof each sample is listed in
Table 23.2.
The photographs of chitosan bead scaffolds are shown in
Fig. 23.4. The chitosan bead scaffolds were round shaped and about
2mmindiameteruniformly.Figure23.5showsmorphologiesofthe
surface and cross section of the chitosan bead scaffold. The macro-
pore size of the beads was controlled by changing of the temper-
ature of the cooling medium and was increased by increasing the
temperature.
The macropore size of the CS-RT70 and 10B-RT70 chitosan
bead scaffolds prepared by the slowest cooling rate in the process
was the largest of the prepared chitosan bead scaffolds. The
bead scaffolds prepared by the modified TIPS process, showed
good interconnected micropores between macropores in scaffold