Chitosan
scaffolds were prepared as described with slight modifications to
the protocol.24 (link) Briefly, 1% chitosan gel
was prepared by dissolving chitosan in deionized water containing
1% acetic acid under a continuous stirring condition for 48 h. The
gel was centrifuged at 3350 RCF to pellet-undissolved chitosan flakes,
and a clear supernatant was used for scaffold fabrication. The gel
was aliquoted by weight (750 or 2000 mg) in 5 or 10 mL scintillation
vials, respectively. Rapamycin (1 or 50 μg) or tetracycline
(10 or 100 μg) was added to make drug-loaded scaffolds. The
samples were vortexed thoroughly and frozen at −80 °C
for a minimum of 3 h. The samples were lyophilized for 48 h using
a freeze-dryer (TAITEC, Japan). Sterile crosslinked scaffolds were
prepared by treating the lyophilized gels with 1 mL of sterile 5%
tripolyphosphate (Merck) at pH 5 for 5 min followed by two washes
using sterile 1× PBS.
To determine the swelling characteristics,
tripolyphosphate crosslinked scaffolds were weighed and immersed in
2 mL of 1× PBS and kept at 37 °C. At various times, the
weight of the scaffold was measured after approximately 5 min of drying
to remove excess water. Following weighing, the scaffolds were immersed
in freshly replenished 1× PBS. The change in weight at every
time point was determined by normalizing the value to the original
weight of the scaffold.
scaffolds were prepared as described with slight modifications to
the protocol.24 (link) Briefly, 1% chitosan gel
was prepared by dissolving chitosan in deionized water containing
1% acetic acid under a continuous stirring condition for 48 h. The
gel was centrifuged at 3350 RCF to pellet-undissolved chitosan flakes,
and a clear supernatant was used for scaffold fabrication. The gel
was aliquoted by weight (750 or 2000 mg) in 5 or 10 mL scintillation
vials, respectively. Rapamycin (1 or 50 μg) or tetracycline
(10 or 100 μg) was added to make drug-loaded scaffolds. The
samples were vortexed thoroughly and frozen at −80 °C
for a minimum of 3 h. The samples were lyophilized for 48 h using
a freeze-dryer (TAITEC, Japan). Sterile crosslinked scaffolds were
prepared by treating the lyophilized gels with 1 mL of sterile 5%
tripolyphosphate (Merck) at pH 5 for 5 min followed by two washes
using sterile 1× PBS.
To determine the swelling characteristics,
tripolyphosphate crosslinked scaffolds were weighed and immersed in
2 mL of 1× PBS and kept at 37 °C. At various times, the
weight of the scaffold was measured after approximately 5 min of drying
to remove excess water. Following weighing, the scaffolds were immersed
in freshly replenished 1× PBS. The change in weight at every
time point was determined by normalizing the value to the original
weight of the scaffold.