A new injectable in situ forming hydroxyapatite and thermosensitive chitosan gel promoted by Na2CO3

Abstract

A new injectable in situ forming hydroxyapatite and thermosensitive chitosan gel (chitosan/HA/Na₂CO₃ gel) promoted by Na₂CO₃ was preliminarily synthesized. This study was the first to use Na₂CO₃ as coagulant to construct the chitosan thermosensitive gel. The sol–gel phase transition, degradation, and morphology of the gel were examined. We found that chitosan/HA/Na₂CO₃ sol with 1.4% Na₂CO₃ has a suitable gelation time (9 min) and degradation rate. SEM images of the dried gel show a porous netlike framework. TEM, EDS, and XRD were combined to confirm the presence of hydroxyapatite. In vitro cell culture was performed by using rat bone mesenchymal stem cells (rBMSCs). rBMSCs survived well on the chitosan gel scaffold that formed in vitro and in vivo, indicating that the chitosan gel was a suitable substrate for the attachment and proliferation of rBMSCs. Subcutaneous implantation of the chitosan gel formed in situ into a nude mouse revealed that the chitosan gel loaded with rBMSCs could lead to angiogenesis.