Effect of Chitosan as a Dispersant on Collagen-Hydroxyapatite Composite Matrices

Purpose: Hydroxyapatite (HA) powder is difficult to disperse evenly in collagen (Col) gelatum, which can affect the properties of the final Col-HA composite. Here, we used chitosan (CS) as a dispersant in a bone matrix constructed with Col and Ca-5(PO4)(3)OH (HA), which are the main components of natural bone. Solid-liquid phase separation was used to shape a three-dimensional porous structure to support cell growth. Methods: The two bone matrices (Col-CS-HA and Col-HA) were investigated by transmission electron microscopy, scanning electron microscopy, and electron spectroscopy for chemical analysis for structural characteristics and physicochemical properties. Their ability to repair bone defects was evaluated in vivo. Results: HA particles were dispersed in Col gelatum evenly by mixing with CS gelatum. The surface morphology and three-dimensional structure of the matrix became more regular, which improved cell growth. After CS modification, the percentage of C-N groups increased to 6.40% and C-OH groups increased from 1.05% to 6.92%. The total amount of nonpolar groups (C-C groups and C-H groups) decreased from 82.48% to 74.05%. The vitrification and denaturation temperatures increased from 40.59 degrees C and 106.36 degrees C, respectively, to 42.23 degrees C and 111.04 degrees C, respectively. Conclusion: CS modified the surface chemistry to create a favorable environment for osteoblast adhesion and proliferation in vivo, which would accelerate the process of bone regeneration. The Col-CS-HA matrix possessed superior biological and mechanical properties for bone defect repair.