Hydroxyapatite / Beta-phosphate And Calcium / Chitin And Hydroxyapatite / Beta-tricalcium Phosphate / Sodium Alginate Scaffold

HAP is the main component of the bone and has good biocompatibility, bioactivities and bone conductibility. Nevertheless, the slow degradability, weak inducement and big brittleness limit its application. In this paper, chitin and sodium alginate were used to improve properties of the HAP/8-TCP scaffold:1. Firstly, HAP powder was adopted as raw material to form ceramic slurry, the HAP /β-TCP porous scaffold was prepared via polymer foam impregnation and micro-wave foaming. The prepared method of the HAP/β-TCP/Chitin composite scaffold was investigated. The influences of the content of chitin and remaining salt and the time of dilution to porosity and intensity of the scaffold were taken into account. Further, the component, microstructure, element composition and distribution of pore size of the porous scaffold material were systematically characterized via XRD, SEM, EDS and metallographic method etc. Afterwards, the cell biocompatibility of the HAP /β-TCP/Chitin compound scaffold and the HAP /β-TCP porous scaffold was investigated by co-culturing with human bone marrow-derived mesenchymal stem cells in vitro. The factors that affected the cell biocompatibility were also analyzed.It was shown that the HAP /β-TCP/Chitin composite scaffold with porosity of 70%-80% and intensity of 0.9MPa-1.5MPa could be prepared when the content of chitin and remaining salt were between 35% and 50% and the time of dilution of salt was 0.5 hour. The porosity of the HAP /β-TCP/Chitin compound scaffold was reduced and the intensity of the HAP /β-TCP/Chitin composite scaffold was increased with the increase of chitin and salt. With the increase of dilution time of salt, the porosity of the HAP /β-TCP/Chitin compound scaffold was increased and the intensity of the HAP /β-TCP/Chitin composite scaffold was reduced. It was shown that the HAP/B-TCP/Chitin scaffold has better stem cells biocompatibility than the HAP/B-TCP scaffold by co-culturing with bone marrow-derived mesenchymal stem cells in vitro. The addition of chitin increased the surface coarseness of the scaffoldmaterial. Molecular structure of chitin had acetyl and amidogen so that the hydrophilicity of the scaffold was improved. Laminin was adsorbed on the surface of the scaffold. These factors made bone marrow-derived mesenchymal stem cells attached to the composite scaffold and grew well. When the PH of the composite scaffold was 7.0-7.2, the content of chitin was between 9% and 13% and the content of salt was less than 40%, the HAP/6-TCP/Chitin compound scaffold adapted to the adhesion and the growth of stem cells.2. Secondly, the preparation and property of the HAP/6-TCP/AG composite scaffold had been investigated. The influences of sodium alginate on porosity, intensity, micro-structure and pore diameter of the scaffold were studied. The biocompatibility of the HAP/6-TCP/AG compound scaffold was verified by co-culturing with bone marrow-derived mesenchymal stem cells in vitro. The factors that affected the biocompatibility of the compound scaffold were analyzed.It was shown that sodium alginate was attached well with the HAP/fi-TCP scaffold. The intensity of the HAP /6-TCP scaffold was increased evidently when sodium alginate was added to the HAP /6-TCP scaffold. The porosity of the HAP /6-TCP/ AG scaffold was reduced and the intensity of the HAP /6-TCP/ AG scaffold was increased with the increase of sodium alginate. The proportion of the small pore was raised because Sodium alginate was network on the HAP /6-TCP scaffold. The HAP /6-TCP/ AG scaffold had better stem cells biocompatibility. Netty sodium alginate pore could provide abundant area for the adhesion of the stem cell. Sodium alginate brought hydrophilic carboxyl and hydroxyl for the scaffold and increased the hydrophilicity of the HAP /6-TCP scaffold. These factors made bone marrow-derived mesenchymal stem cells attach to the composite scaffold and grew well. The HAP/6-TCP/ AG scaffold adapted to the adhesion and the growth of stem cells when the content of sodium alginate was between 10% and 14%.From the investigation above, it was clear seen that chitin and sodium alginate can increase the intensity of the HAP /6-TCP scaffold and improve the stem cells biocompatibility of the HAP /6-TCP scaffold.