Preparation and evaluation of porous alginate/ hydroxyapatite composite scaffold coated with a biodegradable triblock copolymer

Abstract

Background: The scaffolds for bone tissue engineering must meet the functional requirements such as porosity, biocompatibility, and biodegradability. Composite materials could improve mechanical properties compared with polymers, and structural integrity and flexibility compared with brittle ceramics. Objective: The effect of a biodegradable triblock copolymer in the cell attachment into the alginate/hydroxyapatite composite scaffold was evaluated. Methods: Scaffolds were fabricated by freeze-drying method in different alginate/hydroxyapatite weight ratios. Hydroxyapatite was incorporated into the alginate gel solution to improve both the mechanical and cellattachment properties of the scaffolds. The scaffolds were then coated with triblock copolymer (as a surface modifier) and sterilized by ultraviolet light. Then, human mesenchymal stem cells were cultured on the scaffolds, which are an attractive cell source for tissue engineering. Results: Cell adhesion to the scaffolds was observed after three days by 4, 6-diamidino-2-phenylindole (DAPI) fluorescence microscopy. In addition, microstructural observation with SEM suggests the formation of about 50 micrometer size pores and interconnected porosity so that cell adhesion within this structure is well in depth as also observed in DAPI results. Conclusion: These results suggest that the triblock-coated alginate/hydroxyapatite porous scaffolds could provide enhanced cell adhesion and proliferation, which may be a promising approach for tissue-engineering applications. Keywords: Alginate, cell adhesion, freeze-drying, human mesenchymal stem cells, hydroxyapatite, porous scaffold, tissue engineering