Alginate-chitosan/hydroxyapatite polyelectrolyte complex porous scaffolds: preparation and characterization.

Porous scaffolds composed of alginate (AG) and chitosan (CS) were fabricated by combining the formation of polyelectrolyte complex (PEC) with freeze-drying. The AG scaffold was used as a framework with uniformly distributed and interconnected pore structure. The chitosan or chitosan/hydroxyapatite (CS/HA) composite solution was introduced into the pores of AG scaffold to form PEC scaffolds. FT-IR, XRD and XPS analysis confirmed that CS or CS/HA was coated on the AG scaffold surface. Microstructure, porosity, mechanical strength and thermal stability of PEC scaffolds were also investigated. The AG-CS PEC scaffold and Ca2+ crosslinked AG scaffold showed smaller average pore diameter and lower porosity than those of uncrosslinked AG scaffold. Moreover, compared with Ca2+ crosslinked AG scaffold, AG-CS PEC scaffold exhibited higher mechanical strength and better thermal stability.