Abstract: Porous composite scaffolds of nano-hydroxyapatite/chitosan/carboxymethyl cellulose (n-HA/CS-CMC) with different weight ratios (0/50/50, 20/40/40, 40/30/30 and 70/15/15, respectively) were prepared by freeze-drying method for bone tissue engineering scaffold. The mechanism of formation of the composite scaffolds and the effects of inorganic component (n-HA) on the porous morphologies, mechanical properties and their degradation rate of n-HA/CS-CMC composite scaffolds were investigated by means of IR, XRD, SEM, TEM, universal material test machine and PBS soaking. The results show that the composite scaffolds is mainly formed through the complexation reaction between the two opposite polyions of CS and CMC, then n-HA is firmly incorporated into the polyelectrolyte matrix of CS-CMC without agglomeration. The addition of inorganic component n-HA into the system of CS-CMC, which decreases slightly the regularity of pores and porosities of the n-HA/CS-CMC composite scaffolds. However, the addition of inorganic component n-HA increases the compressive strength and steps down the in ~vitro degradation of the composite scaffolds. The composite scaffold with weight ratio of inorganic component (n-HA) of 40% is most suitable for bone tissue engineering scaffold in view of its highly interconnected porous structure, high compressive strength and the acceptable degradation rate.

Key words: nano-hydroxyapatite, chitosan, carboxymethyl cellulose, scaffold