Bio-hybrid scaffolds for bone tissue engineering: nano-hydroxyapatite/chitosan composites

摘要

Natural bone ECM is a hierarchical nano-composite made of an inorganic phase deposited within an organic matrix. In order to mimic the bone highly organized hybrid structure and functionality, strategies that allow assembling ceramic and polymer phase can be applied. To this aim, we investigated an in situ growth method able to nucleate a nano-Hydroxyapatite (nHAp) phase into and around the interconnected porous structure of chitosan sponges. By increasing the calcium and phosphate concentration in the meta-stable solution used for the nHAp nucleation, the inorganic phase raised proportionally, in the range 10%-30% wt. In order to be compared with nHAp loaded scaffolds, pure chitosan samples have been produced by cross-linking biopolymer with arginine. Moreover, nHAp loaded samples, containing the 20 % wt of inorganic phase have been prepared by simply mixing low crystalline nHAp powders with the chitosan gel. The in situ nucleation method highlighted evident advantages in terms of nano-phase distribution and mechanical performances with respect to a merely mixing procedure.