Porous chitosan scaffolds for tissue engineering.

The wide array of tissue engineering applications exacerbates the need for biodegradable materials with broad potential. Chitosan, the partially deacetylated derivative of chitin, may be one such material. In this study, we examined the use of chitosan for formation of porous scaffolds of controlled microstructure in several tissue-relevant geometries. Porous chitosan materials were prepared by controlled freezing and lyophilization of chitosan solutions and gels. The materials were characterized via light and scanning electron microscopy as well as tensile testing. The scaffolds formed included porous membranes, blocks, tubes and beads. Mean pore diameters could be controlled within the range 1-250 microm, by varying the freezing conditions. Freshly lyophilized chitosan scaffolds could be treated with glycosaminoglycans to form ionic complex materials which retained the original pore structure. Chitosan scaffolds could be rehydrated via an ethanol series to avoid the stiffening caused by rehydration in basic solutions. Hydrated porous chitosan membranes were at least twice as extensible as non-porous chitosan membranes, but their elastic moduli and tensile strengths were about tenfold lower than non-porous controls. The methods and structures described here provide a starting point for the design and fabrication of a family of polysaccharide based scaffold materials with potentially broad applicability.