Porous chitin matrices for tissue engineering: Fabrication and in vitro cytotoxic assessment

A series of porous chitin matrices were fabricated by freezing and lyophili zation of chitin gels cast from a 5% N,N-dimethylacetamide (DMAc)/lithium c hloride (LiCl) solvent system. The porous chitin matrices were found to hav e uniform pore structure in the micron range. Scanning electron microscopy (SEM) revealed that the pore size of the porous chitin matrices varied acco rding to the freezing method prior to lyophilization. By subjecting the chi tin gels to dry-ice/ acetone (-38 degreesC), the final porous chitin matrix pave pore dimensions measuring 300-500 mum with 69% porosity. A smaller po re dimension of 100-200 mum with 61% porosity was produced when the chitin gels were frozen by liquid nitrogen (-196 degreesC) and 10 mum pores with 5 4% porosity were produced when the gels were placed in a freezer (-20 degre esC) for 20 min. In comparison. lower porosity structures of ca. 10% porosi ty were obtained from both air-dried and critical point dried chitin gels. Furthermore. a low gel concentration (<0.5%, w/w) also produced porous morp hology by vacuum drying without any freezing and lyophilization. The result ing pore properties influenced the water uptake profile of the materials in water. These porous chitin matrices are found to be non-cytotoxic and to h old promise as potential structural scaffolds for cell growth and prolifera tion in vitro.