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

Abstract

A series of porous chitin matrices were fabricated by freezing and lyophilization of chitin gels cast from a 5% N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl) solvent system. The porous chitin matrices were found to have uniform pore structure in the micron range. Scanning electron microscopy (SEM) revealed that the pore size of the porous chitin matrices varied according to the freezing method prior to lyophilization. By subjecting the chitin gels to dry-ice/acetone (-38 °C), the final porous chitin matrix gave pore dimensions measuring 200-500 μm with 69% porosity. A smaller pore dimension of 100-200 μm with 61% porosity was produced when the chitin gels were frozen by liquid nitrogen (-196 °C) and 10 μm pores with 54% porosity were produced when the gels were placed in a freezer (-20 °C) for 20 min. In comparison, lower porosity structures of ca. 10% porosity were obtained from both air-dried and critical point dried chitin gels. Furthermore, a low gel concentration (<0.5%, w/w) also produced porous morphology by vacuum drying without any freezing and lyophilization. The resulting pore properties influenced the water uptake profile of the materials in water. These porous chitin matrices are found to be non-cytotoxic and to hold promise as potential structural scaffolds for cell growth and proliferation in vitro.