Elastic and macroporous agarose-gelatin cryogels with isotropic and anisotropic porosity for tissue engineering.

The focus of this work was to design a macroporous scaffold with controlled porosity in isotropic and anisotropic manner for tissue-engineering applications. Agarose-gelatin scaffolds were synthesized by cryogelation method, in which agarose was used to improve the mechanical characteristics and gelatin-provided amiable property of elasticity, cell adhesion, and cell proliferation in the scaffold. Agarose-gelatin (8%) cryogels synthesized in two different solvent systems (i.e., water and 0.1% acetic acid) at subzero temperature (-12 degrees C) showed well-interconnected porous structure. The agarose-gelatin cryogel synthesized in water solvent system (WSS) showed gradient porosity with an average pore diameter of a monolith (four sections from bottom to top; height 5 mm and diameter 13 mm each) ranging from 76 to 187 microm. The monolith of agarose-gelatin synthesized in 0.1% acetic acid solvent system (0.1% ASS) did not show any remarkable difference in average pore diameter of a monolith to their whole column length as revealed by scanning electron microscopy (SEM). These cryogels swelled up to approximately 90% of their capacity within 1 min. The aggregate tensile modulus showed good elasticity of the cryogels, in which agarose-gelatin synthesized in WSS showed higher tensile modulus, that is, 380.23 +/- 63.97 kPa in comparison with agarose-gelatin synthesized in 0.1% ASS, i.e., 278.08 +/- 94.08 kPa. The unconfined fatigue observation with varying strain (10-40%) and varying frequencies (2 and 5 Hz) showed no deformation of cryogels. The fibroblast (Cos-7) cell line seeded on the scaffold displayed good cell attachment in both types of cryogels and MTT assay showed good cell compatibility and favorable conditions for cell proliferation. These results indicate that agarose-gelatin cryogels can be a promising material of choice for tissue-engineering applications.