Macroporous 3D printed structures for regenerative medicine applications

The use of natural biopolymers as a core material to produce cell-laden scaffolds has been recognized and extensively utilized for tissue engineering purposes due to their advantageous biocompatibility and tunable biodegradation rate. The morphology and average pore size play, however, a major role in biological processes affecting cell proliferation kinetics as well as tissue regeneration processes associated with extracellular matrix formation. Shear thinning properties of the inks employed in 3D printing for high-accuracy hydrogel scaffold fabrication are often associated with compromises in morphology, such as reduced pore sizes. Here, we report on a carefully optimized composite formulation of (1:1) gelatin/oxidized alginate (Gel/OxAlg) that allows combining 3D printing and cryogelation techniques for simple and low-cost fabrication of biocompatible hydrogel scaffolds, characterized by high porosity and extra-large pore size (d > 100 μm). Based on the morphological characteristics and obtained cell viability data, the fabricated scaffolds might be used as a platform for a variety of tissue engineering applications.