Abstract: A novel method is proposed to fabricate scaffolds with three-grade pores, high porosity and interconnected macro-pores. It is based on rapid prototyping (RP), phase separation and particulate leaching. The particulate is mixed into polymer solution homogeneously. And then the slurry is extruded into a low-temperature room as designed in the computer by a volume-actuated injecting (VAI) nozzle. Then a frozen scaffold with macro-pores more than 100 μm in diameter is obtained. Micro-pores less than 10 μm and between 10 μm and 100 μm in diameter also can be obtained by the respective removal of solvent and particulate. The porosity is higher than 90%. The concentration of polymer and particulate can influence both the porosity and viscosity of the slurry. Therefore, polymer with different molecular weight can be processed by the VAI nozzle to get a high-porosity scaffold. Several poly(Lactide-co-glycolide) (PLGA) scaffolds with low molecular weight and high porosity are fabricated for cartilage tissue engineering.

Key words: Particulate leaching, Phase separation, Porosity, Rapid prototyping, Scaffold, Tissue engineering, 3D model, collision, moving track, railway vehicle