A method for solvent-free fabrication of porous polymer using solid-state foaming and ultrasound for tissue engineering applications

Most of the existing fabrication techniques for tissue engineering scaffolds require the use of organic solvents that may never be fully removed even after long leaching hours. The residues of these organic solvents reduce the ability of biological cells to form new tissue. This paper presents an approach toward solvent-free fabrication of tissue engineering scaffolds. Interconnected porous structures were created using solid-state foaming and ultrasound. The material used in this study was polylactic acid (PLA) and the blowing agent was CO2. In order to determine suitable process conditions, saturation and foaming studies were first conducted. Selected foam samples were then processed using pulsed ultrasound. The microstructures before and after the ultrasound processing were compared. It was shown that the inter-pore connectivity of the solid-state foams was substantially enhanced. The combined solid-state foaming and ultrasound processing provide a way to fabricate porous polymer for potential tissue engineering applications.