Role of poly(lactide-co-glycolide) particle size on gas-foamed scaffolds

Macroporous polymeric scaffolds are frequently used in tissue engineering to allow for cell seeding and host cell invasion of the scaffold following implantation. The process of gas foaming/particulate leaching (GF/PL) is one method to form porous three dimensional scaffolds from particulate poly(lactide-co-glycolide) (PLG). The current study was designed to test the hypothesis that the size of the polymer particles used in this process will control the properties of the scaffolds. Scaffolds were prepared from PLG particles of various sizes (less than 75 microm, 75-106 microm, 106-250 microm and 250-425 microm) and subsequently analyzed. Scaffolds formed from large particles (250-425 microm) displayed significantly decreased compressive moduli, as compared to scaffolds fabricated from smaller particles. In addition, these scaffolds have a pore structure that is less interconnected and contains closed pores. Analysis of tissue in-growth, utilizing a novel computer-aided method, demonstrated that scaffolds formed from smaller particle sizes (less than 106 microm) have significantly more tissue penetration than those formed from larger particle sizes (greater than 106 microm). These results indicate that using small PLG particles (less than 106 microm) leads to high elastic moduli, provides a more interconnected pore structure and promotes greater tissue penetration into the scaffolds in vivo.