Design and manufacture of microporous polymeric materials with hierarchal complex structure for biomedical application

Porous biodegradable polymeric scaffolds are essential for tissue engineering application since they should provide the adequate three-dimensional structure for cellular attachment and tissue development. In particular, pore size and shape and overall porosity are key structural features in controlling neotissue formation. Since scaffolds structural properties play a relevant role in all processes involved in tissue genesis including cell adhesion, migration, proliferation, growth, differentiation and biosynthesis, an accurate control over the pore size and its distribution, pore shape, pore interconnectivity, and overall porosity of scaffolds is mandatory for the success of any tissue engineering approach. Several methods have been proposed to tailor make porous scaffolds to obtain the desired pore structure. Here, three techniques to emboss a controlled pattern of porosity in biodegradable polymers, particulate leaching, phase separation and gas foaming along with their combinations, are critically reviewed highlighting process-structure-property relationship.