Supercritical CO2 processing of polymers for the production of materials with applications in tissue engineering and drug delivery

Supercritical carbon dioxide (SCCO2) was used for the preparation of foamed sponges and intermingled fibers of biopolymers with potential applications in tissue engineering and drug delivery. The work was focused on the processing of both biodegradable polylactic acid (l-PLA) and non-biodegradable polymethylmethacrylate (PMMA) homopolymers. Monolithic porous sponges of amorphous PMMA were prepared using SCCO2 as a porogen agent by simple swelling and foaming. Under similar experimental conditions, l-PLA was crystallized. The study also addresses the impregnation of biopolymers with an active agent dispersed in SCCO2. The drug used for impregnation was triflusal, a platelet antiaggregant inhibitor for thrombogenic cardiovascular diseases. Foaming often leads to a closed pore structure after depressurization which is disadvantageous for 3D scaffolds as it does not fulfill the requirement of interconnectivity necessary for cell migration. To overcome these drawbacks, fibers forming macroporous structures were prepared using a semicontinuous antisolvent (SAS) technique.